Clutch is used in automobiles with manual transmission systems, washing machines, and many rotating tools. The clutch is used to transmit power and motion. It transmits the rotation movement from a driving shaft, connected to a power source (combust engine or motor) to a driven shaft. In automobiles, clutches are designed to transmit the torque and motion from the flywheel connected to the engine, to the gearbox while maintaining the same velocity, but allowing connection and disconnection between those two parts without the need of stopping the power source (engine). It transmits the motion in automobiles by friction contact. The friction disc of the clutch will be pressurized by springs (mostly diaphragm springs) towards the flywheel, the friction lining will connect to the flywheel and start to rotate with the flywheel, transmitting the motion and torque. Therefore, frictional materials in clutches are being under focus in several research to develop new materials or studying the utility of existing ones to achieve the highest efficiency in transmission of power and motion, while maintaining long working life. The friction lining materials should have beside high friction coefficient, withstanding high temperatures and wear resistance other essential properties such, developing friction force between the lining surface and flywheel, the ability to hold and transmit the load, keeping between surfaces pressure low as possible. Adding to that the material should be able to dissipate and withstand the heat generated from the friction [1]. Many materials have been used as friction lining in clutches. But the most common ones are E-glass epoxy with a competitively low cost. The type of glass fiber is E-class, which is famous for its high quality, it has high strength and even high chemical resistance, but the low modulus of elasticity and the high density considered as a disadvantage because they result in weight increase [2]. Aluminum matrix composites (AMCs), especially Aluminum matrix composite enforced by silicon carbide, with high strength to weight ratio. AMCs reinforced by SiC have a lower coefficient of thermal expansion and higher elasticity modulus than the unenforced aluminum matrix alloy [2]. As the improvement in the reinforced cause of the Sic partials in the material resulting in higher hardness. Artificial Functionally graded materials (FGMs) are only imitating the ones found in nature, such as bones and Mollusk shells. Nevertheless, there are many types of functionally graded materials, many of them share the concept of changing from one material to another material gradually, mostly from metal to ceramic, and to simplify analysis the change is dependent on one direction. The property of the material changes in this direction, we can say the FGMs properties are different in different locations. A new sector of research is concentrating now on functionally graded metal matrix composites (FGMMCs). Essentially, producing metal matrix composites employing means of functionally graded materials, to enhance the properties of materials to be used in components used in multifunction and various conditions with a multiphasic nature. FGMs are produced in many ways, they can be processed by powder stacking (by normal gravity, under pressure-induced flow, or under centrifugal forces), vapor depositing, centrifugal casting, or by solid freeform fabrication [3]. Many pieces of research have been done in the usage of Aluminum matrix composites as friction material of the clutch. S. Dhanasekaran, S. Sunilraj, G. Ramya, and S. Ravishankar in their work [4], found that if aluminum matrix composites are processed by stir casting specifically will result in an arise in three properties tensile, yield strengths and hardness by 16%, 50% and 16% respectively when 20% of the volume is Silicone carbide for reinforcement. R. Gomes et al, found when the Aluminum matrix composite reinforced by 20% silicon carbide produced by functional graded material methods, specifically by centrifugal casting, the wear coefficient is increased to reach \({(10}^{-6}{mm}^{3}/N*m\)), meaning higher wear resistance compared to the homogenous Aluminum matrix composite reinforced by 20% silicon carbide, and friction coefficient of 0.50 when examined against cast iron pin disk[5]. Other research went further studying the effects of the size and percentages of the Silicon Carbide effects just like I.M. El-Galy et al, resulting in many findings, one of them the hardness will increase when using smaller particles. The tensile strength will increase linearly with the increase of the silicon particles until reaching 10% [6]. Considering FGM, M. Siva Suryaa and G. Prasanthib [7], manufactured AL-SiC as functionally graded material by powder metallurgy method, then examined four specimens using a Microscope. The specimens have three layers including different proportions of silicon carbide in aluminum to reach the optimum combination, they found that having 10% SiC can be successfully manufactured. And failure occurs when more than 15% of SiC due to the weakness of the bond between particles of aluminum. In their work G. Shanthi and S. Praveen Kumar [8], they conducted a structural and thermal analysis using finite element represented in ANSYS for multi-clutch plate made of different material to decide which is the best of them, they found that SFBU material has the best characteristics as clutch friction material amount cork, copper, SF100 and SFBU. Ayush Srivastava et al, [9] also, carried out static and dynamic analysis for clutch made off different materials, the traditional cast iron, carbon fiber reinforced polymer, glass fiber reinforced polymer, Boron epoxy, and HT Graphite. They concluded that HT Graphite has the best features to work as friction lining for dry clutch plate, as the weight is less than cast iron clutch while giving approximately the same stresses with higher thermal conductivity. Jairo Aparecido Martins and Estaner Claro Romão [10] examined clutch discs with different materials and geometries statically and dynamically. Cast Iron as reference material while aluminum is under study materials. The difference between geometries is having rips (Disc with rips) or flat discs. They found that aluminum showed better results in static analysis but in dynamics a premature failure due to fatigue occurred, knowing the fatigue is the evaluation criteria of their work. The difference in geometries had no big effect regarding overcoming stresses. Considering only free vibration analysis N. A. Barve and M. S. Kirkire [11], conducted a design and analysis of single-plate clutch with finite element method using Pro-e software and ANSYS comparing it to giving model to result, the two models are approximately having the same natural frequencies. B. Sreevani and M. Murali Mohan [12], also carried out research studying single plate clutch static and dynamic oriented study, for clutches with different materials E-Glass Epoxy, Aluminum Metal Matrix Composite, Aluminum alloys 7075 and Cast-Iron considering stresses and deformations ending up that e-glass plate clutch is better considering the lower weight and acceptable high strength. The same results have been proofed by Seyoum Kebede and Hailemariam Nigus Hailu [13] when they modeled and analyzed multi-plate clutches used in twin-clutch transmission systems. Using finite element method and comparing the performance of different materials as friction linins, Aluminum alloy 6061, Gray Cast Iron, and E-glass epoxy. The last material achieved lower weight, the lowest deformation for its working condition, and acceptable wear resistance. Anosh Ali et al [14], has examined the thermal behavior of clutch plate made of various materials using mathematical and numerical method (mainly finite element). Materials examined were Asbestos, Carbon-Carbon Composite, S2-glass fiber, and Aluminum metal matrix composite. They found that Aluminum metal matrix composite showed better thermal behavior when used as friction materials in dry clutch then longer life of the part can be obtained.
In this research work, different friction materials E-glass epoxy, Aluminum Matrix composite (20% Sic) reinforced, and Functionally graded Aluminum matrix composite (with Silicon carbide) are analyzed as a friction lining of single clutch plate working in usual automobiles conditions regarding Static, Dynamic, Wear, and theoretical Thermal behaviors using finite element method by ANSYS software. To give a comparison result of the possibility of using FGAMCs in friction clutches.
Figure (1) shows a 3d model of manual transmission automobiles clutch set followed by a scheme in figure (2) showing clutch set parts and its connections to the rest of automobile parts.