Mechanical performances of novel cosine function cell-based metallic lattice structures under quasi-static compressive loading

This study proposes a novel lattice structure named cosine function cell-based (CFCB) lattice, in which cell rods are designed in the shape of cosine function curve. Several quasi-static compression tests are conducted to explore their compression behaviors, and their advantages are explored by comparing with traditional bodycentered cubic (BCC) lattice structure. Further, influences of several key parameters on mechanical performances are experimentally investigated for CFCB lattice structures. The experimental results indicate that CFCB lattice structures have distinct superiority in compressive stiffness and strength, and their energy absorption characteristics are more than twice as high as those of BCC lattice structure. Further, it is also found that their cell rod diameter and cosine function period length have larger influences on mechanical performances. Subsequently, association relationship between deformation modes and key parameters is numerically explored for CFCB lattice structures, and a distribution map is plotted for their deformation modes. The numerical results indicate that cell rod diameter is positively associated with their energy absorption characteristics, and negatively correlated with their densification strain. Besides, it is also found that the performance indicators exhibit a reducing trend firstly but increase with further raising period length on the whole. With increasing relative density, their energy absorption characteristics and plateau stress show a general upward trend, while a general downward trend is observed in their densification strain. Finally, based on collapse mechanisms of the typical unit cell, theoretical models are deduced to predict equivalent elastic modulus, Poisson's ratio and plateau stress for the proposed CFCB lattice structures.