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T01 Ac. meas. & instrum. [clear filter]
Monday, July 8
 

11:00 EDT

AN ANALYTICAL MODEL OF BURIED PLASTIC GAS PIPE FOR ACOUSTIC DETECTION
Buried piping systems play a very important role in modern societies, especially in transporting fluids and gases for everyday use. Within these systems, plastic pipes have been widely used in recent decades because of their relatively low failure rates compared against other type of pipes in service. Unfortunately, the records of these underground utilities are often inaccurate and incomplete. Problems associated with inaccurate location of buried pipes are exacerbated in the presence of rapid development of urbanization, which increases both the difficulty and economic costs of excavation work. In response to this, trenchless technologies have been developed and shown effective in locating buried piping systems. In particular, acoustic detection method is considerably promising in locating plastic pipes. By applying acoustic excitation on one part of the pipe and analyzing the ground surface vibration, the location of the buried pipe can be determined. Whilst there are existing studies relating to plastic water pipes in this field, limited research has been carried out on buried gas pipes detection. Based on the model of buried fluid-filled pipe, an analytical model of buried plastic gas pipe will be studied in this paper. The analytical solution and numerical simulation results of the mode waves will be presented and their characteristics will be analyzed. Moreover, in our proposed model, the ground surface vibration directly above the pipe will be expressed as the result of radiated conical waves resulted from the propagation of the specific mode wave inside the pipe. Hence, there is no need to approximate conical waves as plane waves, which will make our analytical solution more accurate. This work can provide theoretical insight to acoustic detection techniques used for locating buried pipes.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
LY
HD
CD
WX
CH

Chen Hao

RESEARCH ON TRANSIENT TORSIONAL VIBRATION OF PROPULSION SHAFT WITH PARALLELING ENGINE UNDER TORQUE IMPACT, School of Energy and Power Engineering, Wuhan University of Technology, Wuhan, China

Monday July 8, 2019 11:00 - 11:20 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS01 Ac imag & ac detection

11:20 EDT

INVERSE ANALYSIS OF VOCAL SOUND SOURCE BY ACOUSTIC ANALYSIS OF THE VOCAL TRACT
Diseases occurring near the vocal cords, such as laryngeal cancer, often cause voice disturbance as an initial symptom. As an acoustic diagnostic method for such diseases, the GRBAS (grade, roughness, breathiness, asthenia, strain) scale is widely used, but its objectivity is not well estab-lished. Instead, more accurate diagnosis may be possible by capturing the waveform of the volume velocity at the vocal cords (the vocal sound-source waveform). The aim of this study is to enable diagnosis of diseases near the vocal cords by identifying the sound-source waveform from voice measurements. In the proposed method, an analytical model of the vocal tract is used to identify the sound source. The air inside the vocal tract is modeled as concentrated masses connected by linear springs and dampers. The vocal tract shape is identified by making the natural frequencies of the analytical model correspond to the measured formant frequencies. The sound-source wave-form is calculated from the analytical model by applying the measured voice (sound pressure) to the lip position of the identified vocal tract. To assess the validity of the proposed method, an ex-perimental device was made to simulate the human voice mechanism. The device is equipped with artificial vocal cords made of a urethane elastomer that are self-excited by air flow. The sound pressure equivalent to the voice was measured using a microphone set at the lip position of the experimental device, and the flow velocity at the artificial vocal cords was measured using a laser Doppler velocimeter (LDV). To assess the model's validity, the sound-source waveform iden-tified from the measured sound pressure was compared with the waveform measured using the LDV.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
YK
IS
KY
KS

Monday July 8, 2019 11:20 - 11:40 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS01 Ac imag & ac detection

11:40 EDT

EXPERIMENTAL MODAL ANALYSIS BASED ON NON-CONTACT MEASUREMENTS WITH A COMMERCIAL MICROPHONE ARRAY
Experimental modal analysis is a tool for measuring the dynamic properties of structures under vibration excitation. In order to improve the understanding of the structural dynamic behavior of complex structures, modal parameters, such as eigenfrequencies, damping ratios, and mode shapes are of high importance. Furthermore, based on the mode shapes, the structural integrity of a component can be assessed and monitored. EMA results are also used in research and development for the validation and optimization of numerical models. The advantage of a non-contact measurement of the vibration patterns is that there is no damage or contamination of the material surface. In addition, the modal quantities are not contaminated by the additional weight of vibration transducers, so that the dynamic response of the system is not influenced by the measurement itself. In contrast to other non-contact methods (e.g. laser vibrometers), the use of a suitable microphone array allows the simultaneous detection of the entire surface vibration covered by the array. Time-consuming, selective measurements of individual measuring points and the merging to point clouds are therefore no longer necessary. The modal analysis method is demonstrated in experiments on application-oriented, large-area structures. The parameter of interest, the mode shapes, are determined by measuring the pressure fluctuations in the near field of the structure. A commercial 120-channel microphone array with an integrated optical camera (Fibonacci120 AC Pro, gfai tech GmbH) is used for this purpose. The integrated optical camera allows to assign the measured system response to the corresponding surface section. The entire surface of the examined structures is covered by the planar microphone array, which has a diameter of 0.5 m. Measurements with a laser vibrometer are used to validate the data obtained from the microphone measurements. The modal assurance criterion (MAC) is used to compare the mode shapes determined by both methods.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
BO
GJ
HJ

Monday July 8, 2019 11:40 - 12:00 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS01 Ac imag & ac detection

12:20 EDT

NUMERICAL SIMULATION OF BUBBLE SIZE MEASUREMENT VIA WAVE PHASE CONJUGATION
Measuring characteristics of gas bubbles in a fluid is among important and challenging tasks in many industrial settings. Such measurements can be carried out more efficiently and accurately by using a Wave Phase Conjugation (WPC) device due to its useful relevant properties such as signal retro-focusing and compensation for phase distortions. In the present work, this technique is explored via numerical modelling in application to bubble size measurements. A modified version of the high-order Nodal Discontinuous Galerkin (NDG) method, which is based on the non-collocated solution and flux bases, is implemented for modelling of the acoustic wave propagation in the WPC conjugator and the surrounding fluid. Additional volume-averaged terms are added to the model to account for the presence of bubbles in the fluid. The modified Keller-Miksis model is employed to simulate vibrations of bubbles exposed to acoustic waves. After the verification and validation of the numerical model, the interaction of bubble dynamics with the WPC process is examined. The results demonstrate that the WPC-based technique is an adequate tool to be used for measuring bubble dimensions via stimulation of the bubble natural frequency.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
PP
MA
TE
MA

Monday July 8, 2019 12:20 - 12:40 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS01 Ac imag & ac detection

15:30 EDT

VIBRATION ANALYSIS OF ELECTRICAL CONNECTOR UNDER DIFFERENT AMBIENT CONDITIONS
In automotive field, vehicle vibrations induce movement on hundreds of connectors which are located near the engine or inside the vehicle compartment. These vibrations produce induced-frictions between male and female parts in contact inside the connector (named pin and clip respectively) and generate electrical failure due to the well-known fretting-corrosion phenomenon. A relative displacement of 5 micrometers between the pin and the clip is sufficient to generate debris at the contact zone and lead to an intermittent conduction at this interface which represents 60 % of electrical failure within a car. Connectors are made of a substrate of copper alloy plated with a tin layer. Tin is used to coat and protect the copper substrate. The oxygen reacts with the soft tin and formed a hard and brittle layer of tin debris and cause high degradations. This third-body layer is composed of insulated (oxide) and conductive debris (non-oxides). The electrical conduction could be disturbed through this granular layer. The displacement and evacuation of oxidized debris is not so well understand. For our study, an automotive connector was submitted to vibration tests. The used bench is composed of a piezo-electric actuator which provides a controlled movement between the clip and the pin. A generator provides a stable current through the connector and the measurement were performed with a voltmeter, a temperature controller and an oscilloscope for real-time analysis. The bench is mounted on an anti-vibration table in order to avoid external vibrations. The measurement of electrical behavior was undertaken under two atmospheres: air and nitrogen gas. The use of air atmosphere shows a typical augmentation of the amplitude of the contact voltage whereas the use of nitrogen gas induces a contact voltage decrease. The measurement of these electrical characteristics provides new information to understand the fretting-corrosion phenomena.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
EA
LJ
LS

Monday July 8, 2019 15:30 - 15:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

15:50 EDT

EXPERIMENTAL RESULTS OF DOUBLE NEAR-FIELD HOLOGRAPHY METHOD WITH VARIABLE DISTANCE BETWEEN MEASUREMENT PLANES
I am now developing the new sound localization method, the Double Near-field Acoustic Holography (DNAH) method. This method can localize the location of low frequency sound source precisely. In this method, the measurement plane of NAH method is doubled. To measure the sound information on the doubled measurement plane, two microphones which move vertically and horizontally are used. In former research, the distance between two microphones, the distance between two measurement planes is 0.2m. In this paper, the experiments are carried out with variable distance. As the result, it is verified that the DNAH method is also effective in the case that the distance between two microphones is short, several cm. Therefore, it is proved that the intensity probes can be used for measurement of DNAH method.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
NM

Monday July 8, 2019 15:50 - 16:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

16:10 EDT

HYBRID PIEZOELECTRIC VEHICLES (HPEV™) AND MOTORS (HPEM™)
The paper describes a new class of a hybrid vehicle that uses piezoelectric devices for powering an electric motor while still using conventional fuels, such as gas, diesel, or oil. The installed piezoelectric devices can transform the mechanical energy of the moving pistons or crankshafts into electrical energy, which can be stored in the capacitor or the battery charger. Consequently, the stored electrical energy powers an electric motor, which can supplement the conventional gasoline or diesel engine or work independently. The solution to the problem can significantly reduce the consumption of the conventional fuel, diversify transportation fuel supply, and reduce the air pollution. Use of piezoelectric devices for powering a supplemental electric motor will lead to the development of a new generation of hybrid vehicles, where the mechanical energy of the existing conventional gasoline engine will be converted to electrical energy without significant changes in the design of the existing automobile engine and generator. Using piezoelectric elements for powering the motor can significantly increase the cost-effectiveness of the hybrid vehicles and simplify the currently used charging system of the electric vehicles. The principle of operation is based on the unique properties of piezoelectric materials, which are able to generate an electrical voltage when they are mechanically stressed. The preliminary experimental results demonstrate that a single piezoelectric element under transient dynamic mechanical load can generate a pulse of an electrical voltage in the range of tens or even hundreds of kilovolts. Keywords: power harvesting, piezoelectricity, hybrid vehicles
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
GV
KN

Monday July 8, 2019 16:10 - 16:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

16:30 EDT

IN-SITU MEASUREMENT OF ACOUSTIC IMPEDANCE AT OBLIQUE INCIDENCE BY USING A PARAMETRIC LOUDSPEAKER
Acoustic measurements of an architectural material in a free field or in-situ are influenced by diffraction from sample edges and reflections from other room boundaries. These undesired waves may cause a measurement error. Especially, a measurement at oblique incidence is quite difficult as the incident angle is larger or the sample size is smaller. In this study, a parametric loudspeaker, which is super-directive by utilizing the nonlinearity of ultrasound, is used to overcome the difficulty. The parametric loudspeaker can reduce the undesired waves by focusing the incident sound onto a small spatial range and will be used as a simple and accurate measurement method. However, the super strong ultrasound used as the source signal causes the nonlinear distortion called "pseudo sound" on the microphone surface and increases the measurement errors. In order to minimize such induced errors, two methods are investigated experimentally: acoustic filtering via phononic crystals and the phase-cancellation excitation of the ultrasound. In our previous work, acoustic impedance of a glass-wool board at oblique incidence is measured using these two methods in an anechoic chamber. The results show that the proposed method is effective at frequencies above 800 Hz in a free field. Based on this, in the presented study, in-situ measurements are conducted in a conference room. This investigation shows that the proposed method can efficiently estimate the acoustic impedance at oblique incidence in-situ at frequencies above 800 Hz.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
SA
LH
SS
TS

Monday July 8, 2019 16:30 - 16:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

16:50 EDT

DIFFERENTIAL MICROPHONE ARRAY: DESIGN FOR ACOUSTIC LOCALIZATION WITHIN AIRCRAFT CABIN
Acoustic localization inside aircraft cabins is of increasing interest. It allows to identify issues through sound measurements in a tight schedule, especially in an industrial context. Moreover, in such environments, the reverberant nature of the acoustic field and the space constraints make it difficult to use conventional localization method. For instance, beamforming among other localization techniques, requires large microphone arrays for applications to low- and mid-frequency range. This study combines the development of an array geometry and the definition of a post-processing method adapted to applications within aircraft. The research originality lies in the considered post-processing method, consisting in a subtractive array based on high-order differential microphones and exploiting acoustic gradient properties. With such a method, the use of a compact microphone array with a strong directivity in low frequencies is proposed. Precisely, a fourth-order analytical model is established, driven by the desired directivity and the sensitivity to noise, especially at low frequencies. The study aims at developing a compact array, allowing mainly localization from 500Hz up to 1000Hz, taking into account the space limitations. The frequency band target is used to drive the simulations and the antenna geometry definition. An experimental proof of concept is tested in an anechoic room. Simulations and experimental results are compared to an analytical modeling. Good agreement between them is observed. The comparison highlights the method advantages as well as the experimental limitations of the designed linear array. Then, a first localization test is performed using the experimental database. Finally, a modification of the post-processing method is suggested, with an improvement of the achieved directivity in the targeted low-frequency band.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
IM
MB
DJ
BO
JD

Monday July 8, 2019 16:50 - 17:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

17:30 EDT

ACOUSTIC DECISION SUPPORT SMARTPHONE APPLICATION FOR BUILDING STAKEHOLDERS
Acoustic comfort is a very important feature when designing a room used by many people such as a gymnasium, a concert hall, a conference room or an office. It is mainly related to reverberation time and other characteristics of the room. Building and construction stakeholders (architects, contractor, designers, developers, etc.) usually work with acoustic consultants to optimize room acoustics. However, they do not have a simple decision support tool, which provides both guidance and recommendations to make preliminary decisions regarding acoustics, therefore saving time and money. A smartphone application (ClapReverb) was designed to measure and compute reverberation time in the medium range frequency domain. The user needs to produce a few handclaps while following instructions on the screen. This method does not require additional hardware because the sound is recorded using the inboard microphone of the smartphone. The upcoming results provide the room's reverberation time and recommendations on acoustic comfort. Thus, two main concerns were addressed in this study: 1) defining the range of validity of the measurement through handclaps and the smartphone microphone, 2) developing an ergonomic application useful for building and construction stakeholders. A parametric study has been conducted to develop a robust process to measure reverberation time and to define the range of validity of the measurement in terms of frequency, reverberation time error, room volume, ambient noise, handclap type, etc. Measurements were compared to a reference method, which was wooden clapping device impulses recorded with a class-1 microphone and analyzed with a Scilab analysis program that complied with ISO-3382 Standard. Overall reverberation time results showed a mean absolute error of 0.09 s computed by ClapReverb (mean relative error of 6.0 %). ClapReverb provides reliable results with ambient noise up to 60 dBA, and is therefore a promising easy-to-use smartphone application which democratizes acoustics and helps stakeholders to optimize room acoustics.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
MA
DR
BJ

Monday July 8, 2019 17:30 - 17:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

17:50 EDT

SOUND FIELD RECONSTRUCTION IN A ROOM USING LOW-RANK APPROXIMATION OF MODESHAPES: VALIDATION AND APPLICATION
Sound field reconstruction in rooms is a subject of high interest in the domain of acoustic research. At low frequencies, a thorough understanding of sound field distribution is the key to identifying imbalance and irregularities caused by the room which will eventually lead to the coloration of sounds. Traditionally, an accurate rendering of the sound field would require an impractically high number of microphone measurements at multiple locations in the room. Our research tackles this issue by exploiting the sparsity in modal decomposition expression of the sound field with the use of low-rank approximation technique to significantly reduce the number of measurements. We first benchmark the techniques on an existing non-rectangular room model in Finite Element Method simulation with different room settings to validate the high robustness and accuracy of the framework. The evaluation gives accurate results as the reconstructed sound fields are in very good agreement with the simulation reference and the existence of mode shapes are accurately depicted. Finally, we also prove that the framework performs well in cases where the sound field is altered by placing several active low frequency absorbers inside the room. This shows that our framework can be further extended to assess the performance of passive/active absorbers in the domain of room modes equalization.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
LH
PV

Monday July 8, 2019 17:50 - 18:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

18:10 EDT

A NEW TACTILE SENSOR FOR WIDE RANGE FORCE UTILIZING MAGNETORHEOLOGICAL FLUID IMMERSED SPONGES
In this research, three different magnetorheological (MR) fluids are used to fabricate a tactile sensor which can be applicable to robot-assisted minimally invasive surgery (RMIS). As a first step, MR sponge cell is prepared by flowing the fluids into the pores of the sponge. Secondly, the MR sponge cell is wrapped to avoid the leakage and also provide the softness. Then, the field-dependent compressive force of MR sponge cell is experimentally measured using a tension and compression tester. Finally, in order to validate the generation of the desired tactile force from the proposed MR sponge cell, the force tracking control is performed within the force range required for the RMIS operation.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
CS
PY
YJ

Monday July 8, 2019 18:10 - 18:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

18:30 EDT

STUDY ON SKIN PROPAGATION OF SPEECH USING THREE DIMENSIONAL DISPLACEMENT MEASUREMENT
Many researchers focus on speech and body-conducted speech including body-conducted speech to clear propagation mechanisms for making innovative interfaces. Especially, skin propagation of speech on a face skin analyzed by a Laser Doppler Vibrometer generally. In this study, it is presented that sound measurement on skin propagation during vocaliza-tion using three dimensional displacement measurement. At this experiment, each subject vocalized 7 vocabularies that are 5 Japanese vowels, 1 syllabic nasal and 1 silence. Then, speech, body-conducted speech and skin displacements is measured for analysis with Spectrum and its envelope. Speech is recorded at about 20 cm from a mouth with a micro-phone, and body-conducted speech is recorded at upper left of upper lip with an accel-erometer. The displacements are captured from upper lip using the 3D displacement measurement. As the results, direction and its attenuation depend on each axis and a trans-fer function can be obtained that converts between the dimensions of acceleration and dis-placement at the same measurement location on the lip.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
IS
NM
IS
FY

Monday July 8, 2019 18:30 - 18:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens
 
Tuesday, July 9
 

10:30 EDT

CHARACTERIZATION OF SOIL ATTENUATION FOR ACOUSTIC CONDITION ASSESSMENT OF WATER-FILLED METAL PIPES
Acoustic-based technologies provide economic and non-disruptive means of actively monitoring water networks, accurately detecting leaks, and efficiently assessing the condition of buried pipelines. They rely on interpreting the propagation of sound waves in a buried pipeline, which is a function of the properties of the fluid, conveying pipe, and surrounding medium. Currently, there are no non-invasive methods of measuring tuberculation of iron pipes. Tuberculation is an accumulation of corrosion products on the inside of water mains which can result in reduced pressure in water distribution systems and increases in the potential for leaks. This research addresses the attenuation of sound waves in metallic pipes in an attempt to predict the degree of tuberculation. At present, we are unable to distinguish between the attenuation associated with the inside surface of the pipe (tuberculation) and the attenuation caused by the surrounding medium (usually soil). This project involved both modeling and experimental phases. First, influencing parameters from the soil were identified and incorporated into a wave attenuation model. Then, this model was tested and validated in a realistic setting. Field tests were conducted on a 100 m long pressurized iron pipe in order to compare and analyze the attenuation characteristics of exposed and buried pipes. The results from attenuation measurements for different configurations showed good agreement with the attenuation predictions from the model of soil-pipe interactions (less than 3% difference). With this better understanding of how the soil affects acoustic wave propagation, the attenuation associated with the inside surface of the pipe can be isolated and used to estimate the degree of tuberculation. Such an interpretation technique will allow water utilities to better understand their water networks, empowering them to better manage our precious water resources and infrastructure.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
PS
MM
RB
BV
MI

Tuesday July 9, 2019 10:30 - 10:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

10:30 EDT

EFFECT OF BOUNDARY CONDITIONS ON RECEIVING TRANSDUCER FOR LWD MULTIPOLE ACOUSTIC LOGGING TOOL
The receiving transducer is a key element of the LWD multipole acoustic logging tool, and its performance directly affects the signal quality. The effects of boundary conditions, metal substrate thickness and sealing way on the vibration mode and receiving sensitivity are analyzed by finite element method. The simulation results show that the clamped boundary condition at both ends is the most suitable mechanical installation way, because receiving sensitivity is the most gentle, undulation is the smallest, receiving sensitivity is relatively high in this condition. The thickness of intermediate metal substrate has a certain influence on the receiving sensitivity. The receiving sensitivity slightly rises with the increase of the metal substrate thickness, and the sensitivity jump point near the frequency of 3 kHz moves to the high frequency. If the receiving transducer is sealed with cuboid shell in silicone oil, the sensitivity curve jumps at multiple frequency points, and the fluctuation becomes large in the working frequency. The numerical simulation results have a good guiding effect on the design, fabrication and correct installation of the transducers.
Authors
SZ
TX
SY
LX
CH

Tuesday July 9, 2019 10:30 - 13:00 EDT
St-Laurent 3, Board 05-A
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

10:30 EDT

RESEARCH ON FALSE SOURCE ELIMINATION METHOD IN MULTI-SOURCE LOCALIZATION BASED ON TDOA
This paper addresses source localization technique based on TDOA for the scenarios of multiple acoustic sources distributing in three-dimensional space. The triangulation method associated with the cross-correlation is used to locate the multiple sources. For multiple sources localization, false sources will be generated due to the error order of the estimated time difference of arrival. In order to eliminate the false sources, the array microphones are divided into two groups. The first group is used to locate the multiple sound sources. The second group is used to determine the true sound sources through the relative positional relationship between array microphones and sources. And the initial position of the true sources can be obtained. Then, the correct order of the estimated time difference of arrival for all the microphones can be acquired by the initial position of the true sources. Substituting the correctly matched values of the estimated time difference of arrival into the source location model, the final sources' locations can be figured out. The method proposed in this paper successfully eliminate the false sources in multiple sources localization based on TDOA, and what is more, the array microphones can be fully utilized to improve the positioning accuracy of multiple sound sources.
Authors
LH

Tuesday July 9, 2019 10:30 - 13:00 EDT
St-Laurent 3, Board 05-B
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

10:30 EDT

RESEARCH ON THE CONDITION CLUSTERING FOR UNDERWATER RADIATION NOISE EVALUATION OF DOUBLE-RIBBED CYLINDRICAL SHELL
To reduce the error while evaluating the radiation noise of ship with operational transfer path analysis method, an optimized method of ships' vibration transfer path analysis that based on condition clustering is proposed. Firstly, it constructs a complete acoustical clustering feature space with wavelet packet energy coefficient ratio, which can express good local property of noise in both time and frequency domains. This paper identifies and classifies the working condition through clustering analysis, establishes the transfer function database, thus evaluat-ing radiation noise by selecting the matched transfer feature function after matching working condition. Experiments with scaled cabin model show that the evaluation error of 1/3 octave radiation noise is less than 3dB, and verify the feasibility of operational transfer path analysis based on condition clustering.
Authors
RL
RX

Tuesday July 9, 2019 10:30 - 13:00 EDT
St-Laurent 3, Board 07-A
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

10:50 EDT

MESH CONDITION MONITORING FOR SPUR GEARS BY VIBRO-ACOUSTIC ADMITTANCE MODULATION OF PIEZOELECTRIC ELEMENTS ATTACHED ON THE END FACE
In this paper, a novel mesh condition monitoring method for spur gears is presented which utilizes a nonlinear vibro-acoustic effect on a piezoelectric element integrated on the end face of the drive gear. In the presented technique, the piezoelectric element is driven by a sinusoidal voltage source with an ultrasonic frequency to excite a certain vibration mode of the drive gear. The meshing motion of the gears yields a time-varying boundary condition at the contacting point between the drive and driven gears, which leads to a fluctuation of the scattering conditions for the ultrasonic elastic wave radiated from the piezoelectric layer. This nonlinear effect of vibro-acoustic interaction appears as a modulation of the coupled electromechanical admittance of the piezoelectric element, which can be observed as an amplitude and phase modulation of the current response of the piezoelectric element. In this preliminary study, a test rig consisting of a motor-driven pair of meshing spur gears with an electromagnetic powder brake for loading is developed, and the current responses of the piezoelectric element are investigated with low speed rotation under various loading levels.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
MA
NS
MT

Tuesday July 9, 2019 10:50 - 11:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

11:10 EDT

IN-SITU CHARACTERIZATION OF A VIBRO-ACOUSTIC SUBDOMAIN
For vibro-acoustic systems, such complex as a vehicle, modelling and understanding of acoustic transmission path are not straightforward tasks. Substructuring approaches can be very helpful for NVH engineers in different ways. The most interesting capabilities of substructuring approaches are (i) solving smaller sub-problems and (ii) mixing different modelling "solvers" (closed form solutions, numerical simulations or experiments). Therefore, using substructuring approach allows reaching higher frequencies or solving bigger systems and allows combining numerical and experimental descriptions of sub-problems. The latter point is particularly interesting when dealing with subdomains that remain difficult to model with numerical tools (assembly, trim, sandwich panels, porous materials, etc.). Impedance or mobility are at the basis of several substructuring methods like the Patch Transfer Functions (PTF) method. For this kind of methods, the (acoustic) impedance on the coupling surface characterizes the subdomain. This impedance is intrinsic of the subdomain and does not depend on the coupling to any other subdomain. The impedances are computed on "uncoupled" subdomains. This becomes problematic when one wants to obtain these impedances from measurements (a vehicle cabin cannot be uncoupled from the structure of the car for instance). The present works deals with a method developed to characterize the acoustic impedance of a passive subdomain directly using responses of the whole system (with coupled subdomains) and using an inverse approach. The theoretical background is presented and an original way to face ill-poseness of the problem is proposed. Finally, the method is validated on an experimental test case.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
TN
GM
BA
GJ

Tuesday July 9, 2019 11:10 - 11:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

11:30 EDT

Review of optical methods and the transition from a classical to quantum framework in acoustics
Metrology as a scientific field focuses specifically on the definition and realisation of the units of measurements specified within a particular reference framework but also their required traceabil-ity. Such traceability used to be derived through physical objects called artifacts but significant re-search has resulted in a traceability shift from artifacts (with the kilogram becoming the final unit) to fundamental quantities and nature constants derived mostly in a quantum manner and natural constants. This paper reviews the research work in the area of acoustical metrology and its associated branches and how such a transition between classical to quantum frameworks can take place.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
HL
YP
CW
KT

Tuesday July 9, 2019 11:30 - 11:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

11:50 EDT

SIGNAL PROCESSING AND ENVIRONMENTAL CONSIDERATIONS IN THE DEFINITION OF THE ACOUSTIC PASCAL USING OPTICS
The unit of sound pressure, the acoustic pascal is not defined in any standard in the area of sound-in-air metrology. Instead, the required parameter is the device sensitivity which is ex-pressed in decibels and is traceable though standards that rely on the existence of physical acoustical artifacts. However, the acoustic pascal has been experimentally realised using optics and is shown to be traceable through the metre, second and the kilogram. The definition of the kilogram in 2019 through fundamental constants, will allow all three aforementioned units to be traceable through quantum approaches and photon correlation will allow the definition of the acoustic pas-cal traceable through these three units in a direct and absolute manner without the reliance on physical artifacts.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
CW
KT

Tuesday July 9, 2019 11:50 - 12:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

12:10 EDT

CANCELLED: DESIGN OF THE WIRE SENSOR FOR MONITORING WATER PRESSURE IN PLASTIC PIPES
Pipelines as a major means of transporting water and gases, are susceptible to burst and leakage. Previous work on the pressure measurements in pipe networks has shown that water leakage is sensitive to pressure changes. To this end, acoustic/vibration sensors have been adopted for the detection and location of the suspected leaks in piping systems. In this paper wire sensors are designed to monitor water pressure due to leakage from plastic pipes. Sensitivity measurements are conducted in the laboratory in comparison with those using the conventional hydrophones to evaluate the performance of the wire sensor for pipeline leakage detection.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
PS
YG

Tuesday July 9, 2019 12:10 - 12:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

12:30 EDT

IDENTIFICATION OF DYNAMIC BEHAVIOUR OF FOREARM FOR ACTIVE CONTROL OF PATHOLOGICAL TREMOR
Pathological tremor is defined as an oscillatory and rhythmic movement of a segment of the body caused by the alternating activation of muscle groups in antagonism between them; a typical pathological condition known as essential tremor, which is the most common form of tremor also having a family character (2-5% of the population) have a characteristic frequency between 5 Hz and 7 Hz, such as Parkinsonian tremor that arises at frequencies higher than 8 Hz. The purpose of this study is to investigate the dynamic behaviour of the forearm induced by the hand movements, measured due to the electromyographic sensors and accelerometers. The relationships of accelerometric and electromyographic signals are compared between a control group of healthy subjects and patients affected by Parkinson disease (PD) and essential tremor (ET). The vibrational phenomena analyzed in this experimental investigation are observed by means of SEMG (surface electro-myographic) sensors placed on flexor and extensor muscle compartment of forearm and accelerometer sensors for the hand vibration with the aim to detect and recognize the dynamic properties of onset of pathological tremor in patients affected by (PD) and (ET). A real-time monitoring and data logger system have been developed and deep described to monitor the tremor: the system allows data monitoring with a portable lightweight microcontroller board based on a CompactRio data acquisition system with a chassis controller module designed for data input, controlling and output generation, powered by 12 Volt battery. The CRio System provides an algorithm to generate functional electrical stimulation signals with different waveforms for control purpose. Experimental measurement data on healthy control subjects are presented. Data are analyzed, and the results are discussed.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
TK

Triantafillos Koukoulas

Dr, Korea Research Institute of Standards and Science

Authors
PF
ZA
IG
VF
CF

Tuesday July 9, 2019 12:30 - 12:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS02 Measur techniq & sens

15:30 EDT

UNCERTAINTY ANALYSIS OF ENVIRONMENTAL SOUND: A STATISTICAL ANALYSIS OF 100 SITES WITH MEASUREMENT OVER SEVERAL DAYS.
In the course of environmental monitoring, instruments are sometimes left at secure locations for more than 24 hours. We have identified approximately 100 sites where road traffic is dominant, with two or more days' worth of data. The sites have an average of four entries (range 2 – 12 days), with about two-thirds sampled on weekdays and the remainder at weekends. Each entry will typically have 288 5-minute samples covering a 24-hour period, comprising equivalent sound pressure levels, together with corresponding percentile data. Such data allow us to examine the variation between 16h (day) 8h (night) and 24h means. In examining these historical data it is clear that the simple arithmetic mean of a 24-hour sample and its standard deviation are very useful indicators of a site's stability. For example, where an arithmetic mean has a low s.d. (measured over 16 or 24 hours) it simply indicates that the data do not fluctuate much, and therefore the 'equalised' or Log average mean will be quite close to the arithmetic mean. A higher s.d. tends to indicate a 'spiky' response, which results in a separation of arithmetic and log averaged means because of the weighting afforded to larger values. In this paper we show that statistical analysis of variance provides a useful general estimate of uncertainty, as it is estimated over replicated mean records at multiple sites. Differentiating between weekdays and weekends gives a lower uncertainty value for weekdays with an overall uncertainty of c. ± 1.5 dB(A).
Moderators
LH

Lars Håkansson

professor, Linnaeus University
AL

Authors
FJ
WW

Tuesday July 9, 2019 15:30 - 15:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS03 Measur uncert in acoust

15:50 EDT

ISO 9614-2 APPLIED TO AN EXTERNAL GEAR PUMP: DETERMINATION OF TYPE A UNCERTAINTY
ISO 9614-X standards enable to determine the sound power level from sound intensity measurements, providing that a physically stationary measurement surface can be defined and that the sound emitted by the source and by other significant extraneous sources are stationary in time. The standards provide the estimated highest values of the standard deviation of reproducibility for each one-third octave band (Type B uncertainty). The "true value" of the overall A-weighted sound power level is expected (at 95% confidence level) to be in the range ± 3 dB or ± 8 dB for the "Engineering grade" or "Survey grade" accuracy, respectively. Such wide ranges, even though acceptable for a standard that can be applied to any kind of source, are often meaningless when the result has to be used for validating numerical simulation or even to compare similar products. If a specific source is under investigation, for instance to detect the performance of noise reduction actions, repeated measurements should be preferred in order to determine Type A uncertainty. This paper presents the results of this approach applied to an external gear pump, showing the reduction of the uncertainty interval width as the number of repeated measurements increases. Acoustic measurements have been performed using the indication given in ISO 9614 part 2 (scanning method), which is probably the most applied methodology due to its simplicity. Results showed that 3 measures seem to be sufficient to have an expanded uncertainty value of repeatability lower than that indicated in ISO 9614-2. A greater number of repetitions would not significantly improve the uncertainty value.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
AL

Authors
BG
CE
PF

Tuesday July 9, 2019 15:50 - 16:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS03 Measur uncert in acoust

16:10 EDT

EXPLORING CURRENT UNCERTAINTIES AND TOLERANCES IN ACOUSTICS MEASUREMENTS AND DATA
Whether it is for a noise compliance assessment or during the design stage of a project with strict and contractually obligated acoustics objectives, one must understand the uncertainties and tolerances in acoustics. Firstly, acoustic data from manufacturers have to be interpreted with the possible swings in their performance and also the allowable tolerances as per some qualification standards. On the other hand, acoustic measurements may be required during commissioning and one face the question by how much a result must diverge from the target to show beyond doubt a noncompliance. The intent here is to summarize current standards and practices of common acoustic measurements with respect to precision and bias (both instrumentally and methodologically) and put it in perspective with the uncertainties/tolerances of available acoustic data to designers.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
AL

Authors
LJ

Tuesday July 9, 2019 16:10 - 16:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS03 Measur uncert in acoust

16:30 EDT

PROGRESS OF CALIBRATION METHODS FOR HIGH SOUND PRESSURE MICROPHONE
High sound pressure microphones are widely used in the measurement of sound explosion and engine noise in the aerospace industry. The measured sound pressure level can reach 160 dB or even higher, which could have a serious impact on human body. The key indicators of high sound pressure microphones are sensitivity, linearity, distortion and frequency response under high sound pressure. In order to ensure accurate and effective measurements, the corresponding calibration methods are needed. This paper reviews the existing calibration methods for high sound pressure microphones, including pistonphone method, pressure-step method and resonant tube method, and explains their respective principles and applications. The pistonphone method is suitable for sound pressure calibration at low frequencies, the step pressure method is suitable for calibration of pulsed sound pressure, and the resonant tube method is suitable for calibration of microphones at a specific frequency point.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
AL

Authors
HL
NF
FX
WM
YJ
ZH

Tuesday July 9, 2019 16:30 - 16:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS03 Measur uncert in acoust

16:50 EDT

REPRODUCIBILITY OF MODAL PARAMETERS USING DIFFERENT EXCITATION TYPES
Experimental acquisition techniques of modal parameters are well-known topics in the dynamic characterization process of steel structures. The objective is to determine the structure's natural vibration properties, which are eigenfrequencies, corresponding mode shapes and damping. Mostly, the experimentally obtained modal parameters are used to verify numerical models, which can be utilized e.g. for overall system vibration simulations. The modal parameters were taken from single measurements and thus, few information about the parameter variances are available. In experimental modal analysis, the choice of the boundary condition (e.g. free or grounded support) as well as the corresponding excitation type (e.g. impulse hammer or shaker) may impact the variance of the obtained modal data. The present article focuses on the difference in reproducibility of modal parameters using an impact hammer and a modal shaker, where measurements are carried out under free/free boundary conditions. The test object is a gear wheel, which first eigenfrequencies occur in a frequency range around 4.6 kHz. During the experimental modal analysis, the frequency response functions are obtained up to 20 kHz. Due to the high frequency range, a 3D scanning laser Doppler vibrometer is used for system response acquisition for all investigations. In a first test setup, statistical variations of a single gear wheel's modal parameters are analyzed and special attention will be payed on the reproducibility of the excitation force using an automated impulse hammer. In a second step, the differences of modal parameters of three gear wheels from one lot are presented. Finally, repeating measurements are carried out using a modal shaker for system excitation and the corresponding modal parameters are compared to the results obtained using an impact hammer.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
AL

Authors
HE
KB

Tuesday July 9, 2019 16:50 - 17:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS03 Measur uncert in acoust
 
Wednesday, July 10
 

10:50 EDT

INVESTIGATION ON THE INFLUENCE OF THE NON-METALLIC SENSOR BASE ON TEST ACCURACY OF VIBRATION ACCELERATION
Acceleration is an important feature used to characterize the vibration of mechanical equipment. In order to reduce power frequency interference, a non-metallic base is usually added to the vibration acceleration test system between the sensor and the measuring point. Three types of non-metallic sensor bases commonly used in the field of ship vibration testing were analyzed in this paper. The transfer function of the sensor and base system was derived by the impedance method, and an analysis was performed to determine how the base stiffness influenced the effective frequency band of the sensor. Through numerical calculation and experimental comparison of three types of non-metallic sensor bases, the relationship between effective testing frequency band and impedance matching was built. The results show that if a non-metallic base is added to the sensor, the test structure will produce additional modes. If the base is less rigid, the frequencies of the additional modes will drop into the effective test frequency band of the sensor, which can seriously impact test accuracy. Selecting a non-metallic base with larger stiffness helps to ensure the validity of the test results.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
WQ
ZY
ZP
ZZ
FD
ZY

Wednesday July 10, 2019 10:50 - 11:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

11:10 EDT

SPHERICAL MICROPHONE ARRAY DESIGN AND VALIDATION: DOUBLE-LAYER VERSUS SIMPLE-LAYER ARRAY
Sound field reproduction in three dimensions is possible using loudspeaker array. To capture spatial sound fields and assess sound field reproduction achieved by different loudspeaker array layouts, accurate microphone antennas are needed. In this context, spherical microphone arrays and spherical harmonics encoding are well suited. Such arrays are able to record frequency and spatial attributes of a sound field. However, the array diameter and the maximum spherical harmonic order it can reach dictate the effective frequency range of a spherical microphone array. A strategy to extend this frequency range is to combine multiple spherical layers in a single array. This means combining several spherical concentric arrays with different diameters. This paper focuses on the double-layer spherical array case. A brief review of double-layer spherical microphone array design is first provided. Then, a crossover and cross-order strategy is proposed to extend the effective frequency range of double-layer microphone arrays. Numerical simulations for multi-frequency plane waves, using double layer spherical microphone arrays are compared to the case of simple-layer microphone arrays.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
GP
BA
GP
GC

Wednesday July 10, 2019 11:10 - 11:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

11:30 EDT

PERFORMANCE COMPARISON OF DECONVOLUTION METHODS FOR SOUND SOURCE LOCALIZATION
Deconvolution can dramatically improve the spatial resolution and the dynamic range of beamforming maps, comparing with the conventional method. However, discrepancies usually exist in the result of different deconvolution methods although they are feed with the same input data. In this paper, in order to find out the most suitable method to deal with a specified problem, a certified analysis criterion is revisited and the performance of three methods CLEAN-SC, FFT-FISTA and FFT-NNLS are examined with a rectangular microphone array. A set of simulations are carried out with different sound source locations, frequencies and numbers. Moreover, the calculated output of forementioned methods are compared with the parameters defined beforehand. In experiments, some loudspeakers are used to validate simulation results. Specifically, due to the difficulty of obtaining the correct acoustic quantities of loudspeakers, the output of Cross Spectral Matrix (CSM) beamforming method is set as the reference so that the behavior of deconvolution methods can be easily investigated. It is shown that the performance of deconvolution methods is dependent on the given conditions of sound sources.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
XY
CL
YT

Wednesday July 10, 2019 11:30 - 11:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

11:50 EDT

SOUND SOURCE LOCALIZATION BASED ON GMMS IN A NECK-BAND MICROPHONE ARRAY MODULE
The sound source localization based on Gaussian mixture models (GMMs) in a neck-band microphone array module is investigated for the localization of the alarming sound. The sound signals are measured by 6 MEMS microphones mounted on the neck-band placed on a mannequin, and the sound source location such as an azimuthal angle or a distance from the sound source is analysed by steered response power with the phase transform (SRP-PHAT) or the GMM classifier using the inter-aural time differences (ITDs) between the microphone pairs and the ratio between direct and reverberant signal components (DRR) which is estimated by measuring cross-correlation ratio (CCR) or coherent-to-diffuse ratio (CDR). The accuracies of the azimuthal angle and the distance from the sound source are comparatively evaluated and analysed between GMM and SRP-PHAT methods. We found that GMM method was better than SRP-PHAT, and the distance as well as the azimuthal angle was well estimated. This technology can be applied to the safety assistance service for disabled people who cannot hear environmental alarming sounds.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
LS
PK
KY
KJ
KB
PH

Wednesday July 10, 2019 11:50 - 12:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

12:10 EDT

REFINEMENT AND IMPLEMENTATION OF A ROBUST DIRECTIONAL ROOM IMPULSE RESPONSE DENOISING PROCESS, INCLUDING APPLICATIONS TO HIGHLY VARIED MEASUREMENT DATABASES
Recent developments in the measurement of directional room impulse responses (DRIR) by spherical microphone arrays (SMA) have led to their extensive use in sound spatialisation. Room reverberation effects can be reproduced in three-dimensional surround sound systems (e.g. Higher-Order Ambisonics) through multi-channel DRIR convolution. However, such measured impulse responses inevitably present a non-negligible noise floor, leading to a perceptible 'infinite reverberation effect'. Further, individual sensor noise and non-stationary measurement artifacts may additionally corrupt the deconvolved impulse response. This paper presents recent work regarding the implementation of state of the art DRIR analysis and denoising techniques and their application to extensive DRIR databases measured across a highly varied collection of spaces. We first review the basic energy decay relief (EDR) analysis and reverberation tail re-synthesis process, before presenting several novel refinements developed throughout the course of this implementation. Finally, an overview of the results obtained both globally and with respect to particular cases (complex architectural volumes, outdoor spaces, etc.) is included in order to further examine the capabilities of the denoising framework.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
MP
CT
WO
NM

Wednesday July 10, 2019 12:10 - 12:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

12:30 EDT

TECHNICAL CHALLENGES TO CALIBRATION OF DIGITAL-OUTPUT MEMS ACCELEROMETERS
This paper addresses technical challenges encountered in calibrating digital-output (DO) MEMS vibration sensors (accelerometers and gyroscopes). The first challenge comes from the traceability of measurements of DO vibration sensors. While the primary and comparison cal-ibration methods of analog-output vibration pickups are well established, no international standard for calibration of DO vibration sensors exists in ISO or IEC. A new calibration sys-tem developed in KRISS for digital-output MEMS accelerometers is introduced. It does not only provide a systematic way of realizing real-time communication with DO MEMS accel-erometers but also to fulfil requisites for the legacy vibration calibration system. A high-speed serial communication prototype for DO accelerometers is shown to be successful for real-time vibration measurement. The traceability of vibration measurement and calibration of digital-output accelerometers is shown to be not feasible without the real-time communication mod-ule properly integrated to the legacy calibration system. Furthermore, this paper unfolds un-expected observations from the DO MEMS accelerometers under calibration, which are never observed from the analogue-output accelerometers. The first one was it that the measured vi-bration frequency from DO MEMS accelerometers was not identical to that of the analog ref-erence accelerometer. It is shown to cause serious amplitude distortion and phase shift of measured vibration signals from the DO accelerometers. A mathematical model is proposed to consider those distortion effects. A simple resampling scheme is shown to enable the distor-tion-free amplitude and phase estimation for the simple harmonic vibration calibration signals. Another useful and realistic approach to the distortion-free amplitude and phase estimation for DO MEMS accelerometers and gyroscopes, referred to the "use of external sampling clock", is also presented with much emphasis. Its performance and significance are compared to those of the proposed resampling method.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
WC

Wednesday July 10, 2019 12:30 - 12:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

15:30 EDT

TEST AND RESEARCH ON ELECTROMAGNETIC EXCITATION CHARACTERISTIC OF ASYNCHRONOUS MOTOR
Electromagnetic excitation is the main source of vibration and noise of asynchronous motor, but the electromagnetic excitation force can not be measured directly, it can only be verified indirectly. In this paper, a 7.5kW asynchronous motor of Y2-132M-4 is taken as an example. Hall sensors are arranged on the inner surface of the stator to measure the magnetic induction intensity by a unique test device, comparing the calculated results with the experimental value，and accuracy of the experiment method is verified. The study provided necessary measures for quantitative analysis of electromagnetic excitation force.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
ZP
FD
ZY
FH

Wednesday July 10, 2019 15:30 - 15:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

15:50 EDT

LOW FREQUENCY AND INFRASOUND ANNOYANCE WITHIN HOMES AND WORKPLACES; EVALUATION USING VALUES IN DBG INSTEAD OF DBA
Legislation exists in most countries to assess noise annoyance by the measurement and analysis of the single global value of dBA. This parameter, however, is inadequate for determining actual annoyance in people, due to the non-auditory effect of hearing low frequency and infrasound in dwellings and workplaces. Some countries propose advanced methods of determining this annoyance, while others propose to use ISO standards; both cases require highly trained acoustics professionals to apply them. Another problem in assessing noise irritation is determining where (in what position) the SLM should be placed within a home or office, since this affects the score of the noise level as a result of the presence of noise modes and resonance. Therefore, it is recommended that measurements be taken in more than one microphone position. The ever-lowering costs of technology and the diffusion of SLM analyzers have been a benefit, as most acoustic instruments now have powerful processing ability. This Paper presents the results of measurements made in enclosures (such as housing and hotel rooms, as well as in offices and workplaces), where it is shown that if the noise level is evaluated in dBG instead of dBA, the position of the microphone inside the enclosure is irrelevant since the sound field in low frequency and infrasound is more diffuse and resonance modes do not affect the ECSPL record very much. It would be necessary only if low frequency and infrasound needed to be analyzed.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
MW
GE

Wednesday July 10, 2019 15:50 - 16:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

16:10 EDT

EXPERIMENTAL EVALUATION OF THE SOUND TRANSMISSION LOSS OF PLANAR STRUCTURES EXCITED BY PLANE WAVES
Correlation between experimental evaluations of the sound transmission loss of planar structures and numerical predictions is a challenging task. A major difficulty concerns the uncertainty related to the acoustic input involved in the experimental procedure. A commonly adopted acoustic load is a diffuse field produced in a reverberation chamber. Shape and size of the reverberation emitting chamber must be defined, according to the desired frequency range, in order to obtain a proper approximation of a diffuse field. However, discrepancies with respect to the ideal diffuse field persists because of the finite size of the chamber. The uncertainty related to the acoustic input employed in the experimental procedure makes a numerical correlation difficult or even unfeasible in case of panels whose sound transmission properties denote high sensitivity with respect to the wavenumber content of the incident field, e.g. double-leaf panels or in-plane anisotropic panels. A possible strategy to overcome such a drawback consists in identifying the actual input acoustic field. Alternatively, the experimental evaluation of the sound transmission loss may be conducted by employing a simpler acoustic load. We propose to excite the specimen with a train of plane waves in order to make experimental assessments directly comparable to results obtained with numerical methods, e.g. the transfer matrix method or the wave finite element method. The train of plane waves is produced by means of a parabolic baffle and a loudspeaker located in its focus. The adopted procedure is exposed and numerical correlations are presented in terms of sound transmission loss for few panels.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
PA
GG

Wednesday July 10, 2019 16:10 - 16:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

16:50 EDT

INFLUENCE OF SLIDING SPEED ON ROUGHNESS NOISE
This article presents an experiment and numerical simulation on friction noise. The noise emitted by a solid rubbing on a rough surface, also called roughness noise, results from a complex interac-tion between microscopic asperities of both surfaces. It is characterized by a wide band spectrum, a low noise levels and a weak mechanical interaction. The level is controlled by several external parameters such as surface roughness, normal load and sliding speed. The purpose of our study is to understand the evolution of roughness noise versus sliding speed. To achieve this goal, an ex-perimental approach and numerical simulation have been used and the obtained results highlight the law between sound level and sliding velocity. The main conclusion of the study is that noise level versus sliding speed follows a power law with an exponent about 3/4. Keywords: roughness noise, sliding speed, vibratory level
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
MA
AL

Alain Le Bot

Dr, Ecole centrale de Lyon - CNRS

Wednesday July 10, 2019 16:50 - 17:10 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

17:10 EDT

ACTIVE CONTROL USING DYNAMIC-RATE SAMPLING
Variable-rate sampling is accepted as a good method for improving the measurements of sound and vibration produced by rotating machinery often referred to as order based sampling. Adaptive active control of the sound and vibration of this same machinery, though, is commonly performed with fixed-rate sampling and processing. During instances where tonal content being controlled is varying in frequency, a delay in convergence results from the mismatch created between the control filter sampling rate and the changing center frequency of interest. This mismatch can be eliminated with dynamic sampling triggered by a tachometer signal. A comparison of fixed- and dynamic-rate active noise control is presented to compare convergence, tracking performance, and computational load for an active noise control application.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
MD
LT

Wednesday July 10, 2019 17:10 - 17:30 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

17:30 EDT

APPLICATIONS OF MIMO DIGITAL ADAPTIVE CONTROL TO HIGH LEVEL ACOUSTIC TESTING
Recent developments in high-level acoustics testing apply to Direct Field Acoustic Testing (DFAT) and traditional Reverberant Chamber Acoustic Testing (RCAT). Both testing methodologies benefit from the introduction of narrowband and Multiple Input/Multiple Output (MIMO) adaptive digital control. Paper discusses advantages of using modern MIMO control technology in DFAT and RCAT. MIMO DFAT control uses multiple independent drive signals to control the acoustic field's response Nth fractional octave spectra. Multiple drives are sent to multiple acoustic exciters or loudspeaker stack subsystems via their respective amplifiers and associated signal conditioning. Multiple control microphones are placed at points within the resulting acoustic field. Control is performed in the frequency domain by determining the control-response Spectral Density Matrix (SDM) from the vector of microphone responses using FFT processing. Iterations of this adaptive optimal control process update the vector of drive signals to cause the respective microphone's PSD, sound pressure level (SPL) spectra, and the relative coherence and phase between them, to match the corresponding elements of the test specified control-reference SDM. The control-reference SDM represents the desired acoustic field with their specified PSD magnitudes for each microphone location as well as the relative phase and coherence between each pair of control microphone responses. Effectively, adaptive optimal method controls the acoustic-field response levels at each control microphone location, as well as the relative coherence and phase between each pair of microphones, to meet its individual requirement based on the acoustic-excitation it receives from all the speakers or acoustic modulators as a result of the vector of independent drive signals, as their drive SDM is updated. Control updates to the drive SDM account for the initial control errors and unavoidable nonlinearities. Result can be a nearly incoherent acoustic field at the higher frequencies, with minimum variation between control microphones.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
UM

Wednesday July 10, 2019 17:30 - 17:50 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys
 
Thursday, July 11
 

09:20 EDT

OPERATING DEFLECTION SHAPE ANALYSIS OF A REVERSIBLE VIBRATORY PLATE
Light road construction machinery such as manually operated reversible plate compactors or reversible vibratory plates are used for compacting sand, gravel, rock fill soil, etc. with the aid of vibration. The purpose of the vibration excitation of the ground is to produce pressure waves that penetrates the ground layers to overcome the resisting friction between the soil particles, in order to reduce the soil porosity and permeability. During compaction the ground is dynamically excited via a compactor's bottom plate. However, the actual spatial dynamic behaviour of a compactor's bottom plate during operation may not be known. To increase the knowledge concerning the spatial dynamic behaviour of a compactor's bottom plate during operation; a reversible plate compactor whose bottom plate has been considered as a rigid body in its design has been investigated. An increased knowledge concerning the dynamic behaviour of compactor's bottom plate during operation is likely to enable a further improvement in the design of reversible vibratory plates concerning their performance, vibration exposure of operator, etc. To acquire knowledge concerning the dynamic behaviour of the bottom plate of a plate compactor during operation spatial measurements of its acceleration response have been carried out on it during operation on rubber mats. Operating deflection shape analyses of the bottom plate have been carried out based on both power spectral density estimates and power spectrum estimates, etc. of the recorded acceleration responses of it. Also, the fact that the frequency of the vibration excitation of the reversible plate compactor varied slightly and thus induced a frequency modulated vibration response of the plate was considered in the ODS analysis. The analyses indicates different dynamic behaviours of the bottom plate depending on the operation of the reversible vibratory plate, i.e. if it operates in idle, reverse motion or forward motion.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
HL
PA
MS
JT

Thursday July 11, 2019 09:20 - 09:40 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

09:40 EDT

EXPERIMENTAL STUDY ON THE INFLUENCE OF RUNNING PARAMETERS ON VIBRATION CHARACTERISTICS OF ROLLING BEARINGS
In this paper, the vibration characteristic test rig of rolling bearings is designed and built; the vibration characteristics of rolling bearings are tested in different operating parameters, such as grease parameter, clearance range, pre-tightening force and load characteristics; the influence law and degree of operating parameters on bearing vibration characteristics are analyzed; the relationships between running parameters and vibration characteristics of rolling bearings are preliminarily established. The research results of this paper have certain engineering guiding significance for improving the installation process, optimization and improvement on the running reliability of rolling bearings.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
YZ
HF
HS
ZL

Thursday July 11, 2019 09:40 - 10:00 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

10:00 EDT

VIBRATION INDUCED FATIGUE LIFE ESTIMATION BASED ON NON-STATIONARY STOCHASTIC PROCESSES SEGMENTED TO PIECEWISE STATIONARY SEGMENTS
At excavations of quarries, construction sites or in mining, etc. articulated haulers are commonly used for the transportation of material. Thus, articulated haulers are exposed to a diversity of different worksites that all will load them differently. With a continuously growing market and added exhaust emission regulations, the machines need to be continuously optimized to meet durability and weight (fuel efficiency) requirements. In the structural design of any given component in an articulated hauler the assumed loads used will reflect on its design. However, it is rarely the case that the loads used in the design procedure strictly represents the dynamic loads a hauler will be subjected to. As a result, the machines are generally oversized. To address the issue of oversized components, a statistical approach for the estimation of their fatigue life may be utilised. With the aid of power spectral density estimates of a components dynamic loads in combination with a finite element model of the component its vibration response in terms of power spectral densities may be estimated. Based on the vibration response spectra the component's fatigue life may be estimated assuming that the components dynamic loads may be considered as weakly stationary stochastic processes. To investigate if the dynamic loads used for fatigue life estimation may be considered as weakly stationary stochastic processes; stationarity tests have been carried out as well as estimates of the kurtosis and the mean square value as a function of time have been produced. The results indicates that the dynamic loads may not be considered as weakly stationary stochastic processes. Furthermore, by segmenting the dynamic load time series into segments that can be considered as weakly stationary the estimated fatigue life seems to decreases slightly if compared to the case when assuming that the dynamic loads are weakly stationary.
Moderators
LH

Lars Håkansson

professor, Linnaeus University
CH

Claes Hedberg

Professor, Blekinge Institute of Technology
MM

Authors
HL
JE
DR
AM

Thursday July 11, 2019 10:00 - 10:20 EDT
Westmount 2
  T01 Ac. meas. & instrum., SS01 Snd & vibr measur & analys

10:40 EDT

IMPACT OF VIBRO-ISOLATION OF TECHNICAL EQUIPMENT ON STRUCTURE-BORNE NOISE IN LIVING AREAS
Structure-borne low-frequency noise in buildings is generated by technical equipment such as fans, pumps, compressors that are not well vibration isolation. Well-designed vibration isolation of vibrating sources can effectively reduce the transmission of energy into surrounding structures and acoustically protected spaces. The low-frequency noise even in far enclosed spaces can increase the sound pressure level due to standing waves. The energy of the low-frequency waves can have a negative effect on humans, especially in the immediate vicinity of the sources. The effects of low-frequency noise energy on the residents are manifested as head pressure, irritability, migraine, fatigue, awakening, insomnia, stress, depression. The present paper investigates the conditions for reducing the transmission of structure-borne sound from vibration sources of the technical equipment of buildings into residential areas where this noise was manifested as audible tone components of 36 Hz and 49 Hz with values up to 30 dB higher than the background in the protected rooms. The solution is based on the theoretical knowledge and methodology of the transmission of vibro-sound energy and measurement of vibration in rooms and along the path of transmission, as well as on sound measurements which were also performed. For the sound and vibration measurements the FFT analysis was used. The transmission loss of building technical equipment isolators was measured and the results were compared with theory. Finally, this paper suggests some effective measures which can have impact on the reduction of the unwanted vibro-sound energy and on the health of the people and environment.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
CO
ZS
HB
TJ

Thursday July 11, 2019 10:40 - 11:00 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS04 Instr fr snd & vibr measur & anl

11:00 EDT

CHARACTERIZATION OF A NONLINEAR SOUND ABSORBER AT LOW FREQUENCIES AND HIGH SOUND LEVELS
The objective of this work is to develop identification techniques to characterize nonlinear acoustic loads. These nonlinear acoustic loads are here considered as a one-port acoustic system, analyzed at low frequencies and for increasing excitation levels. A specific setup of impedance tube named "Short Kundt's Tube" was built to reach high sound levels at low frequencies. Two approaches, developed in the frequency domain, are discussed in this work. The two approaches require a single acoustic pressure measurement inside the Short Kundt's Tube, and a calibration of the Short Kundt's Tube acoustic source from a set of known (linear) acoustic loads. The first approach is defined as a linearization method and gives access to the acoustic impedance which is excitation level dependent. The second one is based on a nonlinear model able to characterize energy transfer to higher harmonics. It is defined as a scattering matrix linking the harmonic components of the input and output pressure wave amplitudes. These techniques are applied for the study of two different nonlinear vibroacoustic absorbers based on the concept of targeted energy transfer.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
VM
CR
BS

Thursday July 11, 2019 11:00 - 11:20 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS04 Instr fr snd & vibr measur & anl

11:20 EDT

MEASURING THE WAVE SHAPE AND WAVE PROPAGATION SPEED OF TWO IMPACTING RODS OF ARBITRARY CROSS SECTION AND MATERIAL
Impacting rods are used both in experimental set-ups such as the Split-Hopkinson pressure bar and in practical applications as the percussion driller. Understanding the wave propagation phenomena is crucial to improve these devices. In this contribution, a single-hit test rig to measure the wave shape and propagation of axially dependent impacting rods has been set up. It consists of a pneumatic gun that accelerates a piston which hits a second rod at known initial velocity. The impact is recorded by a high-speed camera that leads, in turn, to a better insight of the hit and enables the interpretation of the measurement results. At the rod, up to eight strain gauges are attached which measure the stress wave at different positions and at very high frame rates at the same time. Thus, the evolution of the stress wave shape and the wave propagation speed can be determined. The main challenge in measuring is to achieve a good balance between a high bandwidth of the signal, which is necessary to attain sharp wave shapes and acceptable noise. The obtained results are repeatable and in good accordance with a numerical model, that has been implemented based on the Wave Finite Element Method.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
BJ
SW

Thursday July 11, 2019 11:20 - 11:40 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS04 Instr fr snd & vibr measur & anl

11:40 EDT

MEASUREMENT DEVICE FOR NEAR-BIT DYNAMIC PARAMETERS WHILE DRILLING
In the process of oil and gas drilling engineering, measurement of downhole parameters while drilling is very important. Especially for the drilling of multi-branch wells and horizontal wells, the downhole condition is more complex, which leads to the increase of the incidence of drilling accidents. Accidents such as damage of drill tools and sticking often occur in the process of oil drilling. The occurrence of these accidents is closely related to the real-time engineering parameters of drilling. Therefore, real-time monitoring of downhole torque, drill-fluid pressure, rotation rate, annular pressure, vibration and other parameters are of great significance for well drilling and the prevent of accidents. Here we developed a kind of near-bit measurement system for dynamic parameters while drilling, which can measure the torque and weight on bit, pressure of drilling mud, rotational speed and triaxial vibration in real time while drilling. Real-time analysis of the downhole data can be used to evaluate the performance of the downhole tools and prevent drilling accidents. The paper briefly introduced the work principles, composition and application of the system. Also, this paper will highlight the technical development and present helpful case histories and recommendations.
Moderators
LH

Lars Håkansson

professor, Linnaeus University

Authors
JH
LN
TX
ZQ
ZB
GW

Thursday July 11, 2019 11:40 - 12:00 EDT
Westmount 2
  T01 Ac. meas. & instrum., RS04 Instr fr snd & vibr measur & anl
 

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CIRMMT—McGill University
Clock Tower Pier, Old-Port of Montreal
École de technologie supérieure (ÉTS) - Batiment A
École de technologie supérieure (ÉTS) - Batiment E
Exhibition Hall (St-Laurent 1&2)
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  • Accompanying Person Program
  • Business Meetings
  • Exhibition and functions
  • Lunch & coffee breaks
  • Plenary Lectures
  • Scientific Visits
  • Socials Events
  • T01 Ac. meas. & instrum.
  • T02 Act. noise & vib. cntrl.
  • T03 Aero… aircrft noise & vibr.
  • T04 Environ. & commun. noise
  • T05 Phys. ac. ultrasnd. & wave prop.
  • T06 Industr. and occup. Noise & vib.
  • T07 Struct. dyn. & nonlin. vib.
  • T08 Mat. for noise & vibr. cntrl.
  • T09 Audiology… & comm. in noise
  • T10 Sig. Proc. & nonlin. mthds.
  • T11 Room & build. acoustics
  • T12 Underwater & marit. noise
  • T13 Acoustical education
  • T14 Musical acoustic
  • T15 Road & rlway noise & vibr.
  • Presentation Format
  • Oral Presentation
  • Poster Session
  • Peer-Review Status
  • Non-Reviewed
  • Peer-Reviewd
  • Award Applicants
  • IRSST Award
  • Lighthill & IRSST Award
  • Lighthill Award
  • No