Mechanical Properties and Collaborative Design of Triply Periodic Minimal Surface Structures with Variable Density and Variable Direction

This paper separately investigates the effects of variable density and variable direction design on the quasistatic compressive response of triply periodic minimal surface (TPMS) structures and subsequently proposes an integrated optimization strategy. First, the variable density design is investigated. The elastic modulus remains nearly constant at 295 MPa across all gradients, but increasing the linear gradient coefficient from 0.5 to 1.5 reduces the yield strength and plateau stress by 13.4% and 11.3%, respectively, while total energy absorption varies by merely ±1.34%. Then, the variable direction design is analyzed. Rotating the lattice to 45° increases the elastic modulus by 39.6% to 416 MPa and raises the specific energy absorption by 43.6% to 64.2 J/g, which confirms that load capacity and load uniformity can be independently adjusted. Based on these findings, a series of TPMS structures combining variable density and variable direction is constructed. In the three‐point bending test, the peak load of the 2D optimized beam increased by 27.79% compared with the uniform beam. However, for the supporting beam, the peak load and energy absorption of the 3D optimized beam improved by 15.36% and 19.83%, respectively.