Compression properties of fabric fibers under dry and wet conditions
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摘要: 对干态和湿态两种工况下的碳纤维和玻璃纤维织物进行了压缩成型特性实验,利用黏弹性理论模型,分析了上述两种工况下压缩、应力松弛和回弹阶段的黏弹性曲线和黏弹性模型参数。通过分析两种工况下织物纱线压缩成型3个阶段的变形机制,阐述了产生上述差异的原因。结果表明,对于织物压缩阶段,当达到相同的最大成型压力时,湿态织物的成型厚度比干态的成型厚度略大。湿态织物的压缩时间比干态的压缩时间短,且织物规格越小,相差时间越少。湿态织物压缩阶段的时间常数小于干态织物对应值。对于织物应力松弛和回弹阶段,介质较少渗入织物间隙,织物变形过程基本相同,织物在两种工况下的成型厚度差值与回弹厚度差值十分接近。因此,湿态下织物的回弹厚度比干态下的回弹厚度略大。应力松弛和回弹阶段的时间常数基本相同。上述研究结果对纤维增强树脂基复合材料的成型工艺具有了一定的指导意义。Abstract: The experiments of carbon fabrics and glass fiber fabrics under both dry and wet conditions were conducted for exploring the compression characteristic. By using the viscoelastic theory model, the viscoelastic curves and viscoelastic model parameters of the compression, stress relaxation and rebound stages under the two aforementioned conditions were analyzed. The deformation mechanism at three compression stages of the yarn was analyzed, and the corresponding explanations for these differences were presented. The results show that the forming thickness of wet fabrics is slightly larger than dry fabrics when the same maximum forming pressure is loaded at the compression stage. The compression time of wet fabrics is shorter than that of dry fabrics, and the yarn specification is much smaller. Besides, the difference of the time is not obvious. The time constant at the compression stage for wet fabrics is less than the corresponding value for dry fabrics. At the stress relaxation and rebound stage, a small amount of media penetrates into the fabric gaps, while the change process of the fabrics is basically the same. The forming thickness difference and rebound thickness difference under the two conditions are very close. Correspondingly, the rebound thickness of wet fabrics is finally slightly larger than that of dry fabrics. The time constants of stress relaxation and rebound are basically the same. These results provide important guidance for the forming process of fiber reinforced resin matrix composites.
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Key words:
- viscoelasticity /
- wet fabric /
- forming thickness /
- rebound thickness /
- time constants
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