Papers by Keyword: Bi-Material Notch

Abstract: In order to evaluate the shear bond strength of a steel-concrete joint using an epoxy adhesive interlayer, push-out tests were carried out. The test samples consisted of two sandblasted steel plates and a self-compacting concrete sample, with the epoxy layer applied on the steel plates and gritted with granulates. During testing, an external force was applied to the concrete core and continuously recorded. To investigate the failure mechanism in detail, a fracture mechanics approach is required. In this paper theoretical-numerical assessment of the push-out test is performed. Regarding the finite element calculations, the locations suitable for failure initiation match bi-material (steel-concrete) notches. The most dangerous locations are evaluated from a generalized linear elastic fracture mechanics point of view. The critical load corresponding to the conditions of failure initiation is estimated and compared with the experimental results.

Abstract: A bi-material notch composed of two orthotropic parts is considered. The stresses and displacements are expressed using the Stroh-Eshelby-Lekhnitskii formalism for plane elasticity. The potential direction of crack initiation is determined from the maximum mean value of the tangential stress or the local minimum of the mean value of the generalized strain energy density factor in both materials [1, 2]. The matched asymptotic procedure is introduced to derive the change of potential energy for the debonding crack and the crack initiated in the determined direction [3].

Abstract: The bi-material notch composed of two orthotropic parts is considered. The radial and tangential stresses and strain energy density is expressed using the Stroh-Eshelby-Lekhnitskii formalism for the plane elasticity. The potential direction of the crack initiation is determined from the maximum mean value of the tangential stresses and local minimum of the mean value of the generalized strain energy density factor in both materials. Matched asymptotic procedure is used to derive the change of potential energy for the debonding crack and the crack initiated in the determined direction.

Abstract: The study of bi-material notches is becoming a topical problem as they can model geometrical or material discontinuities efficiently. Assessing the conditions for crack initiation in bimaterial notches makes it necessary to calculate the generalized stress intensity factors H. In contrast to the determination of the K factor for a crack in an isotropic homogeneous medium, for the ascertainment of a generalized stress intensity factor (GSIF) there is no procedure incorporated in the calculation systems. The calculation of these fracture mechanics parameters is not trivial and requires certain experience. Nevertheless, the accuracy of the H-factor calculation directly influences the reliability of the assessment of the singular stress concentrators. Direct methods of the estimation of H factors usually require choosing the length parameter entering into the calculation. Two types of direct methods of calculating the GSIFs are presented, tested and mutually compared. Recommendations for reliable estimation of H factors are suggested.