Numerical Fatigue-Life Prediction of Hyperelastic Polyurethane Adhesive Joints for Different Mean Stresses Using a Fracture-Mechanics Approach

Owing to the advantages of polyurethane adhesives, they are increasingly used in lightweight structures, where they are subjected to cyclic loading. Despite the growing use of hyperelastic adhesives, to date they have mainly been investigated under simple cyclic conditions, even though in practice they are subjected to more complex loadings such as variable mean stresses. Because of insufficient knowledge, there is no validated method for fatigue-life-oriented design of adhesive joints under this type of loading. In the research project presented here, continuum-mechanics and fracture-mechanics tests are therefore carried out to characterise a hyperelastic adhesive. On this basis, the fracture-mechanics calculation method is validated using uniaxial cyclic tests with variable mean stresses in order to enable fatigue- life prediction under more complex loading scenarios.