Damage mechanics-finite element method for vibration fatigue life prediction of engineering structures under resonant loading

For predicting vibration fatigue life of engineering structures under resonant loading, damage mechanics-finite element method was constructed. According to the law of thermodynamics, a new damage evolution equation with fractional form was constructed. The fatigue life prediction method for smooth specimen under the repeated loading with constant strain amplitude was constructed. By the theory of conservative integral, the function was derived to express the relation between the stress and fatigue life under the repeated loading with constant amplitude. The material parameters could be obtained by the results of fatigue test of standard specimens. Based on the platform of ANSYS that was the further development of APDL language in ANSYS, damage mechanics-finite element method for vibration fatigue crack initiation life prediction under resonant was used. The vibration fatigue crack initiation life for LC9CgS1 aluminum alloy beam was predicted. This research provides the possibility for predicting the vibration fatigue lives of structure members through the methodology of damage mechanics.