Adhesive connections in glass structures—part I: experiments and analytics on thin structural silicone

Abstract

The present paper describes different types of experimental test setups to determine material properties of thin structural silicone used as laminated connections in glass structures. Since it is of major interest to conduct homogeneous experiments with structural silicones, which belong to the family of rubber-like materials, the triaxiality will be introduced, which allows one to illustrate differences between homogeneous and inhomogeneous experiments. With the help of this scalar, it is possible to design experimental test setups, which ensure a homogeneous stress and strain distribution within the tested rubber-like material. Furthermore an engineering approach to determine the testing speed of arbitrary experiments dependent on one reference testing speed and experiment will be presented. This approach ensures equivalent strain energies between arbitrary and reference test specimens during testing, by which expensive strain rate controlled experiments can be relinquished, since rubber-like materials exhibit a strain rate dependency. Based on this, homogeneous experimental tests were conducted: uniaxial tension and compression, biaxial tension as well as shear-pancake tests. Furthermore, microindentation tests as inhomogeneous tests were performed. Afterwards the experimental results were processed in a manner that it is possible to identify hyperelastic material parameters via standard fitting routines as well as inverse methods, which will be presented in part II of this publication.