Effect of induced temperature field on development of curvilinear crack with bonds between the faces in end zones

Temperature changes near the end of a curvilinear cohesive crack and their influence on crack growth are investigated. The problem of local temperature changes consists in a delay or retardation of the cohesive crack growth. The bonds between the curvilinear crack faces in the end zones are modeled by application to the crack surface cohesive forces caused by the presence of bonds. The boundary value problem of equilibrium of the curvilinear crack with interfacial bonds in the end zones under action of external tensile loads, induced temperature field and tractions in the bonds preventing to its opening, is reduced to a system of singular integral equations with a Cauchy-type kernel. From the solution of this equation system, normal and tangential tractions in the bonds are found. Analysis of the limit equilibrium of the crack using the end zone model is performed on the basis of a criterion of bonds limiting stretching and includes: 1) establishment of tractions depending on opening of the crack faces; 2) evaluation of the stress state near the curvilinear crack with taking into account tensile loads, induced temperature field, tractions in the bonds; 3) determination of the critical external tensile loads

Effect of damages on crack development in coating on elastic foundation

A fracture mechanics problem for a coating linked to the basis made of another elastic material is considered. It is assumed that in the vicinity of technological defect (crack) in the process of loading in the coating, there will arise prefracture zones (damages) that are modeled as the areas of weakened interparticle bonds of the material. In the prefracture zones (interlayers of the overstressed material), the coating material is deformed beyond the limit of elasticity. It is considered that during loading in the cross section of the coating in the vicinity of the crack, there is an arbitrary number of rectilinear prefracture zones. The condition determining the limiting value of the external load at which the crack growth happens is obtained

INTERACTION OF PERIODIC SYSTEM HETEROGENEOUS INCLUSIONS AND COHESIVE CRACKS UNDER LONGITUDINAL SHEAR

The elastic medium weakened by a periodic system of circular holes filled with washers from homogeneous elastic material is considered. The surface of circular holes is covered by a cylindrical film. Medium (binder) is weakened by two periodic systems of rectilinear cracks with bonds between the faces in end zones. General representations describing the class of problems with periodic stress distribution out circular holes and cracks under longitudinal shear are constructed. The analysis of cracks limit equilibrium using the end zone model is performed based on nonlocal fracture criterion with force condition of the crack tip advance and deformation condition for determination of the crack end zone face advance