Effect of crack parameters and stiffener layout on dynamic stress intensity factor of 3×3 grid stiffened panel at resonance

The fatigue crack generated during vibration would affect the fracture in structures. The 3×3 grid stiffened panel with the center crack was modeled using the finite element method. The modal recombination method was applied to rapidly compute the values of the Stress Intensity Factor (SIF) of crack tip in the panel at resonance. The influence of crack parameters (inclined angle and crack length) and the stiffener layout on SIF values was analyzed. The result shows that the maximum SIF values of the structures for Mode I, Mode II and Mode III showed different trends as the inclined angle of the crack increased (monotonically increase, no significant change, and increase first and then decrease). The maximum SIF values and crack mode were affected by the crack length. For the panels with the same crack parameters, different distribution of the stiffener results in different vibration shape, and thus causes different types of cracks. In particular, effect of the crack inclined angle on the SIF amplitude and crack mode can be ignored when the center region of the panel is square.