Mechanical behaviors of BCC lattices under combined compression-shear loadings

The deformation modes and energy absorption of BCC (Body-Centered Cubic) lattices subjected to uniaxial compression have been widely studied. However, their mechanical behavior under complex loading conditions, such as combined compression-shear, remains unexplored. This gap limits confidence in applying BCC lattices to scenarios involving such complexities. This study investigates the mechanical behavior of BCC lattices under combined compression-shear loading conditions. The Fused Deposition Modelling (FDM) process with thermoplastic polyurethane (TPU) filaments were used to fabricate BCC lattice specimens. Quasi-static tests on lattice specimens were conducted at loading angles of 15°, 30°, and 45°, as well as under uniaxial compression at 0° for comparison. The deformation histories and force-displacement curves were examined to identify the deformation modes and analyze energy absorption characteristics. Two deformation modes distinct from those observed under uniaxial conditions were experimentally revealed at the varied loading angels. A finite element model was developed to numerically investigate the characteristics of normal and shear forces, as well as the influences of truss diameter and shear angle on the performance of BCC structures under combined compression-shear conditions. The findings presented in this study provide valuable references for the feasibility and reliability analysis of BCC lattice applications under compression-shear conditions. • BCC lattices under combined compression–shear were studied experimentally and numerically. • Two deformation modes were identified in BCC lattices under combined compression–shear. • Loading angle affects compressive and shear forces and energy absorption of BCC lattices. • The effects of truss diameter and shear angle have been investigated numerically. • The yield envelope of BCC metamaterial has been developed.