Energy absorption and quasi-static compression performance of carbon fiber composite double-layer pyramid sandwich structures

In recent years, sandwich structures have gained considerable attention in the fields of structural protection and energy absorption due to their lightweight and high-strength characteristics, holding great research significance. Traditional pyramid sandwich structures exhibit poor mechanical performance and energy absorption capability under axial loads. Therefore, this paper proposes three new three-dimensional double-layer pyramid sandwich structures, namely the type I double-layer symmetrical pyramid (TDSP I) structure, the type II double-layer symmetrical pyramid (TDSP II) structure, and the Type III double-layer symmetrical pyramid (TDSP III) structure. TDSP I introduces a double-layer pyramid unit based on the conventional single-layer pyramid sandwich structure. TDSP II further incorporates vertical struts on the basis of TDSP I, while TDSP III integrates reinforcing ribs in addition to the vertical struts. In terms of materials, carbon fiber is employed for the upper and lower face sheets, whereas 316L stainless steel is used for the core. The combination of these two materials enables the structure to maintain its lightweight characteristics while achieving enhanced structural stability and improved energy absorption performance; The study analyzes the force-displacement curves of these structures and provides a comprehensive comparison based on their deformation mechanisms and energy absorption capabilities. The research found that the specific energy absorption (SEA) of the TDSP III structure is 2.16 times that of the TDSP I structure and 1.58 times that of the TDSP II structure. Additionally, the paper explores the impact of different structural parameters on the energy absorption performance of the TDSP III structure. The results show that parameters such as the inclination angle of the support legs, leg thickness, and the lay-up angle of the carbon fiber panels significantly affect the overall energy absorption performance, allowing for directional regulation of energy absorption characteristics. In conclusion, the proposed double-layer symmetrical pyramid sandwich structure demonstrates promising engineering application prospects and research potential in structural protection and lightweight, high-efficiency energy absorption.