VARI成型V型构件固化变形和影响因素分析

复合材料在成型过程中会伴随着复杂的热化学和物理变化,此现象会导致复合材料内部的残余应力积累并进一步使复合材料在脱模后产生固化变形。采用顺序耦合热应力的方法建立了预测复合材料固化变形的三维有限元模型,对真空辅助成型(VARI)的复合材料V型构件的固化变形进行了数值模拟和试验验证,并进一步分析了固化温度、对流换热系数、构件厚度等因素对复合材料V型构件的影响。模拟结果表明,复合材料V型构件的回弹角会随着固化温度和对流换热系数的升高而增大,随着构件的厚度增加而减小。固化温度从150℃升高至190℃,回弹角增加了72%;对流换热系数从1 W/(m2 K)升高至100 W/(m2 K),回弹角增加了15%;构件厚度从2.4 mm增加至4.8 mm,回弹角减小了43%。

Analysis on Cure-induced Deformation and Influencing Factors of V-shaped Composite Formed by VARI Process

Composite materials are accompanied by complex thermochemical and physical changes during the molding process,which can lead to the accumulation of residual stresses inside the composite and further cause the composite to undergo cureinduced deformation after demolding.The three-dimensional finite element model for predicting the cure-induced deformation of composites was established by sequential coupled heat-stress method.The cure-induced deformation of V-shaped composite formed by VARI process was numerically simulated and tested.The influence of curing temperature,heat transfer coefficient,component thickness and other factors on the V-shaped composite were further analyzed.The simulation results show that the spring-in angle of the V-shaped composite increases with the increase of curing temperature and convective heat transfer coefficient,and decreases with the increase of the thickness of the component.The curing temperature increases from 150℃to 190℃,the spring-in angle increases by 72%.The convective heat transfer coefficient increases from 1 W/(m2·K)to 100 W/(m2·K),the spring-in angle increases by 15%.Thickness increases from 2.4 mm to 4.8 mm,the spring-in angle decreases by 43%.