Resumen en Inglés:

Abstract The purpose of this paper is to present the results of stress-strain analyses of cantilever sheet pile walls in which structural elements consist of spaced concrete piles considering the plane strain (2D) and triple stress (3D) states for the soil mass. The results show that there are significant differences in the stress and displacement distribution obtained in the 2D and 3D analyses of the retaining walls. It was observed that the 2D analyses did not allow for a satisfactory evaluation of the influence of the distance among the structural elements of the retaining wall on the evaluated stresses, while the 3D analyses indicated that there is an increase in the confining stresses as the distance among the piles decreased, responding to the formation of the arch-effect in cohesive soils. It was also observed that the horizontal displacements obtained in the 2D analyses were greater than those in the 3D simulations, suggesting a conservative tendency in the two-dimensional approaches for the analyzed structure. In general, it was observed that 3D analyses were more suitable for evaluating the stress-strain behavior of cantilever sheet pile walls consisting of spaced concrete piles, allowing a more realistic assessment of their performance in situations where the structural elements are spaced apart.

Resumen en Inglés:

Abstract During penetration into large-sized multimedium materials, shaped charge jets are affected by jet fracture and interface effect, leading to reductions in their penetration performance. A theoretical model and calculation method for the penetration of shaped charge jets into asphalt/soil/concrete composite targets were established and experimentally verified to explore the law of the jet-induced damage of large-sized multimedium materials. The influence of the shaped waves generated during the penetration of shaped charge jets, jet fracture, and the interface effect at the interface between different media on the penetration performance of shaped charge jets were taken into account. The theoretical calculation results are in good agreement with the test results. In addition, through dimensional analysis and theoretical calculation, the curve chart of the relationship between total penetration depth and asphalt/soil part thickness is obtained. This chart can quickly reflect the law of the penetration of shaped charges into media with differing thicknesses.

Resumen en Inglés:

Abstract In this study, a multi-objective optimization methodology is used to assess the crashworthiness of an aluminum foam-filled battery box designed for passenger cars. Unlike most research focusing on axial crushing, this work investigates the less-explored side pole impact scenario in electric vehicle battery boxes. Finite element simulations are conducted to reduce peak crushing force (PCF) and increase specific energy absorption (SEA) compared to the initial design. Key design variables include aluminum foam densities, wall thickness, and cross-sectional dimensions of battery box components. Four surrogate models are evaluated to approximate the simulation results, and the Non-Dominated Sorting Genetic Algorithm (NSGA-II) is employed to achieve optimal outcomes. The results show that the optimized design significantly improves crashworthiness, achieving a 50.71% increase in SEA and an 11.56% reduction in PCF. Foam density plays a crucial role in controlling deformation behavior under impact conditions. These findings offer a new approach to designing battery boxes with enhanced crashworthiness for electric vehicles.

Resumen en Inglés:

Abstract To enhance the mechanical properties while keeping controlled auxetic performance, a novel circular reinforced re-entrant arched honeycomb (CRRAH) structure is developed. CRRAH specimens were additively manufactured, and quasi-static compression tests were conducted to evaluate their performance. Results demonstrate that superior mechanical performance is presented by comparing to the conventional re-entrant arched honeycomb structures, including a remarkable 208% increase in specific energy absorption (SEA). The finite element model, validated against experimental results, was further used to explore the deformation mechanism and auxetic performance of CRRAH structures with varying thickness ratios (γ). Results indicated that integrating circular rib within the re-entrant cells effectively restricts the continuous rotational stretching of inclined ligaments, resulting in a two-stage collapse process. This significantly enhances the deformation stability and energy absorption capacity. Moreover, adjusting the thickness ratio γ shifts the deformation mode from localized shear band formation to uniform global deformation with slight lateral expansion. Moreover, the dependence of deformation and the indentation resistance performance on thickness ratio were explored and the underlying mechanism was revealed. These findings provide valuable insights into the design of advanced re-entrant honeycomb structures, combining improved crashworthiness with controlled auxetic effects.