Timoshenko Theory Solution for the Debond Characteristics of Sandwich Single-Cantilever-Beam Specimens

Abstract

This paper employs an elastic foundation approach and the Timoshenko beam theory and derives closed-form expressions for the energy release rate and mode partitioning of face/core debonds in the single-cantilever-beam sandwich composite configuration. In this regard, this paper extends our earlier work on this topic that was based on the Euler–Bernoulli theory. A single-cantilever-beam specimen of finite length is considered as having a debonded section, where the debonded top face and the substrate are not connected, and a bonded section, where an elastic foundation is used to connect the top face and the substrate. The interaction between the top face and the substrate in the bonded section is modeled using both normal and rotational (or shear) spring distributions. A [Formula: see text]-integral approach is used to derive a closed-form expression for the energy release rate. Subsequently, a mode partitioning approach based on the transverse and axial displacements at the beginning of the elastic foundation is implemented. This solution can be used for both isotropic and orthotropic faces and core. The results are compared with the corresponding ones from a finite element analysis and they are in very good agreement.