Material parameter determination for the simulation of hyperelastic bonds in civil engineering considering a novel material model

In the field of structural glass, an increasing number of facade constructions is being manufactured using adhesives due to the possibility to achieve a maximum degree of transparency using circumferential bonds. The basis for the design of such load-bearing silicone bonds is currently the European Technical Approval Guideline 002 (ETAG 002) for Structural Sealant Glazing Kits. However, ETAG provides for a global nominal stress concept, which does not correctly represent the real three-dimensional stress state within the joint. The softening of the material typical of silicones (Mullins-effect) is also not covered. The guideline sets high safety coefficients, which do not consider the actual potential of the bond. In this article, a material model is presented which can realistically simulate the load-deformation behaviour of such bonds under consideration of multi-axial stresses and material softening. The focus here is on determining the necessary material parameters based on different, clearly determinable multi-axial basic tests as well as the validation of the model on small scale test specimens with complex loading analogous to Structural Sealant Glazing systems.