Numerical modeling of particle embedment during solid particle erosion of ductile materials

Abstract

Particle embedment may occur in erosion testing, abrasive jet machining, blast cleaning and other industrial processes in which high speed impact of particles on relatively ductile targets occurs. It may strongly affect erosion rates, and lead to undesirable changes in surface roughness. Three-dimensional smoothed particle hydrodynamics (SPH) simulations were used to simulate particle embedment when 219.2µm and 362.9µm angular silicon carbide particles impacted a strain and strain rate hardening 6061-T6 aluminum alloy target under various process conditions. The models were assessed by comparison with measured embedment. Analysis of the results showed the following: (i) once the value of the effective friction coefficient between the substrate and the abrasive was determined by comparing predicted and measured embedment at one set of process conditions (particle velocity, size, angle of attack), the same friction coefficient could be used in models of all other combinations of process conditions to correctly predict embedment. (ii) Consistent with a previous simplified rigid-plastic analysis of idealized rhomboid particles impacting a polymer target, the static frictional force occurring after the maximum depth has been reached, the particle orientation and the impact angle all strongly affected embedment. Unlike the previous simplified model, the present model considered local strain rate and strain hardening, making it applicable for ductile metal targets. (iii) Consistent with some, but not all, reports in the literature, embedment at a given velocity increased with particle size. (iv) For a given particle size, embedment increased with incident velocity. (v) A critical minimum velocity below which embedment would not occur was predicted. The trends were discussed in terms of embedment mechanisms and particle impact kinematics. Overall, the work demonstrates that SPH methods can be used to provide insight into complex solid particle erosion phenomena.