Simplified analytical method for predicting the large deformation of stiffened plates with initial cracks under repeated impacts

The impact resistance capacity of structures can be affected by the formation of cracks. To address the issue of repeated impacts on structures with initial cracks, a relationship was established between cracks and the energy dissipation of stiffened plates based on rigid–plastic theory. A simplified analytical method was proposed to predict the large plastic deformation of stiffened plates with initial cracks. To verify the accuracy of the analytical method, repeated impact experiments and numerical simulations were conducted. The influences of crack length and position on the dynamic responses of stiffened plates were explored. The experimental, numerical, and analytical results were in good agreement. The research results showed that the permanent deformations of stiffened plates increases approximately linearly with increasing crack length on the outer plate. However, the influence of stiffener cracks on the permanent deformation of stiffened plates depends on whether the stiffener fractures. The influence of cracks on the load-carrying capacity of the structure is more pronounced when the crack is located in the stiffener. •A simplified analytical method was proposed for predicting the plastic deformation of stiffened plates with cracks.•Repeated impact experiments were conducted to assess the dynamic responses of stiffened plates with initial cracks.•The analytical results were in good agreement with the experimental and numerical results.•The influences of crack length and position on the dynamic responses of stiffened plates with cracks were investigated.