Evaluating Fracture Mechanical Parameters of a Thermally Loaded Structures

Dragi Stamenković, MSc (Eng)

 

The Finite Element Method (FEM) is used to determine thermally induced stresses in cracked structural components. These stresses can cause initiation of cracks and their propagation. Particularly, bimaterial interface cracks are an area of interest in evaluating Fracture Mechanical Parameters. The values of induced fields of stresses and displacements are related to the complex Stress Intensity Factors (SIFs). For determining Stress Intesity Factors (SIFs) in this paper, the J-integral approach is used. It is an energy based concept in which the J-integral, J, can be considered as a non-linear elastic equivalent of the energy release rate, G. This statement is valid only in the domain of Linear Elastic Fracture Mechanics (LEFM). The Stress Intesity Factors derived from the J-integral approach is less sensitive than that from the displacement extrapolation method. To illustrate the accuracy and efficency of the J-integral approach in fracture mechanics computations various numerical examples are included in this text.

Key words: fracture mechanics, thermal stress, multilayered structure, thermal load, thermal fatigue, crack, finite element method, J-integral.