改进型体心立方结构准静态压缩下变形规律及吸能特性分析

Analysis of deformation law and energy absorption characteristics of an improved body centered cubic structure under quasi-static compression

  • 摘要:
    目的 为提高轻量化点阵结构的力学性能,基于多构型组合设计方法设计一种改进型体心立方(BCC)点阵结构(BCCZ)。
    方法 通过压缩试验,对比分析准静态压缩载荷下BCCZ与BCC点阵结构的力学性能和吸能特性;进一步采用数值仿真方法分析不同径长比下BCC与BCCZ点阵结构的力学性能及吸能特性,并采用数值仿真与试验相结合的方法对其力学性能进行研究,探究径长比对点阵结构压缩性能的影响。
    结果 结果显示,随着径长比的提高,2种点阵结构的弹性模量、抗压强度和比吸能均有所提高,且BCCZ点阵结构在这3个方面的性能均优于BCC点阵结构;BCCZ点阵结构的抗压强度大于BCC点阵结构,且提高率均大于100%,但BCCZ抗压强度的提高率整体上有下降趋势,而比吸能的提高效率则越发明显。
    结论 相关研究成果有助于船舶新型吸能防护结构设计。

     

    Abstract:
    Objectives In the context of the increasing demand in the shipbuilding industry for lightweight and high-energy-absorbing structures, this study aims to enhance the mechanical properties of lattice structures under lightweight conditions. A novel and improved body-centered cubic (BCC) lattice structure (BCCZ) is designed based on a multi-configurational design approach. This is crucial because traditional BCC lattice structures have limitations in load-bearing capacity and energy absorption capacity. The newly designed structure is expected to overcome these drawbacks, providing better solutions for shipbuilding and related fields.
    Methods To achieve this goal, a series of methods are adopted. Firstly, compression tests are conducted. BCC and BCCZ lattice structures with specific parameters (L1 = 15.0 mm, θ = 45.0°, L2 = 10.6 mm, D = 2.5 mm) are fabricated using selective laser melting (SLM). The mechanical properties and energy absorption characteristics of these two structures under quasi-static compression are compared and analyzed. Secondly, numerical simulations are conducted. By changing the diameter-to-length ratio (D/L) while keeping other parameters constant, 12 different structures are designed. The finite element method is used to study the effect of D/L on the mechanical properties and energy absorption characteristics of BCC and BCCZ lattice structures. This combined experimental and simulation approach ensures a comprehensive and in-depth understanding of the structural behavior.
    Results The results show significant differences between the two structures. In terms of deformation modes, the deformation processes of both structures can be divided into three stages: the initial linear elastic stage, the nonlinear damage stage, and the densification stage. However, the BCC structure is more stable during the nonlinear damage stage, while the introduction of vertical struts in the BCCZ structure changes its deformation mode from a bending-dominated structure to a coupled structure of vertical strut tension-dominated and inclined strut bending-dominated. With respect to mechanical properties, as the D/L ratio increases, the elastic modulus, compressive strength, and specific energy absorption of both structures increase. The BCCZ structure consistently exhibits better performance in these three aspects. Specifically, the compressive strength of the BCCZ structure is greater than that of the BCC structure, with an improvement rate of more than 100%, although the overall rate of increase in compressive strength shows a downward trend as D/L increases. In contrast, the improvement in specific energy absorption efficiency becomes more pronounced. In terms of energy absorption efficiency, the BCC structure is superior to the BCCZ structure, but this difference diminishes gradually as D/L increases.
    Conclusions In conclusion, this study provides valuable insights for the design of new energy-absorbing and protective structures in ships. The design of the BCCZ structure and the study of its performance under different D/L ratios offer a theoretical basis and practical reference for optimizing lattice structures in engineering applications. It also lays the groundwork for further research on lattice structures, such as exploring more complex multi-configurational designs and studying their behavior under dynamic loading conditions. The results can guide the selection of appropriate lattice structures in different engineering scenarios, promoting the development of lightweight and high-performance structures in the shipbuilding industry and other related fields.

     

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