玻纤增强注塑成型构件结构强度研究

发布时间：2018-01-03 12:28

本文关键词：玻纤增强注塑成型构件结构强度研究　出处：《湖南工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着轨道交通行业的迅速发展,玻纤增强复合材料已得到了广泛的应用,而注塑成型是经济、高效和广泛应用的主要技术手段之一。由于玻纤增强注塑成型构件内部玻纤取向分散,若要准确预测和分析其承载特性和结构强度,就不能不考虑因玻纤取向分布而产生的材料各向异性性能。本文从影响玻纤增强注塑成型构件的力学性能出发,考虑玻纤质量分数、玻纤间相互作用、玻纤长径比以及注塑工艺参数的影响,基于复合材料力学理论建立玻纤均质化模型,对玻纤增强复合材料的正交各向异性宏观力学特性以及注塑成型构件结构强度进行了研究。主要工作如下:1.针对注塑成型的玻纤增强复合材料,研究二阶玻纤取向张量与玻纤取向角度之间的连续函数关系,建立了玻纤均质化RVE模型。基于Taguchi正交试验设计方法,利用DIGIMAT软件对玻纤增强复合材料RVE模型进行仿真实验,定量分析玻纤质量分数(A)、玻纤长径比(B)和玻纤取向张量(C)对玻纤增强复合材料力学特性的影响规律。2.考虑玻纤增强复合材料注塑成型过程中的玻纤分层效应,提出了夹芯分层模型并进行铺层设计。基于灰箱理论和反求工程,选取玻纤长径比、表层厚度比和芯层厚度比、表层玻纤取向张量、玻纤取向矢量旋转角四个影响因素,反演预测玻纤增强复合材料PA66(GF50)的正交各向异性弹性常数,并与材料的宏观拉伸弹性模量E33、泊松比u31和泊松比u32的试验结果进行对比验证,相对误差分别为0.92%、1.82%和2.43%。3.研究玻纤增强注塑成型构件在成型过程中的玻纤取向状态,基于广义牛顿流体本构方程,采用ARD-RSC玻纤取向模型,考虑玻纤间相互作用,应用数值模拟方法预测注塑成型构件的玻纤取向分布。基于复合材料细观力学Mean Field均匀化方法,综合运用复合材料细观建模、离散均质化RVE模型场法、注塑成型加工和结构有限元分析技术,构建了玻纤增强注塑成型构件各向异性强度分析方法流程图。4.对玻纤增强注塑成型牵引杆进行各向异性强度仿真分析,结果显示危险位置与实际破坏位置较为吻合。在此基础上对牵引杆进行了结构改进,结果表明杆体中间部分在拉伸载荷下的最大主应力降低了57.18%,在压缩载荷下的最大主应力降低了79.25%。表明玻纤增强注塑成型工程结构件通孔设计不利于提高其承载能力。
[Abstract]:With the rapid development of rail transit industry, glass fiber reinforced composites have been widely used, and injection molding is economic. One of the most effective and widely used techniques. Because of the dispersion of glass fiber orientation in glass fiber reinforced injection molding components, it is necessary to accurately predict and analyze the bearing characteristics and structural strength of glass fiber reinforced injection molding components. The anisotropy of the material caused by the orientation distribution of glass fiber can not be taken into account. In order to influence the mechanical properties of glass fiber reinforced injection molding components, the mass fraction of glass fiber and the interaction between glass fibers are considered in this paper. Based on the mechanical theory of composite materials, the glass fiber homogenization model was established based on the influence of the ratio of length to diameter of glass fiber and the parameters of injection molding. In this paper, the orthotropic macroscopic mechanical properties of glass fiber reinforced composites and the structural strength of injection molding components are studied. The main work is as follows: 1. The continuous function relationship between the second order glass fiber orientation Zhang Liang and the glass fiber orientation angle is studied, and the RVE model of glass fiber homogenization is established, based on the Taguchi orthogonal design method. The RVE model of glass fiber reinforced composites was simulated by DIGIMAT software, and the glass fiber mass fraction was quantitatively analyzed. The effect of glass fiber length to diameter ratio (B) and glass fiber orientation Zhang Liang (C) on the mechanical properties of glass fiber reinforced composites. 2. Consider the glass fiber delamination effect in the injection molding process of glass fiber reinforced composites. Based on grey box theory and reverse engineering, glass fiber length to diameter ratio, surface thickness ratio and core thickness ratio, surface glass fiber orientation Zhang Liang are selected. The orthogonal anisotropic elastic constants of glass fiber reinforced composites PA66 / GF50 were inversely predicted by four factors affecting the rotation angle of glass fiber orientation vector, and the elastic modulus E33 was correlated with the macroscopic tensile modulus of the composites. The experimental results of Poisson's ratio U31 and Poisson's ratio U32 are compared and verified. The relative error is 0.92%, respectively. 1.82% and 2.43. 3. The glass fiber orientation of glass fiber reinforced injection molding components was studied. Based on the generalized Newtonian fluid constitutive equation, the ARD-RSC glass fiber orientation model was adopted. Considering the interaction between glass fibers, a numerical simulation method was used to predict the glass fiber orientation distribution of injection molding components. Based on the Mean Field homogenization method of composite mesomechanics. Comprehensive use of composite mesoscopic modeling, discrete homogeneous RVE model field method, injection molding processing and structural finite element analysis technology. Flow chart of anisotropic strength analysis of glass fiber reinforced injection molding components is constructed. 4. The anisotropic strength of glass fiber reinforced injection molding traction rod is simulated. The results show that the dangerous position is in good agreement with the actual failure position. On this basis, the structure of the traction rod is improved. The results show that the maximum principal stress of the middle part of the bar body is reduced by 57.18% under tensile load. The maximum principal stress under compression load is reduced by 79.25, which indicates that the through hole design of glass fiber reinforced injection molding is not conducive to improving its bearing capacity.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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