The fatigue crack propagation and analysis of crack behaviour

In this study, fatigue crack propagation is simulated by using one of the numerical analysis methods, finite element method. Linear fracture mechanics approach is not sufficient for ductile solids. However, elastic-plastic fracture mechanics approach require much more complicated mathematical models and most of the time the solution of them are too difficult. Therefore, the finite element method is applied for a case of fatigue crack propagation and stress analyses at the end of the crack are studied. ANSYS package program is used for the finite element solution. Fatigue crack propagation is applied to the CCT specimens made from AISI 1070 and 304 stainless steel. Stress and strain distributions are observed around the crack tip. At the beginning, stress level increases with increasing applied cycle number and then it reaches a steady state level. This behavior is attributed to the work hardining of the materials. Key Words: Fracture mechanics, fatigue, finite element, crack closure, finite element and ANSYS.