Mechanical property is an important parameter of friction material as it influences contact distribution (tribological and thermo-mechanical behavior), dynamic behavior (and then squeal propensity). Due to the process, the percentage of porosity in the volume is near 10%. So, a friction pad has been characterized by a topographical study using X-ray. This step permits to obtain some information concerning the porosity. In a second step, a simplified pin-on-disc is modeled using finite element method considering initially homogenized friction material and secondly heterogeneous friction material including the pores. The pore distributions are generated using a representative random fields technique. The introduction of pores shows clearly some differences on dynamical behavior between homogenized and heterogeneous materials consideration.