Stability and Failure of the Edge-Closed Honeycomb Sandwich Panels with Face/Core Debonding

Abstract

This study investigated the mechanical performance of the edge-closed honeycomb sandwich structure with face/core debonding under compressive load by experimental and numerical methods. Uniaxial compression tests of asymmetric sandwich structures with various debonding sizes between the carbon/epoxy face sheets and the honeycomb core were conducted. The experimental results showed that the failure of debonding specimens was mainly caused by the local buckling of face sheets at the debonding area. The failure zone of sandwich structures gradually translated from the edge-closed beveled area to the debonding area with the increase of debonding sizes correspondingly, Meanwhile, the stability and the load carrying capacity of sandwich structures were in a downtrend. Compared with the nondestructive specimens, the residual strength of two kinds of defective specimens decreased by 9.9% and 22.1%, respectively. The simulation of the developed numerical model based on the linear buckling theory and the continuum damage mechanics agreed well with the experimental data. The study has guide to assess on the damage tolerance of edge-closed honeycomb sandwich panels with face/core debonding.

三维蜂窝碳的研究进展综述：性能和应用

“…(3)加载速率 蜂窝碳的力学性能还受到加载速率的影响。 在较 高的加载速率下， 蜂窝碳的强度和刚度都会明显提高。 CHC 的单轴拉伸力学性能与其特殊的结构密切 相关。在单轴拉伸试验中，通过对蜂窝碳样品施加沿 着一定方向的拉伸载荷，可以得到其应力-应变关系 和力学性能指标。在单轴拉伸试验中 [88] [51] 对垂直于铰链方向的蜂窝 碳结构进行了单轴压缩的分子动力学模拟。起初，研 究人员只是在堆叠的吸管构成的宏观蜂窝结构中观 察到了局部压缩现象 [89] ， 于是便引申到微观蜂窝碳在 压缩时是否也会出现类似的局部变形现象的研究中 来。模拟表明，除了最小的晶格外，所有蜂窝无论晶 格大小或模拟盒子的大小都发生了局部压缩。 以下是 整个压缩过程：首先是晶格的均匀压缩，每个晶胞会 发生弯曲，直到达到了临界应变水平，其中一个晶格 的壁接触到周围的壁并黏附在一起， 形成一个成核点， 随后一列内部的晶胞崩溃， 但是其外部的晶格保持完 整，出现了所谓的局部压缩，如图 15(a)所示。壁 间粘附是通过范德华相互作用发生的 [90][91][92] ， 没有发生 共价键的重排。如果进一步压缩，系统可能会显示更 多的局部压缩步骤，直到所有的晶胞完全崩溃，而且 每个局部压缩步骤都是不可逆的 [93][94][95] 。 图 15 蜂窝碳的压缩特性(a)蜂窝晶格的局部塌陷和蜂窝晶格压缩过程的放大(b)蜂窝结构在压缩过程中的应力-应变 曲线和能量-应变曲线(对应于(a)中的各个步骤) (c)破坏应变与晶格尺寸的关系(d)破坏应变与缺陷密度的关系 [51] 图经文献出版单位许可从文献【51】转载。 此外， 研究人员还分析了破坏应变对晶格尺寸的 依赖关系 [96,97] [103] 。在设计蜂窝碳材料时需要考虑这种各向异 性，并根据实际应用需求进行优化处理。 Qin Qin 等人 [104] 在 2019 年利用 MD 模拟方 法研究了蜂窝碳的力学性能，尤其是蜂窝碳在 x-y…”

Optimal Design of a Fiber-Reinforced Plastic Composite Sandwich Structure for the Base Plate of Aircraft Pallets In Order to Reduce Weight

“…Zaharia et al performed compression, three-point bending and tensile tests to evaluate the performance of light-weight sandwich structures with different core topologies [ 18 ]. Yan et al investigated the mechanical performance of the honeycomb sandwich structure with face-sheet/core debonding under a compressive load by experimental and numerical methods [ 19 ]. Baca Lopez and Ahmad estimated the best material sandwich structured arrangement design to enhance the mechanical properties [ 20 ].…”

Post-buckling behavior and failure analysis of asymmetric sandwich panels under uniaxial compression

“…Fink and Einzmann 18 proposed an optimized design to enhance the buckling resistance of ASPs. Yan et al 19 examined the influence of preset debonding defects and their size on the load bearing capacity and buckling modes of ASPs. Castanié et al 20 investigated the mechanical response of ASPs under shear, compression, and combined loads experimentally and numerically.…”