Efficient crack analysis of dynamically loaded structures using a modal superposition of stress intensity factors

The fatigue analysis of large engineering structures using Fracture Mechanics is usually conditioned by the computationally expensive numerical models needed, leading to difficult use in dynamic analyses. This paper presents a novel methodology developed with the aim to overcome the above mentioned limitation. A new concept, of modal stress intensity factor, arises, allowing a strong reduction of the calculations needed, yet keeping the accuracy. This methodology was tested using a simple example. Results were in excellent agreement with those obtained with common procedures and with widely accepted handbook expressions. The methodology proved to be compatible, also, with the utilization of submodeling techniques.