A CAD-based optimal design procedure is developed and illustrated with an application to a problem of tire contours. One of the main features of the procedure is to describe the design directly on a parametric CAD model, instead of the nodal information of a finite element mesh. This is a very important advantage over a FE-based approach, often used in the literature. Although one example of a tire cord design is demonstrated, it may be applied equally well to other designs of such as a tread, sidewalls, and so on.
In order to improve durability of a tire, strain energy density is considered as an objective. Design variables are taken from geometric parameters representing the shape of tire carcass. Two formulations are considered: Minimizing strain energy density for improving durability, and minimizing the cord length to reduce cost while the region of the cord end maintains below an initial value of strain energy. Solutions converge very well, and the final results seem very satisfactory.
Using the CAD API (Application Programming Interface), an interface program between CAD modeler and analysis solver is developed. It makes it possible for a designer to follow the menu to define an optimal design problem and solve it without intervention for mesh generation, analysis and optimization. The feasibility of the approach is shown for the optimization of the tire cord problems noted above. The tire model being taken very simple, however, it needs to try more refined models for analysis before to be used in real practice.