三种天然纤维增强摩擦材料及其性能研究

发布时间：2019-03-08 09:50

【摘要】：针对目前摩擦材料的现状和发展趋势以及增强纤维存在的一些问题,本论文选用三种天然纤维作为摩擦材料的增强纤维,进行摩擦材料的制备、力学性能及摩擦磨损性能测试,并对磨损机理、摩擦材料制动过程进行热应力耦合分析。三种天然纤维的制备、改性处理及摩擦材料的制备。对于椰壳纤维及剑麻纤维均采用物理改性和化学脱胶相结合的方法,对于羊毛纤维采用碱洗及热处理的方法;在基础配方基础上,椰壳纤维、剑麻纤维及羊毛纤维分别采用平直和加捻两种形式,纤维含量分别为3wt.%、6wt.%及9wt.%,利用混料机及热压机等设备进行三种纤维增强摩擦材料的制备。三种天然纤维及无天然纤维增强摩擦材料力学性能测试结果及分析。对于硬度指标,试样N的硬度值为63.7HRR,试样Z3和Z6的硬度值偏小,即分别为18.46HRR和17.3HRR,其余试样的硬度值均在60HRR以上;对于密度指标,试样N的密度为2.214g/cm3,其余试样的密度值均小于2.214g/cm3,可见,加入天然纤维可有效降低摩擦材料的密度,且同种纤维方式,加入的纤维含量越多,摩擦材料的密度越小;对于冲击强度指标,试样N的冲击强度为1.21KJ/m2,加入椰壳纤维和剑麻纤维的摩擦材料的冲击强度均大于未加入天然纤维的摩擦材料,而加入羊毛纤维的摩擦材料冲击强度均小于未加入天然纤维的摩擦材料。三种天然纤维及无天然纤维增强摩擦材料摩擦磨损性能测试及磨损机理分析。分别分析了椰壳纤维、剑麻纤维及羊毛纤维的含量及温度对摩擦因数及磨损率的影响规律,而且,兼顾摩擦因数、摩擦稳定性及磨损率三个指标,采用模糊综合评价法对摩擦磨损性能进行评价,并得出较优配方,即X5、Y2和Z1,综合评价值分别为0.814、0.923、0.909。对剑麻纤维(平直、6wt.%)增强摩擦材料磨损表面形貌分析表明,粘着磨损、疲劳磨损、磨粒磨损及热磨损是其主要磨损形式。试样X1、Y2、Z1、N磨损表面粗糙度的测量结果表明,粗糙度平均值和粗糙度极大值越大,试样的磨损率就越大。摩擦过程中热应力耦合分析。在建立摩擦材料的导热微分方程基础上,运用有限元分析软件ABAQUS6.14对剑麻纤维(平直、6wt.%)增强摩擦材料在摩擦过程中的热应力耦合进行几何模拟,结果表明:摩擦材料在制动摩擦过程中会产生温度场和应力场,温度场与应力场相互影响,摩擦材料温度高的部分应力也大。
[Abstract]:In view of the present situation and development trend of friction materials and some problems existing in reinforced fibers, three kinds of natural fibers are selected as reinforcing fibers of friction materials in this paper, and the preparation, mechanical properties and friction and wear properties of friction materials are tested. The thermal stress coupling analysis of wear mechanism and braking process of friction material is carried out. Preparation of three kinds of natural fibers, modification and preparation of friction materials. For coconut shell fiber and sisal fiber, physical modification and chemical degumming were used, and alkali washing and heat treatment were used for wool fiber. On the basis of the basic formula, coconut shell fiber, sisal fiber and wool fiber are straight and twisted respectively. The fiber content is 3wt.%, 6wt.% and 9wt%, respectively. Three kinds of fiber reinforced friction materials were prepared by mixing machine and hot press. Test results and analysis of mechanical properties of three kinds of natural fiber and non-natural fiber reinforced friction materials. For hardness index, the hardness value of sample N is 63.7HRR, the hardness value of sample Z3 and Z6 is smaller, that is, 18.46HRR and 17.3HRR, respectively. The hardness values of other samples are above 60HRR. For the density index, the density of sample N is 2.214 g / cm ~ 3, and the density value of other samples is less than 2.214 g / cm ~ 3. It can be seen that adding natural fiber can effectively reduce the density of friction material, and the more the fiber content is, the more the fiber content is added in the same fiber mode. The smaller the density of friction material; For the impact strength index, the impact strength of sample N is 1.21 KJ / m _ 2. The impact strength of friction material with coconut shell fiber and sisal fiber is higher than that without natural fiber, and the impact strength of the friction material with coconut shell fiber and sisal fiber is higher than that without natural fiber. The impact strength of the friction material added wool fiber is lower than that of the friction material without natural fiber. Friction and wear properties test and wear mechanism analysis of three kinds of natural fiber and non-natural fiber reinforced friction materials. The effects of the content and temperature of coconut shell fiber, sisal fiber and wool fiber on friction coefficient and wear rate were analyzed, and three indexes, such as friction coefficient, friction stability and wear rate, were considered. The fuzzy comprehensive evaluation method was used to evaluate the friction and wear properties, and the optimum formula was obtained, that is, X5, Y2 and Z1. The comprehensive evaluation values were 0.814, 0.923 and 0.909, respectively. The wear surface morphology of sisal fiber (straight, 6wt.%) reinforced friction material shows that adhesion wear, fatigue wear, abrasive wear and thermal wear are the main wear forms. The measurement results of surface roughness of X _ 1, Y _ 2, Z _ 1 and N show that the greater the average roughness and the maximum roughness, the greater the wear rate of the specimen. Thermal stress coupling analysis in friction process. On the basis of establishing the differential equation of heat conduction of friction materials, the thermal stress coupling of sisal fiber (straight, 6wt.%) reinforced friction materials during friction is simulated by finite element analysis software ABAQUS6.14. The results show that the temperature field and stress field will occur in the process of braking friction, and the temperature field and stress field will interact with each other, and the partial stress of high temperature of friction material will also be large.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB39

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