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Abstract: The work presents a theoretical study (an asymptotic analytical and a semi-analytical) of the interaction of two parallel cracks under Mode II loading corresponding to the loading in the Compact Shear Specimen. Approximate analytical formulas for the stress intensity factors at the crack tips are derived. A numerical calculation for the corresponding integral equations is presented. The influence of geometry of the problem, i.e. the crack inclination angle to the remote shear loading and the distance between the cracks, on the SIFs and on the angles of the initial propagation direction of the cracks is investigated. [Copyright &y& Elsevier]

Abstract: In the fabrication process of ceramic composite materials or in service interface cracks could appear in one of the constituents. This work reports the stress intensity factors solution of a kinked crack whose corner is on the interface of two bonded dissimilar ceramic materials subjected to tension parallel to the interface and to tension normal to the interface. The finite element method was used to calculate the stress intensity factors at the tips of the crack. The effects of the material properties of the ceramic composite constituents, the kinked crack length, the interface crack length, and the kinked angle were investigated. A convergence study was carried out in order to find the proper distance r for collecting the displacement data for the crack flank displacement method. Results for the modulus of the complex stress intensity factors for the bi-material combinations with the homogeneous case, based on Suo and Hutchinson approach show consistent agreement for a range of interface crack lengths, kinked crack lengths and kinked angles. [Copyright &y& Elsevier]

Highlights: [•] Digital Image Correlation was used to measure R-curve of clay brick blocks. [•] DIC allows to collect data from crack propagation up to the total rupture of samples. [•] An average K IC of clay brick blocks equal to 0.36MPam1/2 was estimated. [•] A quite accurate R-curve of clay brick blocks was traced. [ABSTRACT FROM AUTHOR]

Abstract: Analysis and fracture interpretation (using the strain energy density criterion) of Compact Shear specimen for Mode II fracture testing of materials is presented in the paper. Two approaches are used. One is based on singular integral equations for the problem of the interaction of two parallel cracks under Mode II loading corresponding to the loading in the Compact Shear specimen (CS specimen). Approximate analytical formulas for the stress intensity factors at the crack tips are derived. A numerical calculation using Gauss-quadrature formulae for the corresponding integral equations is presented. The influence of geometry of the problem on the stress intensity factors and on the angles of the initial propagation direction of the cracks is investigated. The other approach is Finite Element Method implemented in FRANC2D/L code. Numerical analysis was done for plain strain conditions. Different geometries of the specimen are considered for two models of the CS specimen and compared with results available in the literature. Analytical and FEM calculations are also compared and discussed. [Copyright &y& Elsevier]