An investigation of the stress singularity near the free edge of scarf joints

The singular stress field which develops at the interface corner of a scarf joint between two bonded elastic solids is investigated. Depending upon the scarf angle and the material elastic properties, the singular stresses at a radial distance r from an interface corner may be expressed in the form Hrλ−1, where λ − 1 is the order of the stress singularity and H is the intensity of the singularity. The intensity H of the singularity at the interface corner of scarf joints subjected to a remote uniform tension is evaluated for various material combinations and a range of scarf angles using a combination of the finite element method and a path independent contour integral. Two types of scarf joints are considered: (i) a scarf joint between two long bi-material strips and (ii) a scarf joint consisting of a thin elastic layer sandwiched between two substrates. The role of the intensity H , which determines the amplitude of the stress field within the singularity zone, is examined and the implications of the results for the initiation of joint failure are discussed.  Elsevier, Paris stress singularity / bonded joints / contour integral / failure initiation / finite element method