Prediction of process-induced deformation in CFRP multispar flaps using sequentially coupled thermomechanical analysis considering fabric patterns and stacking sequences

This study presents a sequentially coupled thermomechanical FE-based approach for analyzing process-induced deformation (PID) in CFRP multispar flaps during the curing cycle. The proposed method enables a detailed investigation of curing behaviors by incorporating critical material characteristics, including complex curing properties and fabric patterns. A two-step simulation framework, integrating heat transfer and mechanical analyses, was employed to evaluate the effects of thermal gradients, cure kinetics, and thermochemical deformation on PID. The results revealed significant temperature gradients influencing the degree of cure (DoC) and PID throughout the curing cycle. By the end of the process, the temperature distribution became uniform, and the DoC stabilized at approximately 0.91. PID behaviors transitioned progressively throughout the curing stages, with thermal expansion prevailing during early deformations, while chemical and thermal shrinkage became the primary factors in subsequent stages. These findings indicate that minimizing deformation necessitates not only the optimization of geometric designs but also the precise adjustment of curing profiles and fabric patterns informed by the thermochemical behavior of materials. The methodology proposed in this study facilitates the strategic optimization of curing properties, fabric characteristics, and manufacturing parameters, enabling effective PID control. Furthermore, this study offers valuable insights into enhancing the design and manufacturing processes of aerospace composite structures, ensuring greater structural integrity, dimensional stability, and overall performance.