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作为复合材料液态成型技术(LCM:Liquid Composites Moulding)中的一种,液体树脂灌注成型工艺(LRI:Liquid Resin Infusion)以其良好的发展前景已经越来越多地被先进复合材料制造产业所关注。为了提高对液体树脂灌注成型工艺的认知并从而达到对其良好的控制度,需要在实际制造工艺进行中监测其重要的制造参数,如纤维层的应变、树脂的流动情况等等。在对整体工艺过程产生尽可能小的影响和干扰的前提下,一种微型热电偶配合光纤传感器的简单耦合测量技术被用来在灌注过程中监测碳纤维层平均应变和树脂温度。碳纤维层平均应变的测量反映了液体树脂灌注成型工艺不同阶段下(浸润阶段、固化阶段、冷却阶段)碳纤维层特性的变化。另一方面树脂温度的监测不仅可以有效地估测液态树脂灌注时间而且可以观察到树脂流动前沿的特性。为了进一步验证碳纤维层平均应变这一间接测量结果,一种特殊的微型电子应变仪会同时应用到该实验中来。研究表明:液体树脂用550 s浸润完全整个纤维层,并且在该阶段整个纤维层一直处于压缩状态。在接下来的75 min中的树脂固化阶段纤维层压缩变形量达到了最大值。冷却阶段会释放出少部分的压缩应力,但还有一部分残余应力出现在成型件中。最终间接与直接的两种测量方法所得到的实验结果的比较与验证会更加完善对复合材料液态成型技术的研究。
As one of Liquid Composites Molding (LCM), Liquid Resin Infusion (LPC) has been paid more and more attention by the advanced composite materials manufacturing industry for its good development prospects . In order to improve the recognition of the liquid resin infusion molding process and thus achieve a good degree of control, important manufacturing parameters such as the strain of the fiber layer, the flow of the resin and the like need to be monitored in the actual manufacturing process. A simple coupled measurement technique with a miniature thermocouple coupled with a fiber optic sensor is used to monitor the mean strain and resin temperature of the carbon fiber layer during the infusion process with minimal impact and disruption to the overall process. The measurement of the average strain of the carbon fiber layer reflects the change of the properties of the carbon fiber layer at different stages of the liquid resin infusion molding process (wetting stage, solidifying stage and cooling stage). On the other hand, the monitoring of the resin temperature can not only effectively estimate the liquid resin infusion time but also observe the characteristics of the resin flow front. In order to further verify the indirect measurement of the average strain of the carbon fiber layer, a special micro-electronic strain gauge will be applied to the experiment at the same time. The results show that the liquid resin completely infiltrated the entire fiber layer with 550 seconds, and the entire fiber layer was in compression at this stage. In the next 75 min in the resin curing stage, the maximum compressive deformation of the fiber layer. The cooling stage will release a small part of the compressive stress, but there are still some residual stress in the molded parts. The final indirect and direct measurement of the two methods obtained by comparing the experimental results and verification will be more perfect composite material liquid forming technology research.