Abstract
The CarIndustry is facing problems such as global warming and air pollution. Car Makers must reduce CO2 emissions by making lighter vehicles.
In the development of large plastic parts such as instrument panels, we evaluate rigidity and heat resistanceusing CAE in the early design stages to determine the best shape of any given part. Rigidity is evaluated as deflection to evaluate how firm a part is under hand pressure. Heat resistance is evaluated as thermal deformation in hot weather, summertime conditions. In our present process, we design the shape of the parts according to the deformation and stress obtained from the rigidity and heat resistance CAE. However, the different evaluations require that different areas be strengthened. And we thought that further lightening of the parts would be made possible if we could satisfy both requirements at the same time.
We have now established two techniques to design the structure of plastic parts using topology optimization. Firstly, we applied the topology optimization technology to thermal deformation in a heat resistance evaluation. Secondly, we developed a technique to decide the strength distribution ratio based on the results of the topology optimization of both rigidity and heat resistance. By topology optimization using this strength distribution ratio, it was possible to calculate the areas to be strengthened to meet both requirements.
Applying this new technique to the instrument panel, we gained a clear understanding of the strength necessary for both requirements,and the instrument panel, while maintaining both rigidity and heat resistance requirement, was lightened by 20%.
Keywords: plastic parts,CAE, rigidity, heat resistance, topology optimization