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.

This study seeks to explore the effects of a protective bulkhead structure on the load and damage characteristics of a typical cabin under warhead internal blast, and guide protective bulkhead design for important ship cabins.

A typical double cabin structure model is designed in which the large cabin is used to simulate the explosion cabin, while the small cabin is used to simulate the important cabin. A comparative study is then carried out on the load and damage characteristics of the original bulkhead model and multi-layer liquid-containing protective bulkhead model under an internal explosion of thr shell warhead with 6.12 kg TNT, and an analysis is made of the load characteristics of fragments, shockwaves, structural crevasses, deformation damage characteristics.

The fragment flying angle produced by the front end of the warhead is basically the same, and there are fewer fragments at the front end than in the circumferential direction. The presence or absence of a protective bulkhead has little effect on the fragment load characteristics. The explosion shockwave has obvious corner convergence characteristics. The shockwave energy changes with the strength of the structure, and it is easier for the overall energy to pour into the weak parts of the structure. Under the combined damage of shockwave and fragments, the center of the conventional steel transverse bulkhead suffers a large break, while the multi-layer liquid-containing protective bulkhead only suffers large plastic deformation on the projectile-facing surface and perforation by a small number of fragments, with the structure of the projectile backing surface remaining complete. Multi-layer liquid-containing protective bulkheads can effectively prevent the transmission of explosive energy to the adjacent cabin, but they will aggravate the structural damage of the explosion cabin.

The "evacuating and blocking" protection design method has important practical application value for the protection of important ship cabins.