Abstract: The highly nonlinear nature of the contact problem makes it difficult to achieve high material utilization of the assembled structure and uniform stress distribution at the contact interface simultaneously. Most existing topology optimizations that consider the stress distribution at contact interface require relatively complicated processing and large computational resources. To address this issue, the idea of collaborative optimization of assembly structure and material stiffness in contact problem is proposed, and the sequential optimization strategy of topology optimization followed by material stiffness optimization is adopted. That is to say, an assembled structure with high material utilization is obtained through topology optimization first, and then it is used as the input of followed material stiffness optimization to achieve a uniform stress distribution at contact interface through material stiffness optimization. This idea features the direct application of established mature topology optimization methods without complicated processing to deal with the contact nonlinearity. Further, the collaborative optimization model of topology and material stiffness in contact problem is developed, and a Von Mises stress-based collaborative optimization method of topology and material stiffness is proposed. Sensitivity analysis is not required during the optimization process. Finally, the feasibility and effectiveness of the collaborative optimization of structural topology and material stiffness are verified based on a typical elastic-rigid assembled structure and an elastic-elastic assembled structure.

Key words: topology optimization, material stiffness optimization, collaborative optimization, contact stress