The paper provides information about the reliability and accuracy of the results of nu- merical simulation of stress waves in solid deformable environment. The problem of elastic reflection of stress waves from the free surface of the plate. The task is implemented using the finite element method in movements. The comparison is made with results of the analytical solution at the front of the flat longitudinal wave. The studied problem is presented in the form of an infinite plate

differential equations in partial derivatives, the problem with the initial conditions, the Cauchy problem, mathematical and numerical modeling, the principle of pos- sible displacements, the homogeneous algorithm, finite element method, transient wave of voltage, an explicit two-layer scheme and the analytical solution, comparison, reliability, wave front, the Delta function pulse effect in the form of a triangle, a long-playing record.