Technical Papers and Presentations

Nowadays, to go along with sustainable development and for cost matters, automotive heat exchangers are built with less and less aluminum and the process costs are being cut. However, the real mechanical response is a plastic shakedown, which is why we need to model the cyclic response as well as to find a fatigue criterion. A finite element model was developed using COMSOL Multiphysics to describe the cyclic behavior of the aluminum tubes. A time dependent mechanical simulation was conducted with a thermal loading introduced from an experimental Infra-Red (IR) film which contains the whole thermal history of the heat exchanger during a thermal shock. The behavior law takes into account the plastic hardening. The originality of our study is the use of a measured external thermal field from a file, entered in our model, which avoids us doing a thermal simulation where the convective coefficients are very difficult to identify, but also the implementation of a Chaboche type elasto-plastic law with cyclic hardening and an energy based fatigue criterion for plastic shakedown.