橡胶辅助增压在非热压罐成型工艺中的应用研究

Out-of-autoclave Curing Assisted by Rubber Pressurization

目的针对蒙皮带筋典型构件,在容易产生孔隙的加强筋底部放入橡胶增压,以优化应力场、减小孔隙缺陷。方法针对CFRP固化成型制度,进行红/蓝2种橡胶模量、热膨胀系数测试及双马树脂流变测试。基于材料测试数据及预浸料固化特征建立了固化前中后3类数值仿真模型,以对比不同橡胶在不同固化时期的增压效果。结果在固化前期,红、蓝橡胶均有增压作用,可使加强筋底部应力提高约5倍;在固化中期,红橡胶有显著增压作用,可使加强筋底部应力提高约9倍并改善应力梯度;在固化后期,橡胶难以发挥增压作用。结论红橡胶可显著发挥增压作用,有效解决加强筋固化成型前中期底部应力不足的问题;在CFRP固化前期,热膨胀系数是影响热应力的主要因素,在固化后期,模量为主要因素。通过对比多组仿真数据,明确了最优增压材料及最主要的材料属性,为解决OOA成型局部压力不足的问题提供了指导方向。

The work aims to introduce rubber pressurization into the position of insufficient pressure during the curing process of CFRP to optimize the stress field and reduce the pore defects of typical components of skin with reinforcement.Rub-ber modulus,coefficient of thermal expansion,and rheological properties of bismaleimide resin were tested for the CFRP curing molding system.Based on the material test data,three kinds of numerical simulation models with curing were established to compare the pressurization effect of different rubber in different curing periods.The simulation results showed that in the early stage of curing,both red and blue rubber had a pressurization effect,which could increase the stress at the bottom of the rein-forcing rib by about 5 times;In the middle stage of curing,red rubber had an excellent pressurization effect,which could in-crease the stress at the bottom of the reinforcing rib by about 9 times and improve the stress gradient.In the late stage of curing,rubber was difficult to exert its pressurization effect.In conclusion,red rubber can exert excellent pressurization effect and ef-fectively ameliorate the problem of insufficient stress at the bottom before and during the solidification molding of reinforcing ribs.In the early stage of CFRP curing,the coefficient of thermal expansion is the main factor affecting thermal stress,and the modulus is the main factor in the late stage of curing.Multiple sets of simulation data are compared to clarify the optimal boost-ing material and the most important material properties,providing guidance for solving the problem of insufficient local pressure in OOA molding.