Enhancement of flow in VARTM using localized induction heating
Enhancement of flow in VARTM using localized induction heating
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DOI：
10.1016/s0266-3538(03)00179-9
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发表时间：
2003-11-01
影响因子：
9.1
通讯作者：
Pitchumani, R
中科院分区：
文献类型：
--
作者：
Johnson, RJ;Pitchumani, R
真空辅助树脂传递模塑(VARTM)过程中的一个关键步骤是反应树脂对多孔预制件的渗透。为了实现完全的预制件饱和和无空隙填充，实时流量控制通常是必不可少的。然而，预制件中的局部渗透率变化对流动控制努力提出了挑战。在文献中显示，使用对入口参数的操纵的控制策略在局部预制件可变性区域中的流动可控性方面受到限制，特别是在远离受控注射端口的位置。本文探索了一种创新的方案，即使用感应加热作为一种局部降低树脂粘度的方法，以抵消预制件中这种局部低渗透区的影响。为此，本文提出了VARTM过程中存在感应加热时非等温流动的过程模型。用实验验证的工艺模型进行了工艺模拟，研究了感应加热位置、感应加热功率和真空度等工艺参数对低渗透区和高渗透区三种不同渗透率的异质预制件几何形状的影响。这些研究的结果以加工窗口和加工图的形式给出，这表明感应加热能够减少VARTM过程中空洞和干斑的形成。(C)2003爱思唯尔有限公司。保留所有权利。
A critical step in the vacuum assisted resin transfer molding (VARTM) process is the permeation of a porous preform by the reactive resin. A real time flow control is often imperative to achieve complete preform saturation and void-free fill. Local permeability variations in the preform, however, challenge the flow control endeavor. Control strategies that use manipulation of the inlet port parameters are shown in the literature to be limited in the controllability of flow in regions of localized preform variability, particularly at locations away from the controlled injection ports. This paper explores an innovative scheme of using induction heating as a method of locally reducing the resin viscosity to counteract the effects of such localized low permeability regions within the preform. Toward this end, the paper presents a process model for nonisothermal flow during the VARTM process, in the presence of induction heating. The process model, validated with experiments, is used to conduct process simulations to investigate the effects of processing parameters such as induction heating location, induction heating power level, and vacuum level on three heterogeneous preform geometries with varying permeability ratios between the low permeability and high permeability regions. Results of these studies are presented in the form of processing windows and processing maps, which show that induction heating is capable of reducing void and dry spot formation during the VARTM process. (C) 2003 Elsevier Ltd. All rights reserved.