Modeling of damage from multiple impacts by spherical particles

Solid-particle erosion (SPE) is studied by constructing finite-element (FE) models of elastic spheres of steel and alumina impacting normally on the surface of a kinematically hardening, elastic-plastic material, such as copper. The full effects of the contact surfaces and the impact dynamics are included. An earlier phase of this study modeled multiple, coincident impacts with two-dimensional (2D) analysis, in which damage computations by strain-life, cyclic plastic work (CPW), and continuum damage mechanics (CDM) methods were shown to be roughly equivalent. Here, it is shown that a 2D model is incorrect for non-coincident impacts; a 3D FE analysis is necessary. A stochastic model of multiple impacting spheres is developed, which can describe spatial and temporal accumulation of damage. Finally, erosion rates are estimated by extrapolating the average rates of damage accumulation in the outermost layers of the target material to a value of 1.0.