This paper is motivated by the need to predict deformation behavior of an automotive thermoplastic fender during its residence in e-coat paint bake oven where it is heated by convective currents from blowers. Part - 1 [
1
] of this paper, presented a FEA methodology to model the behavior of thermoplastic fender during ecoat bake. Additionally a multiphysics computational procedure to include effect of temperature and stress history was also proposed to enhance the accuracy of the solution.
In this paper, we focus on the prediction of temperature history and its influence on fender deformation. Towards this, we present a two-stage thermo-mechanical simulation procedure utilizing CFD and FEA to model the ecoat bake process. While the procedure can model the heating of the fender by convective currents from blowers using CFD, the required flow field data of the ecoat oven is highly confidential. Hence, we also study the influence of approximating the temperature field on displacement prediction.
To study the influence of approximating the temperature field on displacement prediction we considered three different temperature inputs to the stress analysis. In the first case, we employed results of the transient thermal simulation as input. For the second case, we used temperature profile obtained from thermocouple measurement and for the third most simplified case; we assumed a linearized profile, which captures the peak temperature and the correct residence time. We had run this simulation on two distinct real life fender geometries.
The comparative simulation data indicates that the approximation of the temperature has lesser effect on the fender with uniform thickness as compared to a fender with thickness variation and relatively higher mass. Thus, the two-stage procedure proposed in this paper can be simplified in the initial design phase. However, for production level parts that typically have thickness variation, the comprehensive approach utilizing CFD and FEA is recommended.