Topology optimization of truss-like continua with different material properties in tension and compression

The literature on the topology optimization of truss-like continua has relatively few publications that look at the problem of structures with different material properties/behaviour in tension and compression. After reviewing the literature on optimality criteria, ground structure approach, growth method for truss structures, SIMP, homogenization and heuristic methods of topology optimization, a method is proposed in this paper which consists of identifying all negative (compressive) parts of a structure; modifying their modulus of elasticity; changing their material properties to orthotropic, modifying the stresses or strains and satisfying the optimality criterion of a constant stress/strain ratio between the tensile and compressive parts of the structure. The validity of this technique is demonstrated on several examples, including comparisons with results by other methods.