Failure analysis and verification of honeycomb sandwich structure based on interface element

Abstract

In the rampdown zone of the honeycomb sandwich structure, the load transfer path is complex, and the initial debonding damage easily occurs. The occurrence of the debonding will directly change the force transmission path and then promote the overall failure of the structure. The cohesive interface element is introduced to simulate the damage propagation of the adhesive layer under compression loads according to the quadratic nominal traction criterion and the energy-based B-K criterion. The failure mode of the Nomex honeycomb aluminum alloy panel sandwich structure and the load distribution of the inner and outer panels were experimented with by inplane compression load. Results show that the finite element calculation and experiment had a good consistency. The four corners of the rampdown zone were the maximum stress and the dangerous area. The adhesive layer at the sharp corner of the rampdown zone was damaged first, and the crack expanded along the bonding layer between the panel and the honeycomb. The adhesive layer debonding significantly decreased the local stiffness of the outer pane and prevented the outer plate's yielding under the compression load. In addition, the influences of the honeycomb performance, the wadding performance, and the radius of the curvature on the stress distribution of inner and outer panels were analyzed. It provides a optincal design of honeycomb sandwich structure.