Process-induced shape distortion is generated in curved composite parts. Although the distortion mechanisms have been understood through considerable previous efforts, they were validated by indirect methods such as shape measurement, leaving some room for discussion. The present work developed a novel direct method using in-situ fiber-optic-based monitoring of through-thickness normal and shear strains. This method was applied to an L-shaped CFRP part and the result indicated that chemical cure shrinkage induces shear deformation. Moreover, the phenomenon gradually changed from shear-dominated to bending-dominated deformation as curing proceeded. The shear-lag analysis developed in previous work was then extended to L-shaped parts. The effects of flanges and edge constraints were investigated based on analytical and experiment results. The analysis also proposed a spring-in prediction scheme that uses strain monitoring results as inputs. The prediction agreed with the experiment result, indicating that cure-induced shear deformation should be considered for highly precise distortion prediction.

在弯曲的复合零件中会产生过程引起的形状变形。尽管通过大量的先前努力已经了解了失真机制，但是它们已通过诸如形状测量之类的间接方法进行了验证，因此仍有一定的讨论空间。本工作开发了一种新颖的直接方法，该方法使用基于光纤的厚度方向法向应变和剪切应变进行监测。该方法应用于L形CFRP零件，结果表明化学固化收缩会引起剪切变形。而且，随着固化的进行，该现象逐渐从剪切为主变形变为弯曲为主变形。然后将先前工作中开发的剪切滞后分析扩展到L形零件。基于分析和实验结果，研究了法兰和边缘约束的影响。分析还提出了使用应变监测结果作为输入的弹入预测方案。该预测与实验结果吻合，表明对于高精度的变形预测，应考虑固化引起的剪切变形。