Flexural Enhancement in Beetle-Inspired Sandwich Plates with a Large Height-to-Thickness Ratio Core ^†

This study investigates the flexural mechanical properties of aluminum middle-trabecular beetle elytron plates (MBEP_N) with a significant height-to-thickness ratio core to understand how varying numbers of trabeculae (N) influence their bending resistance.

Introduction: Inspired by the natural world’s engineering marvels, this study delves into the biomimetics of materials and structures, focusing on the remarkable structural mimicry of beetle elytron plates. Beetles, among Earth’s most ancient organisms, have evolved lightweight yet robust elytra that conceal secrets of structural efficiency and durability. Mimicking the beetle elytron, we explore its analogous sandwich structure, akin to man-made aircraft wings, and its core’s unique configuration—a honeycomb network reinforced with strategically placed trabeculae. This bio-inspired approach not only pays homage to the beetle’s evolutionary refinement but also seeks to harness these natural designs for advanced engineering applications, embodying the essence of biomimetics in materials and structures.

Methods: This study employed a two-fold approach: quasi-static three-point bending tests on traditional honeycomb plates (MBEP₀) and bio-inspired MBEP₂ plates, followed by finite element analysis for MBEP variants (N = 2, 4, 6).

Results: MBEP₂ exhibited a notable 41.4% increase in flexural strength over traditional honeycomb plates. Contrary to expectations, higher N did not correspond to improved bending performance; instead, MBEP₂ outperformed others, including MBEP₆, with a distinct upward plateau on the load-displacement curve. Weak bending resistance was particularly noted near the upper plate of the first honeycomb wall across configurations, with deformation patterns varying with N. These findings suggest a complex relationship between trabeculae quantity and flexural performance, challenging simple linear assumptions.

Conclusions: This research uncovers previously unknown aspects of MBEP’s flexural performance, highlighting its potential for engineering applications. The variation in trabeculae numbers and distributions offers insights into optimizing the material’s mechanical properties for broader utilization in design and manufacturing.