Computational modelling of the crushing of carbon fibre-reinforced polymer composites

Abstract

The use of lightweight carbon fibre-reinforced polymer (CFRP) composites in transportation vehicles has necessitated the need to guarantee that these new materials and their structures are able to deliver a sufficient level of crashworthiness to ensure passenger safety. Unlike their metallic counterparts, which absorb energy primarily through plastic deformation, CFRPs absorb energy through a complex interaction of damage mechanisms involving matrix (polymer) cracking, fibre/matrix debonding, fibre pull-out/kinking/fracture, delamination and inter/intralaminar friction. CFRP is primarily deployed as a laminate and can potentially deliver a higher specific energy absorption than metals. Translating this capability to a structural scale requires careful design and is dependent on geometry, fibre architecture, laminate stacking sequence and damage initiation strategies for optimal uniform crushing. Consequently, the design of crashworthy CFRP structures currently entails extensive physical testing which is expensive and time consuming. This paper reports on progress and challenges in the development of a finite-element computational capability for simulating the crushing of composites for crashworthiness assessments, with the aim of reducing the burden of physical testing. It addresses the ‘tyranny of scales’ in modelling structures constructed of CFRP composites. Intrinsic to this capability is the acquisition of reliable material data for the damage model, in particular interlaminar and intralaminar fracture toughness values. While quasi-static values can be obtained with a reasonable level of confidence, results achieved through dynamic testing are still the subject of debate and the relationship between fracture toughness and strain rate has yet to be satisfactorily resolved. This article is part of the theme issue ‘Nanocracks in nature and industry’.

LS-Dyna Impact Modelling on Carbon Fibre Reinforced Polymers (CFRP) Composite Aircraft Panel with Various Impactors

“…Figure 17 shows that the resultant force of the ogival impactor is 18.5 kN. The nonuniformities prove the stages of delamination and start with delamination onset [20]. After that, it enters into delamination growth, where significant damage is displayed.…”

Energy absorption capability of carbon/epoxy composite laminates: A novel numerical approach

“…Experimental methods, however, are time consuming and expensive. That is why researchers are getting more interested in FE Models [18][19][20][21][22] in recent years. Advances in commercial finite element analysis (FEA) software have enabled researchers to realistically simulate the performance of composite structures; however, computational cost is an issue to overcome.…”

Dynamic crushing of composite coupons: An experimental and numerical study

“…This issue has recently been discussed by another author. 21 Due to composite crushing being highly sensitive to external factors, numerical modelling of crashworthy FRP structures can be unreliable such that designs are often based on costly experiments. Therefore, to increase understanding, it is crucial to reduce the number of parameters or be able to quantify parameter influences.…”