SOME RESULTS ON OPTIMAL TOPOLOGY DESIGN OF TRUSS WITH UNILATERAL CONTACT CONSTRAINTS

The optimal topology design of truss structures concerning stress and frictionless unilateralcontact displacement constraints is investigated.The existence of ununique optimal solution under contactgaps is found.This shows that the contact conditions have an effect on structural topology,and different ini-tial contact gaps may lead to different structural topologies.To avoid the singular optima in structural topologyoptimization in multiple loading cases,an e-relaxed method is adopted to establish the relaxing topology opti-mization formulations.The problem is solved by means of a two-level optimization method.In the first sub-level,the solution of the frictionless unilateral contact problem is obtained by solving an equivalent quadraticprogramming.In the second sublevel,topology optimization of truss is carried out by an ε-relaxed method.The validity of the method proposed is verified by computational results.