Enhancement of a dual-directional graded honeycomb under dynamic crushing velocity

Abstract

Understanding the enhancement effects of graded design on the dynamic crushing behavior of honeycombs is crucial for engineering applications. This paper investigates the enhancing performance of a novel dual-directional graded honeycomb called modularized honeycomb (MH) under dynamic loading conditions. Finite element (FE) models of MH are developed and validated through drop weight impact tests. A theoretical model for predicting the dynamic plateau stress of MH is also derived. By analyzing both FE and theoretical results, it is concluded that for any average relative density and graded coefficient, the strength and specific plastic energy absorption of MH increase with crushing velocity, and MH consistently outperforms that of uniform honeycomb (UH). However, the enhancement coefficient, i.e., strength ratio between MH and UH, decreases as increasing crushing velocity. The underlying mechanism for this is uncovered based on the design principle and the theoretical model. Moreover, the enhancement coefficient and energy ratio exhibit insensitivity to average relative density under dynamic loadings. Overall, this paper reveals enhancement effects of modularized design on dynamic crushing behaviors of MH and provides insights into the differences between MH and UH, which could benefit development of excellent lightweight energy absorbers.