共查询到19条相似文献,搜索用时 296 毫秒
1.
树脂膜熔渗工艺(RFI)是一种新型的复合材料成型工艺.为了更深入了解树脂膜熔渗工艺过程中充模阶段的控制参数对制品质量的影响,避免制品出现空斑、充模不完全等问题,针对该工艺过程中树脂在复杂形状预制件中的流动行为进行了分析,在达西定律基础上建立了二维等温流动控制方程,利用有限元/控制体方法建立了数值分析模型,编制了FORTRAN程序进行模拟运算,并讨论了流动过程中施加的压力对充模时间的影响.由计算实例可见,所编制程序能够很好地预测树脂膜熔渗工艺过程中充模时间、各个时刻树脂的流动前沿位置及模腔中的压力分布. 相似文献
2.
3.
为优化复杂预成型体结构的液体成型工艺,基于有限元法/生死节点法模拟了复合材料液体模塑成型过程树脂流动,并针对典型矩形平板、圆板结构、I型加筋壁板充模过程进行了仿真与验证。结果表明:典型矩形平板和圆板结构的充模过程模拟结果与理论解一致性较好,验证了生死节点法跟踪树脂流动前锋的有效性。含有方腔的变厚度圆柱体和正方体三维实体结构的充模过程模拟验证了有限元方法对三维结构的适用性。基于有限元法/生死节点法的液体充模过程模拟方法对于复杂求解区域具有更好适应性,可用于复杂实体结构的液体模塑成型工艺过程树脂流动规律预测、指导模具设计及工艺优化。 相似文献
4.
采用可视化流动实验方法研究了高渗透率导流介质对真空导入模塑工艺中树脂流动行为的影响。结果表明: 导流介质能较大幅度地减少树脂的充模流动时间, 且充模时间随着导流介质使用比例的增加而呈线性减少的关系; 导流介质的提速作用随着预成型体厚度的增加而逐渐减弱; 预成型体上下表面树脂流动前沿位置差距与预成型体厚度呈良好的线性增加关系, 说明导流介质的影响作用具有明显的厚度效应。厚度效应原理为真空导入模塑工艺过程的参数优化和保证制品质量提供了理论依据。 相似文献
5.
6.
在树脂基复合材料的成型工艺中大多涉及到树脂的流动过程, 而树脂压力是反映这一过程的重要参数, 监测成型过程中树脂压力的变化可以为工艺参数的选择和构件质量的控制提供指导。本文中针对热压工艺, 根据液体传压原理和特点, 自行研制了复合材料成型过程树脂压力测试系统, 对系统的精度和动态响应性能进行了研究, 并以该系统为测试手段, 初步研究了玻璃纤维单向层板中树脂压力的变化规律。结果表明, 该系统具有准确度高和动态响应敏感的特点, 满足热压成型过程树脂压力的测试要求, 为研究工艺过程树脂流动行为提供了有力的测试与验证手段。 相似文献
7.
针对VARTM工艺的特点,建立了充模过程树脂流动和预成型体变形行为数学模型。提出了基于混合网格方法的VARTM充模仿真算法,在该算法中,模具型腔几何模型进行二维或三维网格划分,在每个真空袋表面单元上增加一个一维附属单元,用于在仿真过程中实时地吸收或挤出因真空袋变形而产生的局部树脂体积变化,形成混合网格仿真模型;求解过程中,对树脂流动和预成型体变形分别进行求解后,基于上述混合网格模型进行两者耦合操作,实现了仿真精度和速度的统一。搭建了VARTM充模实验平台,进行了一维充模实验,通过仿真结果与实验测量结果对比,验证了本文算法的正确性。最后,通过三维仿真算例,验证了算法对三维复杂结构和顺序浇口策略仿真的可行性。 相似文献
8.
9.
《高分子材料科学与工程》2015,(11)
采用"长条"模型代替泡沫中沿缝线方向树脂流动模型并对其等效渗透率及孔隙率进行计算;然后用PAM-RTM软件对缝合泡沫夹芯结构真空辅助树脂传递模塑成型(VARTM)工艺树脂充填过程进行数值模拟,最后建立了流动可视化实验装置对模拟结果进行实验验证。对比模拟与实验结果表明,模拟与实验完成整个充填过程的时间非常接近,并且树脂在预成型体中流动方式及在预成型体上、下面板流动状态的数值模拟与实验结果也非常地一致。故建立的"长条"模型及其相关参数的计算是合理的,可以用来准确地预测缝合泡沫夹芯结构VARTM工艺树脂充填过程。另外,树脂在上面板流动前沿在沿宽度方向较为统一,而树脂在下面板流动前沿呈现锯齿状,容易产生空隙及干斑等缺陷,影响制品的质量。 相似文献
10.
11.
In the autoclave process, resin flow is a primary mechanics for the removing of excess resin and voids entrapped in the laminate
and obtaining a uniform and void free composite part. A numerical method was developed to simulate the resin flow in the laminate
and the bleeder, and the effects of ‘bleeder flow’ on the resin flow and fiber compaction were conducted. At the same time,
fiber distribution in the cured laminates was investigated by both experiments and simulations for the CF/Epoxy and CF/BMI
composites. The data of the experiments and simulations demonstrated that fibers consolidated and reconsolidated in the laminate
and it was impacted by the viscosity and gel time of the resin system. Compared to the post study in which only resin flow
in the laminate are considered, these results will deepen the understanding of the consolidation process, resin pressure variation
and void control during the autoclave process, which is valuable for the study of the performance of composite parts, provided
that fiber distribution does affect some properties of composite material. 相似文献
12.
《Composites Science and Technology》2006,66(7-8):1067-1080
A new methodology is presented to simulate mold filling in resin transfer molding (RTM) using a combination of the level set and boundary element methods (BEMs). RTM is a composite manufacturing process where a liquid resin is injected in a closed rigid mold containing a dry fibrous reinforcement. Process simulation is motivated by the importance of tracking accurately the motion of the flow front during the mold filling stage. The BEM solves the equation governing the resin flow and the level set method is implemented to track the resin front in the mold. This formulation opens up new opportunities to improve RTM flow simulations and optimize injection molds. The present paper focuses on isothermal resin flow in undeformable porous medium. The implementation of the numerical algorithm is described and several examples of two-dimensional filling with single or multiple injection gates are presented. The robustness of the coupling and the ability to predict accurately the position of the front by this new model are discussed. It is also shown how dry spot formation can be tracked precisely during the simulation and how a generalization of this approach allows predicting resin flow across obstacles. 相似文献
13.
14.
Fuhong DAI Shanyi DU Boming ZHANG Dianfu WAN Ceater for Composite Materials Harbin Institute of Technology Harbin China 《材料科学技术学报》2004,20(3):335-340
A new method to track resin flow fronts, referred to as the topological interpolated method (TIM), which is based onfilling states and topological relations of adjacent nodes was proposed. An experiment on the mould filling process wasconducted. It was compared with exact solutions and the experimental results, and good agreements were observed.Numerical and experimental comparisons with the conventional contour mathod were also carried out, and it showedthat TIM could enhance the local accuracy of flow front solutions with respect to the contour method when mergingflow fronts and resin approaching the mold wall were involved. 相似文献
15.
为了预测在固化度、温度和固化放热共同作用下, 树脂体系的黏度随时间的变化, 提出了一种确定反应性树脂体系黏度随时间变化关系的新方法。该方法从等温黏度-时间曲线和固化度-时间曲线出发, 分别得到黏度-固化度关系和黏度-温度关系, 从而将影响反应性流体黏度变化的两个主要因素温度和固化程度分离开来。基于反应性树脂体系的局部绝热假设, 将反应性树脂体系的固化放热引入到黏度变化关系中, 得到反应性树脂体系黏度在固化度、温度和固化放热共同作用下的黏度-时间关系。黏度预测值与用旋转黏度计测量值的黏度变化趋势具有高度的一致性, 可以应用此方法实现对实际环境中考虑固化反应热效应的反应性树脂体系黏度的预测。 相似文献
16.
17.
在缝合泡沫夹芯结构复合材料的泡沫中嵌入轻质的加强筋板,可以在不增加缝合密度并且在只增加较少质量的前提下,增强复合材料制品整体的强度和刚性。文中对真空辅助树脂传递模塑成型(VARTM)工艺树脂在嵌入加强筋的缝合泡沫夹芯结构复合材料预成型体中充填过程进行模拟和验证研究。采用一种矩形流道模型代替沿加强筋与泡沫空隙间的树脂流动,并对其等效渗透率及孔隙率进行计算;通过PAM-RTM软件模拟了嵌入加强筋板的缝合泡沫夹芯结构VARTM工艺的树脂充填过程,并建立了流动可视化实验装置与模拟对比,结果表明模拟与实验相当吻合。而模拟与实验的结果均表明加强筋的引入可以在局部加强树脂沿厚度方向的流动,但是会延缓树脂对整个预成型体的充填。 相似文献
18.
Curing simulation by autoclave resin infusion 总被引:5,自引:0,他引:5
D. C. Blest S. McKee A. K. Zulkifle P. Marshall 《Composites Science and Technology》1999,59(16):1762-2313
This paper deals with the modelling and simulation of resin flow, heat transfer and the curing of a multilayer thermoset composite by the resin film infusion process. For approximately isothermal flows, the model is based on Darcy's Law and Stoke's equations where a similarity solution is obtained and subsequently used in a two-dimensional convection-diffusion heat equation coupled with a rate of cure equation. A finite difference scheme is applied to the energy equation on a moving grid and simulations for varying laminate thicknesses and number of plies are performed. 相似文献
19.
Wen-Bin Young 《Applied Composite Materials》2013,20(6):1305-1319
Vacuum assisted resin transfer molding (VARTM) is one of the important processes to fabricate high performance composites. In this process, resin is drawn into the mold to impregnate the fiber reinforcement to a form composite. A resin distribution layer with high permeability was often introduced on top of the fiber reinforcement to accelerate the filling speed. Due to the difference of the flow resistance in the resin distribution layer and the reinforcement as well as the resulting through thickness transverse flow, the filling flow field is intrinsically three-dimensional. This study developed a two-layer model with two-dimensional formulation to simulate the filling flow of the VARTM process with a resin distribution layer. Two-dimensional flow was considered in each layer and a transverse flow in the thickness direction was estimated between the two layers. Thermal analysis including the transverse convection was also performed to better simulate the temperature distribution. 相似文献