Conceptual optimal design of modular car product families using simultaneous size, shape and topology optimization

Structural optimization of a single product is in this paper extended to optimization of a family of products where size, shape, and topology optimization are accomplished simultaneously. The design variables are either variables used only locally in a product or variables globally shared among all or several of the other products in the family. A mathematical formulation for optimization, based on classical performance and cost measures such as compliance and mass, is given. A comprehensive product family optimization application is discussed, where three products exposed to seven load cases each, are studied. These are existing products. The split into modules is governed by the true commonality between components used for manufacturing of these products. An accurate mass distribution in the products has been found to be of great importance to be able to simulate the different load cases as correctly as possible. The methodology described in this paper can serve as a tool for investigations of what the reduction of some typical optimal properties of a specific product will be if some components have to be shared by other similar products. Another important aspect of this methodology is that the optimal topology and load transfer through a single product can be compared to what is optimal if the product has to be a member of a product family.