Computer modeling of coating thickness, heat transfer and thermal residual stress in spray deposition processes

A transient three-dimensional computer model has been developed to describe macroscopic heat transfer and stress processes during the spray deposition of a coating onto a substrate of complex shape. The model uses a finite element based enthalpy approach to predict coating solidification and thickness, and both coating and substrate temperatures. The model includes the effect of contact resistance between the substrate and the coating. The model uses a displacement based finite element approach to predict stresses in both the coating and the substrate.;The model is a significant advance over previous models in that it can be applied to substrates of arbitrary shape and can include the effect of the shadowing of one part of the substrate by another part. It is restricted to the application of thin coatings, where the growth of the coating does not significantly affect the geometry of the substrate. Thus, the model is applicable to plasma spray, HVOF and PVD-type systems. It is less applicable to processes that involve the deposition of large quantities of material, such as spray-forming.;The model uses a macroscopic continuum approach wherein the microscopic structure of the coating enters as effective physical, thermodynamic and transport properties. These properties are taken as inputs to the model. The calculation of the properties from the microstructure of the coating is considered to be beyond the scope of the present thesis.;The model is written in FORTRAN and accepts mesh data from a simple text file that can be generated by most commercial mesh generation programs. Similarly, output of model results is via a text file that can be interfaced with commercial post-processing packages.;There is no direct experimental data with which to compare the results of the model. However, the consistency of the model has been tested against a number of simplified test cases, analytical solutions and the predictions of other computer codes.