短纤维橡胶基复合材料结构—性能—应用技术研究

【作者】 张立群；

【导师】 金日光；

【作者基本信息】 北京化工大学 ， 高分子材料， 1995， 博士

【摘要】 本文从结构—性能研究以及应用技术开发两个方面对短纤维／橡胶复合材料(SFRC)进行了全面的深入探讨。 在结构—性能研究部分，本文首次采用有限元计算对SFRC内应力传递和分配规律进行了分析，同时把Cox剪滞法理论引入到SFRC研究中作为其应力传递模型。二者的计算结果表明：Cox剪滞法理论和有限元计算对SFRC内应力传递和分配规律的体现基本上是相同的。并且纤维长径比越大，纤维体积分数越大，纤维模量／基质模量越小，二者的计算结果就越接近。本文认为，用Cox剪滞法来主要反映纤维拉伸应力和界面剪切应力的分布规律是可行的。基于此，本文建立了SFRC中短纤维临界长径比的数学模型，它能够全面反映SFRC结构因素的影响，比其它模型更适合于SFRC。 本文对SFRC的结构参数作了全面的测试和表征。本文提出了一种新的测试SFRC中短纤维取向分布的新方法：首先对SFRC取向胶片进行表面处理，然后用扫描电子显微镜或光学显微镜进行照摄，最后用图像分析仪进行结果处理，结果表明，这一方法是较为成功的。本文提出用粗单丝纤维代替帘线，用SFRC胶料代替纯胶，然后用H抽出试验测定SFRC界面粘合强度。结果表明，在条件选择恰当时，所测值更接近于实际情况。本文的实验观察还表明：SFRC中短纤维排布很复杂，存在着纤维的弯曲、缠绕、挤压等非理想排布情况。对结构参数的数据处理结果表明：用短纤维长度分布指数来评价短纤维长度分布状况是可行的，而用log—normal函数来模拟长度分布曲线的趋势是可以的，但数值精确性不能令人满意；用单因子指数函数来模拟短纤维的取向分布时，其对分布趋势的拟合规律尚可，但仍然存在着数值精确性欠佳的弊病。 基于所建立的应力传递模型，本文提出了SFRC的纵向模量预测方程和纵向强度预测方程，并对SFRC的拉伸过程进行了计算机模拟计算。本文首次在较大纤维用量和较宽的长度范围内考察了SFRC力学性能与结构参数间的关系，同时考察了理论预测值与实验结果的吻合性。结果表明：对Darlington方程用平均长度考虑长度分布，再结合偏轴拉伸方程考虑取向分布，最终的预测结果与SFRC纵向杨氏模量有较好的拟合性。对Halpin—Tsai方程用平均长度考虑长度分布，用取向因子进行失取向的校正，最终的预测结果也与SFRC纵向杨氏模量有较好的拟合性。基于所建立的SFRC纵向强度预测模型和相应的计算机模拟拉伸过程，本文对SFRC的应力应更多还原

【Abstract】 In this paper, intensive research has been carried out on the short fiber/Rubber composite system for both its structure -property and application technique.In the structure-property research portion, finite-element calculation was employed to analysis the stress -transfer and distribution law of SFRC.In the meantime the theory of Cox shear -lag was introduced to SFRC research and used as its model of stress -transfer. The results of both calculation show that: Cox shear-lag theory are fairly similar to finite-element calculation when they were applied to stress -transfer and distribution law of SFRC. More over, the larger the L/D that is the bigger the volume faction of fiber, the smaller the fiber modulus/matrix modulus, the nearer the results of both calculation. This paper regarded that ? it is feasible to use the method of Cox shear -lag to reflect the tensile stress and the distribution law of interface shear stress of fiber . Based on all these, the mathematical model of short fiber’s critical L/D of SFRC was established, It can fully indicate the influence of SFRC structural factor, thus more suitable to SFRC than any other models.In this paper, SFRC’s structural parameters were tested and describe all round. A new method of testing orientation distribution of short fiber in SFRC was out forward : first, surface - treatment process was carried out on the SFRC orientation film, then take photos of it by means of SEM or microscope, finally Image Analyzer was employed to deal with the result. Results show that: This method is rather successful. In this dissertation, cord and SFRC stock were used to take the place of single fiber and pure rubber respectively and then H pull out test was carried out to test the SFRC interface adhesive strength.It can be seen from the result that , under selected suitable condition, the tested value was very close to the practical conditions. What can also be draw from the observation is that the arrangement of short fiber in SFRC is very complicated, non-ideal arrangement such as crooked, zigzag and crunch are all exist in the fiber. Data processing results of structural parameters indicate that; it is feasible to use short length更多还原