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

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.

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.

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.

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.