Research On Friction Materials Reinforced With Three Natural Fibers And Performances

In connection with the current situation and trends and some of the problems of fiber reinforced friction materials currently exist, this paper choose three natural fibers as a reinforcing fibers friction materials, preparation, mechanical properties and tribological performance testing of friction materials, and the wear mechanism and thermal stress analysis of the friction materials brake coupling process.Preparation and modification treatment of three kinds of natural fibers and preparation of friction materials. Coir and sisal fibers are modified by physical and chemical degumming method of combining, wool fiber using caustic and heat treatment methods; Based on the basic formula, coir, sisal and wool fibers were used straight and twisting of two forms, the fiber content was 3 wt.%, 6 wt.% and 9 wt.%, the use of mixers and three pressing machines and other equipment for the preparation of three kinds of fiber-reinforced friction materials.Friction mechanical properties tests results and analysis of three kinds of natural and non-natural fiber-reinforced friction materials. For hardness index, hardness values that are 18.46 HRR and 17.3 HRR of samples Z3 and Z6 are smaller, than hardness value of sample N is 63.7HRR, hardness values for the remaining samples were above 60 HRR; For density index, sample N has a density value of 2.214g/cm3, the density values of the remaining samples are less than 2.214g/cm3. It can clearly be seen, adding natural fibers can effectively reduce the density of the friction materials, and the same kind and mode of fiber, the more added the fiber content, the smaller the density of the friction material; Indicators for impact strength, impact strength value of the sample N is 1.21 KJ/m2, impact strength added coir and sisal fibers friction materials are larger than the impact strength of the non-natural fiber friction material, while the impact strength values of added wool friction materials are smaller than the impact strength of non-natural fiber friction material.Tribological performance testing and analysis of the wear mechanism of three natural fibers and non-natural fiber-reinforced friction materials. Were analyzed content and temperature of coir, sisal and wool fibers influence on the friction coefficient and wear rate, and, taking into account the friction coefficient, friction stability and wear rate of the three indicators, the use of fuzzy comprehensive evaluation method evaluate the friction and wear properties, and draw optimum formulations that X5, Y2 and Z1, comprehensive evaluation values were 0.814,0.923,0.909. Wear surface morphology analysis sisal fibers(straight, 6wt.%) reinforced friction materials showed the main wear forms have adhesive wear, fatigue wear, abrasive wear and thermal wear. Surface roughness measurement results of samples X1, Y2, Z1, N showed that the larger roughness and maximum roughness average values, the wear rates of the samples are the greater.Thermal stress analysis of the friction coupling process. On the basis of the thermal differential equations establish on the friction material, the use of finite element analysis software ABAQUS6.14 simulates the geometry of thermal stress coupling of sisal fiber(straight, 6wt.%) friction material in the friction process, results show that: Friction material will produce temperature and stress fields that they are mutual influence in the process of braking friction. The stress of the higher part temperature friction material is also the larger.