The article presents a method of developing a FE model for prediction the cutting depth of inhomogeneous materials - polymeric composites reinforced by fibers. A nonlinear dynamic finite element model has been developed in order to explain the behavior of the process. The basic task was to define the interaction between the tool and a workpiece during impacting a single particle into surface of workpiece. The model takes into account an orthotropic material and a procedure of bonding between layers. The performed experimental research allowed to determine the penetration depth of single abrasive particle depending on pressure of water jet. It enables to compare experimental and simulation results and to create a mathematical predictive model of erosion depth.