全厚度缝合复合材料泡沫芯夹层结构力学性能研究与损伤容限评定

探索了全厚度缝合复合材料闭孔泡沫芯夹层结构低成本制造的工艺可行性及其潜在的结构效益。选用3 种夹层结构形式, 即相同材料和工艺制造的未缝合泡沫芯夹层和缝合泡沫芯夹层结构及密度相近的Nomex 蜂窝夹层结构, 完成了密度测定、三点弯曲、平面拉伸和压缩、夹层剪切、结构侧压和损伤阻抗/ 损伤容限等7 项实验研究。结果表明, 泡沫芯夹层结构缝合后, 显著提高了弯曲强度/ 质量比、弯曲刚度/ 质量比、面外拉伸和压缩强度、剪切强度和模量、侧压强度和模量、冲击后压缩(CAI) 强度和破坏应变。这种新型结构形式承载能力强、结构效率高、制造维护成本低, 可以在飞机轻质机体结构设计中采用。

Mechanical behavior and damage tolerance tests of compositesthrough-thickness stitched foam sandwich panels

This study explored the feasibility and potential benefits provided by the addition of through-thickness stitched composite closed-cell foam sandwich structures. For comparison purposes, unstitched foam and Nomex honeycomb core sandwich panels were produced using the same face sheets and manufacturing methodology. The density measurements, flexural testing, flatwise tensile and compression, core shear, edgewise compression, and damage resistance/damage tolerance tests were performed. The experimental results show significant increasing in the flexural stiffness to mass ratio, flexural strength to mass ratio, out-of-plane tensile and compression strength, core shear strength and modulus, edgewise compression strength and CAI strength and failure strain of the stitched foam sandwich structures. This innovative concept of stitched foam sandwich structures may be utilized in the aircraft design of lightweight and low-cost structures with higher load-carrying capability, lower manufacturing and maintaining cost.