Experimental and numerical investigation on damage behavior of honeycomb sandwich panel subjected to low-velocity impact

This paper presents the low-velocity impact behavior of sandwich panel with carbon fiber reinforced plastic (CFRP) composite facesheet and Nomex honeycomb core through experimental and numerical methods. Experiments were carried out on two thickness of honeycomb core at various impact energy levels. The dynamic response including contact force history and energy absorption as well as contact duration was recorded. The damage modes were obtained through non-destruction inspection (NDI) C-scan and microscopic observation. A refined three-dimensional finite element model combined with continuum damage mechanics (CDM) was developed with composite plies and detailed honeycomb core. Physically-based Puck's composite failure criteria and energy based progressive damage model were used to capture the intralaminar damage initiation and evolution, respectively. The interlaminar damage of facesheet and debonding of facesheet/core interface were predicted using cohesive element. The hexagonal honeycomb cells were characterized in FE model with an elasto-plastic constitutive model and damage criterion in detail during impact. The simulation results show good agreements with experiments and the model can be used to predict the low-velocity impact response and impact damage effectively. More detailed responses, such as internal damage details, damage modes and evolution, are observed and discussed with the numerical model proposed.