Experimental and numerical study of the spring-in of angled brackets manufactured using different resins and fiber textiles
Experimental and numerical study of the spring-in of angled brackets manufactured using different resins and fiber textiles
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DOI：
10.1177/0021998319855423
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发表时间：
2019-06
影响因子：
2.9
通讯作者：
A. Bernath;Fabian Groh;W. Exner;C. Hühne;F. Henning
中科院分区：
文献类型：
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作者：
A. Bernath;Fabian Groh;W. Exner;C. Hühne;F. Henning
复合材料结构的工艺引起的变形通常导致公差的违反，使得部件的组装困难且昂贵。因此，它可以抑制高性能复合结构的成本有效的大规模生产。加工引起的变形通常是由零件的弯曲区域由于回弹引起的。主要驱动因素是树脂的化学收缩以及脱模后冷却期间纤维和树脂的热膨胀。两者都有助于残余应变，并因此导致所制造的部件的变形。在许多研究中已经讨论了弹簧现象。然而，在制造和试样性能的变化抑制了详细的比较结果。因此，很难分离出主要的影响参数。在这里，我们展示了使用完全相同的实验装置和层压板配置，但不同的树脂和纤维类型制造的样本的弹簧结果。因此，有可能将固化温度和各个树脂的最大可实现玻璃化转变温度的相互作用确定为主要影响因素。此外，它表明，所研究的树脂的性能没有很大的不同，在热膨胀和化学收缩方面。此外，后者使用两种不同的技术进行测量，以便进行比较。数值弹簧预测显示良好的精度在整个调查标本配置。发现的局限性是纤维纺织品的缝纫的影响和模型的灵敏度逐渐变化的铺叠。此外，不同的均匀化技术进行比较方面的弹簧在预测精度。
Process-induced distortion of composite structures often leads to a violation of tolerances, making the assembly of components difficult and expensive. It therefore can inhibit a cost-effective mass production of high-performance composite structures. Process-induced distortion is often introduced by curved regions of a part due to spring-in. Main drivers are chemical shrinkage of the resin and thermal expansion of both fiber and resin during cooling after demolding. Both contribute to residual strains and consequently lead to distortion of the manufactured part. The spring-in phenomenon has been already addressed in many studies. However, variations in manufacturing and specimen properties inhibit a detailed comparison of the results. Hence, it is difficult to isolate major influencing parameters. Here we show spring-in results of specimens that were manufactured using the very same experimental setup and laminate configuration but different resin and fiber types. It is therefore possible to identify the interaction of the curing temperature and the maximum achievable glass transition temperature of the individual resins as a major influencing factor. Furthermore, it is shown that the properties of the investigated resins do not differ largely in terms of thermal expansion and chemical shrinkage. Moreover, the latter was measured using two different techniques to enable a comparison. Numerical spring-in prediction revealed good accuracy throughout the investigated specimen configurations. Limitations found are the influence of the sewing of fiber textiles and the sensitivity of the model to gradual changes of the layup. Moreover, different homogenization techniques are compared with regard to spring-in prediction accuracy.