Structural adhesive SikaForce 7710 L100 - Experimental characterization

Structural adhesives are an essential element in the majority of the structural glass constructions. Present design guidance for structural glass is not yet completed established, and does not cover complex systems, often required for large structures or elaborated details. For these cases, the design must be established from numerical modelling calibrated with results from full scale testing. The preparation of effective numerical models requires the accurate knowledge of the geometry and mechanical properties of all the materials involved. This is particularly critic in structures encompassing flexile materials, namely adhesives, in the sense it affects global deformability, the distribution of internal forces, and ultimately the resistance. Adhesive materials are rubbery polymers with complex behaviour affected by a number of factors like load duration and environmental factors, and feature mainly hyperelastic behaviour. For these reasons, the full characterization of the structural behaviour of adhesives is complex. In terms of experimental assessment, a significative number of tests is needed, opposite to what happens with standard non-flexible materials. The aim of the present work is to present the experimental characterization of the structural adhesive SikaForce 7710 L100, and the subsequent establishment of calibration parameters needed for fitting to hyperelastic models in the FE code Abaqus. The experimental tests were performed at the Civil Engineering and Mechanical Engineering departments of the University of Coimbra, Portugal (2017). The tests included uniaxial tension, plane tension and plane shear (Fig. 1 to 3). An optical data aquision system was used to ensure the necessary accuracy (Fig 4).