A numerical and experimental study of the material properties determining the crushing behaviour of pultruded GFRP profiles under lateral compression

Abstract

The present work aims at determining the critical material properties that can be used to tailor the crush behaviour of pultruded GFRP (Glass Fibre Reinforced Polymer) box-beams, as can be found in, for example, roadside furniture such as guard-rails. For this purpose, the mechanical behaviour and energy absorption mechanisms of the constituent pultruded box-beam sections subjected to lateral compressive loading, the dominating load case in composite structures when used as roadside furniture, have been studied. The analysed pultruded profiles consist of E-glass fibre reinforcements with two different lay-up configurations in a polyester matrix. The lateral crushing of profile sections is experimentally evaluated and further numerically studied using commercially available tools, applying readily available models incorporated in the software, in analogy to common practice in designing structures, to identify design and material parameters for improving the fracture behaviour of pultruded GFRP profiles. From the analyses, it is shown that the junctions between flanges and webs are the weakest points of box-beam sections: here, high shear stress concentrations in combination with occurring matrix failure lead to further damage such as delamination and tearing. This behaviour is well-described using the Hashin damage model within ABAQUS. Predicted failure behaviour corresponds with observed experimental results, whereas the material stiffness is underestimated. It is shown that the out-of-plane properties (transverse tensile and shear strength) are the dominant parameters affecting the overall performance.