This paper aims to investigate the crashworthiness performance degradation of a damaged 5052 aluminum honeycomb panels under in-plane uniaxial quasi-static compression and the possibility of improving it using reinforcement tubes. The in-plane crushing behaviors and energy absorption capacities of the intact, damaged, and tube-reinforced damaged panels with different damage sizes in both X1 and X2 directions are numerically simulated by using the nonlinear FE method Abaqus/Explicit, and the crashworthiness performances are compared with each other. The validation of finite element model involves comparing the obtained simulation results with theoretical and experimental ones. Very good agreement between numerical, experimental, and theoretical results is achieved. The first maximum compressive load and the mean crushing load of the different honeycomb configurations are analyzed and compared through the load–strain curves. The energy absorption capacity of the damaged and the tube-reinforced damaged panels is calculated and then compared with their corresponding intact ones. The deformation modes are explained in detail. The obtained results show that the crashworthiness performance degradation is directly proportional to the damage size as well as the insertion of reinforcement tubes considerably improves in-plane crushing resistance of damaged honeycomb panels.

In this study, the effectiveness of an alternative approach to temporarily repair an open-hole damaged Nomex honeycomb sandwich structure is experimentally investigated. The repair process consists of a resin-infused carbon fabric wet layup patch adhesively bonded to the facesheets and Airex structural foam used as a core replacement plug. The specimens of intact, damaged and repaired Nomex honeycomb sandwich panels are subjected to the quasi-static three-point bending test. The panel's flexural performances are determined by analyzing the obtained load-displacement responses. The effectiveness of the proposed repair technique is evaluated by comparing the responses of the repaired panels with the ones obtained from the intact and damaged panel specimens. The comparison is effectuated in terms of mean values of flexural elastic modulus, peak force, energy absorption, and specific energy absorption. In addition, the observed failure modes of the different panel configurations are pointed out and discussed.

In the present study, a numerical investigation of three-point bending test of the open-hole damaged sandwich structures with Nomex TM honeycomb core and aluminium alloy skins is carried out. In order to evaluate the degradation of the mechanical properties of these damaged structures, a finite element model is realized and tested using Abaqus/Explicit. To validate the accuracy of the numerical model, the obtained numerical results of the intact panels are calibrated with the experimental results. The load-displacement curves of the damaged structures showed a significant decrease of the peak force and the flexural elastic modulus compared to the intact ones. The study indicated that the degradation level of these mechanical parameters is in a direct relationship with the damage size. In addition, the energy absorption of the damaged panels is calculated and compared to the intact one.

As lightweight structures, composite sandwich panels are distinguished by their significant flexural performances, which make them suitable for lightweight design applications, especially in the aerospace industry. These structures are very prone to different damages, which affects the structure’s performance. In this study, the numerical three-point bending test is carried out to evaluate the flexural performance of the damaged and repaired panel by comparing it with the intact panel values. The response surface methodology (RSM) is then adopted to analyze the core plug replacement properties’ effect on the flexural performances of the repaired honeycomb sandwich panel. Adequate models between the core plug replacement design parameters and the repaired panel flexural responses are built and discussed. In addition, aiming to determine the optimized core plug replacement parameters of the proposed repaired panel flexural performances, an optimization technique is implemented.