Increasing Necking Strain through Corrugation: Identifying Composite Systems That Can Benefit from Corrugated Geometry.

Mark Fraser,Hatem Zurob,Peidong Wu,Olivier Bouaziz

doi:10.3390/ma13225175

Abstract

Under some circumstances, composites with a corrugated reinforcement geometry show larger necking strains compared to traditional straight reinforced composites. In this work, finite element modeling studies were performed for linearly hardening materials, examining the effect of material parameters on the stress–strain response of both corrugation and straight-reinforced composites. These studies showed that improvements in necking strain depend on the ability of the corrugation to unbend and to provide a boost in work hardening at the right time. It was found that there is a range of matrix yield strengths and hardening rates for which a corrugated geometry will improve the necking strain and also a lower threshold of reinforcement yield strength below which no improvement in necking strain is possible. In addition, benefit maps and surfaces were generated that show which regions of property space benefit through corrugation and the corresponding improvement in necking strain that can be achieved.

Highlights

IntroductionMany forming processes are limited by the maximum uniform deformation or the necking strain.The necking strain of a material can be increased by introducing a wavy or corrugated reinforcement.There have been a number of studies that investigate the effect of a corrugated geometry on the behavior of isolated corrugations [1,2,3,4,5,6], sandwich panels with a corrugated core [7,8,9], and composites materials with corrugated reinforcements [3,4,10,11,12,13,14,15,16,17,18,19,20,21,22]
3a,matrix it is clear that if the matrix yieldthis strength is strain is very comparable to what the straight composite is able to achieve, and there is minimal too low, this necking strain is very comparable to what the straight composite is able to achieve, and there is minimal benefit to be found by using a corrugated geometry
Whether a composite system will improve its necking strain through corrugation is dependent first on whether the corrugation is capable of unbending and second on whether the boost in work hardening that comes from that unbending happens at the right time in the deformation process

Summary

Introduction

Many forming processes are limited by the maximum uniform deformation or the necking strain.The necking strain of a material can be increased by introducing a wavy or corrugated reinforcement.There have been a number of studies that investigate the effect of a corrugated geometry on the behavior of isolated corrugations [1,2,3,4,5,6], sandwich panels with a corrugated core [7,8,9], and composites materials with corrugated reinforcements [3,4,10,11,12,13,14,15,16,17,18,19,20,21,22]. The necking strain of a material can be increased by introducing a wavy or corrugated reinforcement. Examined sandwich panel structures with corrugated cores for the application of morphing wings in aviation. These studies have shown that when loaded in tension along the longitudinal direction, the corrugated structure shows a lower initial stiffness and lower strength level, followed by a hardening process as a result of the unbending of the corrugation. In some of the studies [3,4,6,13,21,23]

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