工型加筋结构模具方案对共固化过程树脂压力及成型质量的影响

INFLUENCES OF MOLD SCHEME ON RESIN PRESSURE AND PROCESSING QUALITY OF CO-CURED I-STIFFENED SKIN

以碳纤维/双马树脂复合材料工型加筋结构为研究对象,研究了模具方案对热压罐共固化过程树脂压力及成型质量的影响。对筋条两侧的模具采用了三种方案,即铝模/铝模、橡胶软模/铝模、拐角区预浸料增强橡胶软模/铝模。采用自主建立的树脂压力在线监测系统对三种模具方案下工型加筋结构内部树脂压力分布进行研究,进而结合制件尺寸及内部缺陷情况,分析模具方案对树脂流动、模具与预浸料铺层贴合程度及密实过程的影响。结果表明:橡胶软模能显著提高模具与预浸料的贴合程度,从而提高压力传递效率和密实程度;软模拐角区刚度对制件成型质量影响显著,拐角区刚度过低则成型中模具发生较大形变,不利于另一侧铝模与预浸料贴合以及制件尺寸精度的保证;适当提高软模拐角区刚度可提高密实压力均匀性和制件成型质量;适当刚度的橡胶软模和金属刚模配合方案对于加筋壁板结构的共固化工艺较为适用。

In this paper,the influences of mold scheme on resin pressure distribution and processing quality of carbon fiber/bismaleimide resin I-stiffened skin fabricated by autoclave co-cured process were studied. Three kinds of mold schemes for two sides of stiffener were designed,including aluminum mold/aluminum mold,rubber mold/aluminum mold and rubber mold with corner reinforced by prepreg/aluminum mold. And resin pressure distribution inside I-stiffened skin processed with these three mold schemes was investigated by means of self-developed resin pressure online monitoring system. Furthermore,considering dimension and inner defects of I-stiffened skin,the influences of mold scheme on resin flow,fitting state between mold and prepreg stack and compaction process of prepreg stack were studied. The results show that rubber mold significantly improves fitting degree between mold and prepreg stack,thus increasing pressure transferring efficiency of mold and compaction degree of composite. The stiffness of the corner in rubber mold has a significant impact on processing quality of I-stiffened skin. Too low corner stiffness results in larger deformation of mold during processing,which is detrimental to fitting degree between aluminum mold placed at the other side and prepreg stack. It also leads to decrease in dimensional accuracy of I-stiffened skin. Nevertheless,appropriately increasing the corner stiffness of rubber mold can improve uniformity of compaction pressure and processing quality. The mold scheme,which uses rubber mold with reasonable stiffness and metal mold,is suitable for fabricating stiffened skin structure using autoclave co-cured process.