热压罐工艺复合材料双侧硬模成型传压机制及工艺质量影响因素

PRESSURE TRANSFER FOR COMPOSITE AUTOCLAVE PROCESS WITH TWO-SIDE RIGID MOLD AND THE INFLUENCING FACTORS ON ITS PROCESS QUALITY

本文围绕复合材料层板双侧硬模成型方法,剖析了模具型面公差对复合材料工艺质量的影响,模拟分析了模具型面公差和预浸料变厚度对应力分布状态、树脂渗流的作用,并利用自主建立的树脂压力在线测试系统验证了双侧硬模成型中的应力分布状态。结果表明,双侧硬模成型复合材料时,模具公差对层板质量影响显著,模具负公差区易于产生孔隙、分层等缺陷,正公差区层内与层间厚度均低于负公差区;树脂压力在线测试与模拟分析均表明,模具公差与预浸料变厚度可造成双侧硬模加压中的应力非均匀分布,这是造成层内及层间厚度差异、孔隙等缺陷的主因;预浸料厚度增加、模具型面与预浸料叠层的间隙区填充程度增大有利于减小预浸料压力的非均匀性。研究结果对高型面精度复合材料制备与工艺质量控制具有重要指导意义。

This paper focuses on the autoclave process by using two-side rigid steel mold. The influence of mold tolerance on the process quality of composite laminate was investigated. The effects of mold tolerance and prepreg thickness difference on stress distribution and resin flow inside prepreg were revealed by finite element analysis. Furthermore, a self-designed resin pressure online monitoring system was used to verify the stress distribution caused by two-side rigid mold. The results show that the process quality is closely related to mold tolerance when the two-side rigid mold is used. Void and delamination are easy to be caused at the negative tolerance area. The lamina and interlaminar thicknesses at positive tolerance area are smaller than those at negative tolerance area. Both resin pressure measurement and finite element analysis indicate that mold tolerance and prepreg thickness difference may cause uneven stress distribution, which are also the main reasons for manufacturing defects. Thicker prepreg and full impreg- nation of the gap between mold and prepreg are beneficial to improve stress distribution. These results may contribute to the manufacturing and quality control of advanced composite with high surface precision.