This thesis is composed by an experimental part and numerical part, aimed at contributing to a better knowledge of the behavior of plastic parts under different loading conditions. The study is intended to validate a FE model for simulating exterior plastic components of car especially the A-decor and plastic clips in the context of thermal and static load analysis. From the comparison of numerical and experimental results in the terms of thermal and static deformation of the A-decor, it is concluded that both thermal and static behavior of the A-decor in test can be well captured by means of proposed plastic clips connection model. Furthermore the squeak and rattle analysis method is extended to predict the behavior of plastic parts under different loading conditions.