Structure design and performance regulation of metal 3D printing truss unit cells for impact buffering and energy absorption

LIU Feng; WANG Jiale; JIANG Liyun

doi:10.16579/j.issn.1001.9669.2026.08.009

Abstract：[Objective]Limited room exists for lightweight optimization and energy absorption improvement of traditional energy-absorbing buffer structures including thin-walled structures,honeycombs and foams,accompanied by insufficient structural design flexibility and working condition adaptability.Relying on metal 3D printing additive manufacturing technology,a spider-web-inspired three-dimensional truss unit cell for buffering and energy absorption was designed to enhance the specific strength,specific stiffness and specific energy absorption of structures,and optimize structural design flexibility and working condition adaptability.[Methods]Firstly,initial unit cell specimens were fabricated by metal 3D printing with AlSi10Mg powder,and quasi-static compression tests were conducted to obtain basic mechanical response data.Secondly,a finite element model of the initial unit cell was established,and simulation and test results were compared to verify model reliability.Then,the collapse mode and lightweight level of the unit cell were regulated through weak link design and redundant rod optimization.Finally,a variable-stiffness stacked periodic structure was constructed,and the regulation effect of the stacking strategy on overall energy absorption performance was analyzed.[Results]The results show that the initial unit cell presents a lateral offset mode during collapse,and the compression process is divided into four stages with a simulation error of peak load of 2.71％.The energy absorption performance of the unit cell increases nonlinearly with the rise of volume fraction.The weak link induces a torsional collapse mode via the"tree felling"effect,and the specific energy absorption is increased by 26.93％.Removing redundant rods reduces the unit cell mass by 15.42％and raises the specific energy absorption by 1.47％.The variable-stiffness stacking strategy can increase the specific energy absorption of the periodic structure by 38.43％,which can provide references for the design of buffering and energy-absorbing structures.