Combined interface shape and material stiffness optimization for uniform distribution of contact stress

Contact stress distribution is sensitive to the interface shape and the material stiffness. A combination of the interface shape and the material stiffness is investigated to obtain a uniform contact stress distribution. A combined interface shape and material stiffness optimization method is developed based on the evolutionary optimization techniques. The uniformity of the contact stress is represented by its variance and is defined as the objective function. The gap distance and the Young's modulus are treated as the design variables of the shape optimization and the material stiffness optimization, respectively. A fixed optimization sequence, which is the material stiffness optimization followed by the interface shape optimization, is adopted. The effectiveness of the combined interface shape and material stiffness design on improving the uniformity of the contact stress is verified based on two cases. Additionally, the undesired nonsmooth transition of the contact stress after only the material stiffness optimization could be alleviated during the followed interface shape optimization process, thus a smoother and more uniform distribution of the contact stress could be achieved.