Cohesive zone modeling of coupled buckling - Debond growth in metallic honeycomb sandwich structure

Buckling-induced skin-core debond growth in honeycomb sandwich cantilever beam is demonstrated using a cohesive zone model. The input parameters for the analysis are interfacial bond strength, mode I and mode II interfacial fracture toughness values, obtained from flatwise tension tests, drum-peel tests and three-point end notch flexure tests, respectively. Debonded honeycomb specimens are tested and the acoustic emission technique was used to observe the initiation of the debond growth. The load-displacement response from the cohesive zone model model shows a good agreement with the experimental results. The conventional analysis without cohesive zone model overestimates failure load by 56%. Cohesive zone model is able to predict the coupled debond growth and buckling failure in honeycomb sandwich structures.