Numerical simulation and experimental studies of mandrel effect on flow-compaction behavior of CFRP hat-shaped structure during curing process

CFRP hat-shaped structure is a typical stiffened structure used in aerospace field. In this work, aimed to provide a theoretical basis for manufacturing CFRP hat-shaped structure, the multi physical field coupling model considering influence of mandrel was established. Effect of mandrel on resin flow and fiber compaction during curing process was studied by simulation and experiment. Results showed that temperature and curing degree affected by mandrel can be negligible in hat-shaped structure, and the distribution of temperature and curing degree was relatively homogeneous. However, the behavior of resin flow and fiber compaction during curing process was not uniform. There was a larger gradient among resin flow, pressure, fiber volume fraction and laminate thickness. Presetting a suitable hole in mandrel can effectively improve the uniformity of resin flow and fiber compaction. By simulation analysis and optimization, the acceptable aperture of 11.5–12.5mm was obtained. Finally, the model and simulation developed in this study was validated by experiment. The reliability coefficient of 93.4–99.6% was obtained, which indicated a good agreement between simulation and experiment.