Design of 3D orthotropic materials with prescribed ratios for effective Young's moduli

► A new topic on 3D orthotropic material design is presented in this paper. ► The material is designed to satisfy prescribed ratios for three Young's moduli. ► The overall material integrity is maintained by maximizing the bulk modulus. ► Lagrangian function in the form of strain energy is solved to find the optimum. ► Examples of various orthotropy ratios demonstrate convergence of solutions.