双材料拼图式多孔结构准静态压缩力学行为

Quasi-Static Compression Behavior of Dual-Material Jigsaw-Like Porous Structures

  • 摘要: 针对传统一体式多孔结构性能调控灵活性的问题,提出了一种拼图式多孔结构。通过3D打印技术构建内凹连接与圆形连接两种连接方式的拼图式多孔结构,结合聚乳酸(PLA)和碳纤维(CF)两种材料,通过开展准静态压缩实验并结合有限元仿真验证,研究材料类型、连接方式、材料排列模式及阵列规模(3×3、4×4和6×6)对结构承载能力、变形模式和吸能特性的影响。实验表明:CF材料能够显著提高结构峰值承载能力与吸能特性,但更容易在边角及连接节点处发生脆性断裂;PLA材料则表现出更稳定的塑性变形特征。内凹连接结构具有更高的初始刚度和峰值承载能力,而圆形连接结构能够有效缓解局部应力集中并保持较稳定的平台承载能力。双材料排列方式能够改变结构的失效路径,其中单元交替排列结构表现出较优的承载能力,行交替结构表现出优秀的吸能特性。例如3×3-UA-N1的峰值力达到2.629 kN,较同组其它结构提高15.56%~34.47%。随着阵列规模增大,结构变形由整体协同压缩逐渐向局部剪切失稳演化,尺寸效应更加显著,峰值力由3×3结构的1.548kN-2.857 kN提高至6×6结构的1.801-3.729 kN。研究表明,双材料拼图式多孔结构为模块化轻量化可定制防护结构设计及性能调控提供了设计参考。

     

    Abstract: To improve the flexibility of performance regulation in traditional monolithic porous structures, a jigsaw-like porous structure was proposed. Jigsaw-like porous structures with two connection modes, namely concave connections and circular connections, were fabricated by 3D printing. Polylactic acid (PLA) and carbon fiber (CF) were used as constituent materials. Quasi-static compression experiments were carried out and combined with finite element simulation validation to investigate the effects of material type, connection mode, material arrangement pattern, and array size (3×3, 4×4, and 6×6) on the load-bearing capacity, deformation behavior, and energy absorption characteristics of the structures. The experimental results show that CF can significantly improve the peak load-bearing capacity and energy absorption performance of the structures, but it is more prone to brittle fracture at the corners and connection nodes. In contrast, PLA exhibits more stable plastic deformation characteristics. The concave connection structures have higher initial stiffness and peak load-bearing capacity, whereas the circular connection structures can effectively alleviate local stress concentration and maintain relatively stable plateau load-bearing capacity. The dual-material arrangement can change the failure path of the structures. Among the different arrangement patterns, the unit alternating arrangement exhibits superior load-bearing performance, while the row alternating arrangement demonstrates excellent energy absorption characteristics. for example, the peak force of 3×3-UA-N1 reaches 2.629 kN, which is 15.56%–34.47% higher than those of the other structures in the same group. As the array size increases, the deformation of the structures gradually evolves from overall cooperative compression to local shear instability, and the size effect becomes more significant. The peak force increases from 1.548–2.857 kN for the 3×3 structures to 1.801–3.729 kN for the 6×6 structures. The results indicate that the dual-material jigsaw-like porous structures provide a design reference for modular, lightweight, customizable protective structures and performance regulation.

     

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