Koutsomichalis Aggelos, Kalampoukas Thomas, Mouzakis Dionysios E
Mechanics of Materials and Engineering Lab, Hellenic Airforce Academy, Tatoion Airforce Base, GR13672 Acharnes, Greece.
Mechanics of Materials Laboratory, Sector of Mathematics and Engineering Applications, Hellenic Army Academy, GR16672 Vari, Attika, Greece.
Polymers (Basel). 2021 Apr 6;13(7):1178. doi: 10.3390/polym13071178.
The purpose of this study was to manufacture hybrid composites from fabrics with superior ballistic performance, and to analyze their viscoelastic and mechanical response. Therefore, composites in hybrid lay-up modes were manufactured from Vectran, Kevlar and aluminum fiber-woven fabrics through a vacuum assisted resin transfer molding. The specimens were consequently analyzed using static three-point bending, as well as by dynamic mechanical analysis (DMA). Apart from DMA, time-temperature superposition (TTS) analysis was performed by all available models. It was possible to study the intrinsic viscoelastic behavior of hybrid ballistic laminates, with TTS analysis gained from creep testing. A polynomic mathematical function was proposed to provide a high accuracy for TTS curves, when shifting out of the linearity regimes is required. The usual Williams-Landel-Ferry and Arrhenius models proved not useful in order to describe and model the shift factors of the acquired curves. In terms of static results, the highly nonlinear stress-strain curve of both composites was obvious, whereas the differential mechanism of failure in relation to stress absorption, at each stage of deformation, was studied. SEM fractography revealed that hybrid specimens with Kevlar plies are prone to tensile side failure, whereas the hybrid specimens with Vectran plies exhibited high performance on the tensile side of the specimens in three-point bending, leading to compressive failure owing to the high stress retained at higher strains after the maximum bending strength was reached.
本研究的目的是用具有卓越防弹性能的织物制造混杂复合材料，并分析其粘弹性和力学响应。因此，通过真空辅助树脂传递模塑工艺，用Vectran、凯夫拉尔和铝纤维编织织物制造了混杂铺层模式的复合材料。随后，对试样进行了静态三点弯曲分析以及动态力学分析（DMA）。除了DMA之外，还采用所有可用模型进行了时间-温度叠加（TTS）分析。通过蠕变试验获得的TTS分析，能够研究混杂防弹层压板的固有粘弹性行为。当需要偏离线性区域时，提出了一个多项式数学函数以提高TTS曲线的精度。事实证明，常用的威廉姆斯-兰德尔-费里模型和阿伦尼乌斯模型对于描述和模拟所获曲线的移动因子并无用处。就静态结果而言，两种复合材料的高度非线性应力-应变曲线很明显，同时研究了在每个变形阶段与应力吸收相关的失效微分机制。扫描电子显微镜断口分析表明，带有凯夫拉尔层的混杂试样易于在拉伸侧失效，而带有Vectran层的混杂试样在三点弯曲试验中在试样的拉伸侧表现出高性能，在达到最大弯曲强度后，由于在较高应变下保留了高应力，导致压缩失效。
