Characterisation and FE simulation of polyurethane elastic bonded joints under multiaxial loading conditions

Abstract Structural bonding with so-called elastic adhesives like polyurethane or silicone adhesives is increasingly being used for various applications in the automotive, transportation, and building industry. Elastic adhesives can bond dissimilar materials such as steel, glass or plastics together. Elastic adhesives can withstand large levels of deformation at failure and are therefore very useful to compensate movements coming from crash, fatigue or thermal loadings which can weaken the surrounding structure. In order to design elastic adhesives using numerical methods such as Finite Element analysis, it is crucial to be able to predict the mechanical behavior of the adhesive joint accurately. This implies to characterize the behavior of elastic joints submitted to real situations such as multi-axial loadings and large deformations. This paper presents the development of experimental methods based on Digital Image Correlation techniques to measure the local multi-axial deformation behavior of a polyurethane adhesive. Experimental results are then used to identify constitutive parameters of hyperelastic materials models that make it possible to predict the non-linear elastic behavior of the adhesive up to large levels of deformations under multi-axial loading conditions and prior to failure using FE simulation. The methodology is validated by testing and simulating specimens which geometry are representative of bonded joints under service conditions.