Objectives In order to effectively evaluate the safety and integrity of buoyancy material integrated structures in underwater vehicle in the service state in deep water, the generation and propagation of debonding damage at the interface between steel and buoyancy materials were studied by experimental and simulation methods.

Methods Firstly, the mechanical parameters of the material interface are measured based on standard tests and numerical calibration, and a cohesive contact model for interface failure simulation is constructed. Then, based on finite element simulation, the region of high stress gradient and the location where damage is easy to occur are estimated based on global stress / deformation analysis, and the expansion path and mode of debonding are determined by means of submodel simulation.

Results Interface debonding is prone to occur in the top area of the circumferential partition frame inside the integrated structure, with debonding mainly occurring in I-type and extending along the circumferential direction and towards the outer surface of the structure.

Conclusions The interface failure position and evolution can be understood, providing a basis for the simulation of interface failure under complex working conditions and for the optimization of interface performance in the future.