Optimal topology design of steel–concrete composite structures under stiffness and strength constraints

This study presents a three-phase topology optimization model and an effective solution procedure to generate optimal material distributions for complex steel–concrete composite structures. The objective is to minimize the total material cost (or mass) while satisfying the specified structural stiffness requirements and concrete strength constraints. Based on the Drucker–Prager criterion for concrete yield behaviour, the extended power-law interpolation for material properties and a cosine-type relaxation scheme for Drucker–Prager stress constraints are adopted. An enhanced aggregation method is employed to efficiently treat the large number of stress constraints, and the optimal topology is obtained through a standard gradient-based search. Several examples are provided to demonstrate the capability of the proposed optimization method in automatically finding the reasonable composite layout of steel and concrete.

► A three-phase topology optimization for steel–concrete composites is presented.
► A cosine-type relaxation scheme for D–P stress constraints is adopted.
► An enhanced aggregation method is proposed to treat large-scale stress constraints.