FRACTURE OF A PLATE UNDER TRANSIENT THERMAL STRESSES

Abstract

The cracking in a plate of finite thickness due to sudden thermal transient stresses is considered for an edge crack. The elastic strip is assumed to be insulated on one face and cooled suddenly on the face containing the edge crack. Even though the assumption of a step change in temperature on the boundary gives conservative results, it is not a realistic representation of the actual boundary condition. A ramp cooling function is assumed at the boundary, which is more realistic than the assumption of a step function. The inertia effects and the temperature dependence of the elastic constants are negligible. The thermal stresses for the uncracked problem are computed as a function of time. Then, these stresses are used as the crack surface tractions with opposite sign to formulate the mixed boundary value problem. This leads to a singular integral equation of Cauchy-type, which can be solved numerically. The numerical results for the stress intensity factor are computed as a function of the nondimensional time, the crack size, and the duration of cooling rate. Also, the temperature and the thermal stress distributions for the uncracked problem are included.