A numerical optimization method is performed on a fictive but realistic porous material with a continuous through the thickness gradient of porosity. The porous material is made of ordered unit cell with parametric geometrical dimensions. The Johnson-Champoux-Allard-Lafarge parameters of any geometrical unit cell is computed by FEM method. These parameters are used as input for the prediction of the acoustic properties of the graded material. A conjugate gradient algorithm eventually creates the best micro-geometrical continuous gradient with the optimal acoustic absorption. The acoustic performances of the continuous graded material are discussed with respect to the optimized non-graded material. All the investigations are made on the same unit cells. The numerical results show a significant improvement of the targeted acoustic absorption when introducing the gradient of properties.
