Torsion problems for bonded bars by an elastic adhesive layer

Torsion problems for a stepped-bar composed of two semi-infinite bars bonded to each other by an elastic adhesive layer are investigated. When the behavior of the adhesive layer is handled in elasticity, a stress singularity occurs at the corner of the bar. Therefore, the stress analysis takes this stress singularity into account with the aid of a series expansion technique, and the problems are reduced to an infinite set of systems of linear equations. Moreover, the stress fields in the neighborhood of the corner are shown by singular terms with only one parameter, which is similar to the stress intensity factor. The stress distribution and the values of this parameter are shown for various values of the mechanical properties of the bars and the adhesive layer. In addition, the results are compared with the ones for problems in which the behavior of the adhesive layer is approximated by that of shear springs.