This work was aimed at investigating damage evolution within sandwich panels consisting of aluminum skins and Nomex™ honeycomb core, with three different values of the core densities, subjected to multiple impacts. Repeated impacts at low energy were conducted using an impact fatigue machine. Bending tests were conducted to determine the residual stiffness after impacts in order to analyze the evolution of a damage parameter D. A model was therefore proposed for describing the changes in this parameter as a function of impact cycles N. After repeated impacts, the D(N) curves are characterized by an S-shaped curve. A good agreement is observed between model and experimental results, the maximum standard deviation being less than 7% for different densities. Microscopic observations of the impacted specimens were conducted in order to evaluate the crater growth (associated with permanent indentation). The influence of the number of impacts on the dimensions of the impact zone has also been evaluated. For all the core densities, the permanent indentation gradually increases as a function of impact cycles.

这项工作旨在研究由铝皮和 Nomex™ 蜂窝芯组成的夹层板内的损坏演变，具有三种不同的芯密度值，受到多次冲击。使用冲击疲劳机进行低能量的重复冲击。进行弯曲试验以确定冲击后的残余刚度，以便分析损伤参数D的演变。因此提出了一个模型来描述该参数作为冲击循环N的函数的变化。反复冲击后，D(N)曲线以S形曲线为特征。在模型和实验结果之间观察到良好的一致性，不同密度的最大标准偏差小于 7%。对撞击样品进行显微观察以评估陨石坑的生长（与永久压痕相关）。还评估了撞击次数对撞击区尺寸的影响。对于所有的核心密度，永久压痕作为冲击循环的函数逐渐增加。