Modelling cold spray splat morphologies using Smoothed Particle Hydrodynamics

Abstract

The small scale, short duration and hostile environment for instrumentation presented by cold spray coating makes experimental observations challenging, and therefore requires computational models capable of capturing the splat formation process. Current coating models are dominated by the Finite Element Method (FEM); whilst this has lead to significant improvements in understanding, the method is limited due to the reliance on a mesh coupled with the significant strains and strain rates involved. Eulerian methods have also been applied but retrieval of material histories and accurate interface tracking remains challenging. The Smoothed Particle Hydrodynamics (SPH) method is a meshless method that combines the advantages of FEM and Eulerian approaches. The current work extends the work of applying SPH to solid mechanics with heat conduction, improved tensile stability corrections and a novel zero impedance boundary. Solver performance is increased with the application of the multi-threading capabilities of the C++ 11 standard. The development of the SPH solver is described, validated and benchmarked against known analytical and experimental test cases. An in-depth investigation of parameters affecting splat morphologies is performed. Finally, a model of a coating formation process involoving multiple feedstock impact events is described and analysed in order to demonstrate the capabilities of the newly developed solver.