In view of the failure of type-I steel sandwich plate interfaces, this paper analyzes their interface fatigue debonding characteristics.

Based on the cohesive force model and considering the time history, damage evolution equations and convergence criteria of 3D structural nodes with multiple degrees of freedom, an interface fatigue debonding simulation program suitable for 3D complex structures is developed. The accuracy of the developed program is verified through a comparison with the experimental results of welding joint debonding, and the interface fatigue debonding behavior of type-I steel sandwich plates is simulated numerically.

The results show that the maximum simulation error between the 3D interface fatigue debonding test and debonding experimentis only 14.05%. When an type-I sandwich plate is subjected to out-of-plane load, the debonding failure at the interface mainly manifests as surface crack propagation in the direction of the extended weld. When the crack propagation reaches about 70% of the length of the plate, the crack begins to penetrate through the web to form a penetrating crack.

The interface fatigue debonding program developed herein can effectively evaluate the interface fatigue debonding life of type-I steel sandwich plates, giving it certain guiding significance for practical engineering applications.