【摘要】 针对大厚度复合材料固化过程中的热冲击和热壳核效应,提出分层自阻电热固化工艺设计方法,用以缓解固化热冲击、降低厚向温差和缩短固化周期。建立多物理场耦合的分层自阻电热固化有限元模型,预测在特定分层工艺参数下固化度和厚向温度分布。在有限元模型基础上,建立径向基网络代理模型,并通过遗传算法对固化过程中热冲击峰值温度、厚向最大温差、固化周期进行多目标优化,最终获得优化的多层独立温控工艺参数。基于多通道自阻电热平台进行了分层自阻电热固化试验。试验结果表明,采用优化的分层新工艺的固化热冲击峰值温度降低到玻璃化转变温度以下的132.8℃。相比烘箱固化过冲温度减小19.7℃,降低了60.6%;相比整体自阻电热固化和推荐工艺的分层自阻电热固化分别减小54.0%和34.7%。固化周期减少约33min,缩短19.6%。优化设计的分层自阻电热工艺可有效降低固化反应热冲击,提高大厚度复合材料厚度方向温度均匀性。更多还原

【Abstract】 Aiming at the thermal overshoot and thermal shell-core effect during the curing of thick composite, a layered self-resistance electric heating(L–SRE) process design method is proposed to alleviate the thermal overshoot, reduce the through-thickness temperature difference, and shorten the curing time. In this paper, a multi-physical coupling finite element model(FEM) of L–SRE process is established to predict the degree of curing and the through-thickness temperature distribution under specific layering process parameters. Based on the FEM, a radial basis neural network surrogate model(RBF) is established. The genetic algorithm(GA) is used to optimize the peak temperature of thermal overshoot, the maximum through-thickness temperature difference, and the curing time during the whole process to obtain optimal parameters. Finally, the optimized multi-layer independent temperature control process parameters are obtained. Based on a multi-channel self-resistance electric heating(SRE) platform, L–SRE curing experiments are carried out. The experimental results show that the peak temperature of thermal overshoot using the new process is reduced to 132.8℃ below the glass transition temperature. Compared with the oven, the overshoot temperature is reduced by 19.7 ℃, which is a 60.6% reduction; Compared with the integrated SRE and the recommended process of L-SRE, the overshoot temperature are reduced by 54.0% and 34.7% respectively. The curing time is reduced by nearly 33 min, which is a 19.6% shorter. The optimized L–SRE process parameters can effectively reduce the thermal overshoot and improve the temperature uniformity through thickness.更多还原