缝合夹层结构复合材料树脂传递模塑成型工艺充模仿真

Filling simulation of stitched sandwich composite by resin transfer molding process

对复合材料与金属经缝合连接形成的夹层结构板的树脂传递模塑成型(RTM)工艺进行了充模模拟研究。首先通过实验和数值计算的方法,分别获得缝合夹层结构织物和芯层孔洞的渗透率;随后,建立能够反映缝孔内流动情况的二维和三维简化模型,进行RTM充模仿真,讨论不同工艺参数对成型流动的影响;最后通过成型实验验证工艺的可行性。缝线与孔洞直径之比为0.3～0.8时,孔洞渗透率随缝线直径的增大而减小,预制体织物渗透率与孔洞渗透率相差两个数量级;缝孔内容易产生缺陷,没有缺陷的区域随着注射压力的增加、孔洞密度和芯层厚度的减小而增大,在芯层表面沿每排孔洞单向开槽能够改善树脂在孔洞内的浸润;线注射时,树脂整体流动情况优于点注射,而点注射时,将进胶口设置在一角,能够减少表面干斑。

The resin flow in composite and metal stitched sandwich structure during resin transfer molding(RTM)process was simulated.First,the permeability of fabric and holes of stitched sandwich structure was obtained respectively through the experiment and numerical calculation.Then,the two-dimensional and three-dimensional simplified models that can reflect the flow in holes were established to simulate the resin flow in RTM process.The influence of different process parameters on molding process was discussed.Finally,a molding experiment was made to verify the simulation results.When the ratio of the suture diameter to the hole diameter is within 0.3-0.8,the permeability of the holes decreases with the increasing diameter of the suture.The difference between the permeability of the fabric and the holes is two orders of magnitude.Dry spots are easily produced in holes,so the inlets and outlets should be set to ensure the resin flow through the holes from one side of the core layer to the other side.The area with no defects increases with the increasing injection pressure and decreases with the increasing holes pacing and thickness of the core layer.The unidirectional slotting along each row of holes on core layer can improve the infiltration quality in the holes.When the inlet is a line,the flow of the resin is good.And when the inlet is a point,setting the inlet to the corner can reduce the dry spots on the surface.