Study On Deformation And Energy Absorption Of Multi-hierarchical Corrugated Core Sandwich Structures

Sandwich structure is widely used in engineering protection,construction,shipbuilding and other engineering fields due to its advantages such as high strength,good impact resistance,low production cost and simple production process.The hierarchical corrugated core sandwich structure not only realizes the requirement of lightweight structure,but also improves the energy absorption performance and crashworthiness of the structure.Based on the core layer of traditional corrugated core sandwich structure,three kinds of second order structure core layers are designed according to the design idea of hierarchical structure.The critical failure load formula of second order structure under quasi-static compression load is established.The deformation mode and energy absorption performance under quasi-static and impact loading are theoretically analyzed and numerically simulated.The effects of the number of layers and geometric parameters of the core layer on the deformation and energy absorption performance are studied.The main work is as follows:The theoretical critical failure load formula of the second order structure under the quasi-static compression loading is theoretically derived when considering the deformation of the horizontal small support of the structural core layer.The finite element software LS-DYNA is used to simulate the mechanical response of multi-hierarchical corrugate core sandwich structures with different geometric parameters under quasi-static and impact loading,and the result was compared with the first order structure.The theoretical prediction results are in good agreement with the numerical simulation results.The main factors affecting the structural deformation mode and energy absorption performance are geometric parameters of the structure,such as the thickness of the core layer,the thickness ratio of the small support and the outer slanting plate,the length ratio of the small support to the outer sloping plate and so on.The core layer with different geometric parameters has different deformation modes and energy absorption properties.There are three main deformation modes in the second order structure of the core layer,i.e.,the plastic deformation of the small support folding layer by layer,plastic deformation of integral oblique brace after deformation and compaction of small support,plastic deformation of integral oblique brace.Three deformation modes occur for single-layer of the second order structure,and two deformation modes occur for two-layers and three-layers of the second order structure.The energy absorption performance of the core of second order structure with different thickness and length ratio is better when the plastic deformation of small support folding layer by layer occurs in the core layer.The energy absorption performance of the core of second order structure with different thickness ratio is better when the core of the structure occur plastic deformation of integral oblique brace after deformation and compaction of small support.Under the quasi-static compressive loading,the specific energy absorption of the second order corrugated core sandwich structure is significantly higher than that of the first-order structure.With the increase of the thickness of the core layer,the specific energy absorption and load efficiency increases for two-layers and three-layers of the second order structure.With the increase of the thickness ratio of the small support and the outer slanting plate,the specific energy absorption and load efficiency of second order structure decreases.With the increase of the ratio of the length of the small support to the outer sloping plate,the specific energy absorption and load efficiency of the second order structure for single-layer increases,while the specific energy absorption decreases and loading efficiency no significant change for two-layers and three-layers of the second order structure.Therefore,the higher energy absorption performance of the hierarchical structure can be achieved by choosing the geometric parameters of the structure core layer in engineering applications.Under the impact loading,with the increase of the thickness of the core layer plate,the specific energy absorption and the crush load efficiency increases for two-layers and three-layers of the second order structure.With the increase of the thickness ratio of the small support and the outer slanting plate,the specific energy absorption increases and the crush load efficiency decreases for two-layers and three-layers of the second order structure.With the increase of the ratio of the length of the small support to the outer sloping plate,the specific energy absorption of the second order structure for single-layer increases,while the specific energy absorption of the second order structure for two-layers and three-layers slightly changes,and the crush force efficiency of the three structures increases.The research results can provide theoretical basis and technical reference for the design and engineering application of layered sandwich structure.