Estimation of relevant shear properties of adhesive joints through analytical modeling of experimental torsion tests

The paper investigates the response of different adhesives joints under torsional loading. The stiffness and strength characteristics of the adhesives joints are estimated by fitting adaptable piecewise linear models with the experimental results of torsion tests. Efficient fitting techniques are adopted to estimate model parameters and effectively quantify relevant shear properties of the adhesive joints under test. The proposed experimental-analytical procedure represents a valid alternative to the conventional bending and shear tests reported in the literature: with respect to the bending tests, the torsion test yields more accurate results because it induces a pure shear stress rather than a complex bending-shear stress state; the torsion test is also easier to be performed with respect to the shear test, which requires testing fixtures that may locally affect the experimental results.