Stiff and strong, lightweight bi-material sandwich plate-lattices with enhanced energy absorption

Plate-based lattices are predicted to reach theoretical Hashin-Shtrikman and Suquet upper bounds on stiffness and strength. However, simultaneously attaining high energy absorption in these plate-lattices still remains elusive, which is critical for many structural applications such as shock wave absorber and protective devices. In this work, we present bi-material isotropic cubic +octet sandwich plate-lattices composed of carbon fiber-reinforced polymer (stiff) skins and elastomeric (soft) core. This bi-material configuration enhances their energy absorption capability while retaining stretching-dominated behavior. We investigate their mechanical properties through an analytical model and finite element simulations. Our results show that they achieve enhanced energy absorption approximately 2-2.8 times higher than their homogeneous counterparts while marginally compromising their stiffness and strength. When compared to previously reported materials, these materials achieve superior strength-energy absorption characteristics, making them an excellent candidate for stiff and strong, lightweight energy absorbing applications.

Automated summary

Plate-based lattices consisting of carbon fiber-reinforced polymer skins and elastomeric cores are proposed in this study to achieve enhanced energy absorption capability while maintaining stretching-dominated behavior. The results show that these bi-material structures can absorb energy approximately 2-2.8 times higher than their homogeneous counterparts, with marginal compromises in stiffness and strength. Compared to previously reported materials, these plate-lattices exhibit superior strength-energy absorption characteristics, making them promising candidates for lightweight energy absorbing applications requiring stiffness and strength.