Experimental and numerical study on the material characterisation of a structural silicone adhesive for point-fixed glass panels

Adhesive structural joints represent an effective solution to overcome the limitations of mechanical fixings in the increasing applications of glass in buildings. However, current design codes do not explicitly address this particular joint typology, making a combined numerical–experimental approach the only method for design assessment. Most structural adhesives used in point fixed glass (PFG) feature hyperelastic behaviour, thus, their performance depends largely on the stress state they are subjected to, making them inherently application dependent. For this reason, it is essential to characterise the behaviour of commercial structural adhesives for scenarios corresponding to typical structural applications and design loads. This study aims to characterize the behaviour of a new generation structural adhesive (Sikasil® SG-500), under relevant design scenarios, providing data to support the design of point-supported glass elements. To this end, a multi-step numerical-experimental approach was implemented, including two sets of models. The first set refers to bespoke models for bulk material characterization, including tension, compression and planar tension tests. The experimental results were used to implement a curve fitting procedure over a set of hyperelastic rheologic models in Abaqus software (Arruda-Boyce, Ogden N1 and N3, Polynomial N1 and reduced Polynomial N1, N2, N3 and N5). The second set corresponds to full scale models of façade configurations (isolated joints and façade panel with joints) subjected to typical façade load settings. The corresponding experimental results were compared with the numerical results for the selected hyperelastic models, in order to establish the best correspondence. The results indicate that the selection of suitable hyperelastic models based on statistical fitting provides reliable representation of the adhesive behaviour. In particular, the selected material model was able to reproduce the mechanical response of the adhesive with satisfactory accuracy within the strain range relevant for façade applications. These findings demonstrate that the proposed calibration strategy provides a consistent and reliable framework for the numerical modelling and design of bonded point-fixed glass façade systems.