A computational framework for predicting the adhesion strength of bonding in cold spray

A computational method is proposed to model bonding of powder particles in cold spray capable of predicting the adhesion strength. The method relies on a strain-like history variable named bonding parameter developed in our previous research [1-2] that is based on the commonly held view that bonding occurs due to large plastic strains occurring at extreme rates. It contains two material constants, the critical surface adhesion energy, and the critical surface adhesion energy rate. We complement the model with a semi-empirical evolution law for adhesion strength on bonding boundaries. The strength evolution model interacts with the bonding evolution model and is coupled with the bonding parameter. The model is implemented numerically within a material point method (MPM) in a way that effectively eliminates spurious mesh dependence and captures complex phenomena such as jetting. Results are very encouraging and exhibit desirable agreement with known experimental data such as critical bonding velocity, adhesion strength, and deformed particle/substrate shape. [1] Reza Hirmand, Jonathan Tang, Hamid Jahed, A numerical modelling framework for impact-induced bonding of powder particles in cold spray, in submission [2] Jonathan Tang, Predictive model of impact-induced bonding in cold spray using the Material Point Method, Master’s Thesis, University of Waterloo, 2021