Design of structures with higher energy absorption (EA) capability and lower weight is always challenging in crashworthiness analyses. In this research, a three-step geometrical modification procedure is proposed to improve the crashworthiness of a bionic cylindrical sandwich structure filled by auxetic core layers under axial compression. This method includes a sequential procedure for simultaneous enhancement of the EA capability and reduction of the weight of the sandwich structure. The tubular structure is composed of thin-walled, wavy, auxetic core layers sandwiched by concentric thin-walled tubes. Finite element simulations involved modifying the geometry of the core layers and making the outer tube auxetic. Experimental test on a sample 3D-printed by the ABS-Like-Resin M58 indicated that the modified structure shows significant performance improvement, including up to 24% higher specific energy absorption (SEA), 16% higher mean crushing force (MCF), 20% higher crushing force efficiency (CFE), less than 5% lower initial peak force, and almost 6% weight reduction.

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