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1 Design and thermal Analysis of Disc Brake using Ansys Khalanisohil *1, G.V.R.Seshagiri rao*2, Anand kumar pathak*3 *1(Student (M.Tech.), Engineering, BM college of technology, Indore, M.P, India) *2(Associate professor in Mechanical Engineering Department, BM college of technology, Indore) *3(Design Engineer in niest, Indore, M.P, India, Indore,India) Abstract Braking system represents one of the most primary safety critical components in modern vehicles. Brake absorbs the kinetic energy of the rotating parts (Wheels) and the energy is dissipated in the form of heat energy to the surrounding atmosphere. It decelerates or stops the vehicle. When the brake is applied to the disc brake it is subjected to high stress, thus it may suffer structural and wear issues. Hence, for better performance, structural, stress and the thermal analysis are preferred to choose low stress material. Exclusive of the brake system in the vehicle will place a passenger in risky location. Therefore, it is must for all vehicles to have a proper brake system. The objective of this paper is to model the brake with aluminum and gray iron materials and analysis for calculating normal force, shear force and piston force. The standard disc brake two wheeler model using in Ansys and done the Thermal analysis. This is significant to understand the action force and friction force on the disc brake new material, how disc brake works more efficiently which can help to decrease the accidents. Keywords Disc Brake, Thermal Analysis, Ansys Introduction The disc brake is a wheel brake which slows the rotation of the wheel by the friction caused by pushing brake pads against a brake disc with a set of calipers as shown in fig.1.0 The brake disc (or rotor in American English) is usually made of cast iron, but may in some cases be made of composites such as reinforced carbon carbon or ceramic matrix composites. This is connected to the wheel and/or the axle. To stop the wheel, friction material in the form of brake pads, mounted on a device called a brake caliper, is forced mechanically, hydraulically, pneumatically or electromagnetically against both sides of the disc. Friction causes the disc and attached wheel to slow or stop. The brakes convert motion to heat, and if the brakes get too hot, they become less effective, a phenomenon known as brake fade. Discs are made up mainly gray cast iron, so discs are damaged in one of three ways: scarring, cracking, warping or excessive rusting. Service shops will sometimes respond to any disc problem by changing out the discs entirely. This is done mainly where the cost of a new disc may actually be lower than the cost of workers to resurface the original disc. Mechanically this is unnecessary unless the discs have reached manufacturer's minimum recommended thickness, which would make it unsafe to use them, or vane rusting. Severe (ventilated discs only). Most leading vehicle manufacturers recommend brake disc skimming (US: turning) as a solution for lateral run-out, vibration issues and brake noises. Fig 2.0 shows the layout of disc brake. 1

2 validation simulation experiments proved its adequacy. Literature Review Abd Rahim et al. [1] This paper studies the contact pressure distribution of a solid disc brake as a result of structural modifications. Before modifications are simulated, four different models of different degrees of complexity of contact analysis are investigated. It is shown that the contact pressure distributions obtained from these four models are quite different. This suggests that one should be careful in modelling disc brakes in order to obtain correct contact pressure distributions. This work could help design engineers to obtain a more uniform pressure distribution and subsequently satisfy customers needs by making pad life longer. M. Nouby et al.[2] proposes an approach to investigate the influencing factors of the brake pad on the disc brake squeal by integrating finite element simulations with statistical regression techniques. Complex eigenvalue analysis (CEA) has been widely used to predict unstable frequencies in brake systems models. The finite element model is correlated with experimental modal test. The input output relationship between the brake squeal and the brake pad geometries constructed for possible prediction of the squeal using various geometrical configurations of the disc brake. Influences of the various factors, namely; Young s modulus of the back plate, back plate thickness, chamfer, distance between two slots, slot width and angle of the slot are investigated using design of experiments (DOE) technically. A mathematical prediction model has been developed based on the most influencing factors and the Huajiang Ouyang et al. [3] covers two major approaches used in the automotive industry, the complex eigenvalue analysis and the transient analysis. The advantages and limitations of each approach are examined. This review can help analysts to choose right methods and make decisions on new areas of method development. It points out some outstanding issues in modelling and analysis of disc brake squeal and proposes new research topics. It is found that the complex eigenvalue analysis is still the approach favoured by the automotive industry and the transient analysis is gaining increasing popularity. Many investigations of heat flow through ventilated disc brakes are reported in the literature. Michael and Roland [4] discussed the airflow patterns in the disc rotors. Wallis et al. [5] Carried out a numerical study using the software Fluent on disc rotor blades to examine the effects of local heat and mass transfer of the axial gap distances for a single co-rotating disc. The study of the single rotating disc showed that heat and mass transfer coefficients are enhance considerably by decreasing the hub height A ventilated disc is lighter than a solid one, and with additional convective heat transfer occurring on the surface of the vent hole. Thus, the ventilated disc can control its temperature rise and minimize the effects of thermal problems such as the variation of the pad friction coefficient, brake fade and vapor lock [6, 7]. The ventilated disc, however, may increase Judder problems by inducing an uneven temperature field around the disc. Also, the thermal 2

3 capacity of the ventilated disc is less than that of the solid disc, and the temperature of the ventilated disc can rise relatively faster than that of the solid disc during repetitive braking [8]. Therefore, thermal capacity and thermal deformation should be carefully considered when modifying the shape of the ventilated disc. Amol A. Apte and H. Ravi[9] has analyzed finite element prediction of thermal performance of disc brake & stresses in a disc brake system. Validation of brake disc design is carried out through CAE/FEA. The procedure for the prediction of thermal performance of the disc is developed & it correlates with test data available for the recently available design & it applied to the new brake disc design. M.Rama Narasimha Reddy et al.[10] has analyzed structural &thermal analysis of disc brake. In this work they compare the results for stainless steel & carbon steel & result obtained is that both the materials has stress value less than the yield stress, but the thermal gradient of carbon steel is more than stainless steel so carbon steel is better than stainless steel. In this study, a model of the thermal behaviour of a dry contact between the discs of brake pads during the braking phase; the strategy of calculation is based on the software ANSYS 14.5 As a current study of the problem, ANSYS simulations with less assumptions and less program restrictions have been performed for the thermo-mechanical case. A temperature distribution obtained by the transient thermal analysis is used in the calculations of stresses on the disc surface. Design and Calculation of disc brake Disc outer Diameter Disc inner Diameter Disc Thickness Calliper piston diameter Area of master cylinder Coefficient of friction Weight distribution Static rolling radius front tyre Static rolling radius rear tyre Coefficient of friction of road and tyre Brake torque Braking effort Deceleration 190 mm 127mm 5 mm 29.21mm mm % to rear 40% to front 842.6mm mm N-m 100 N 6.86 ms-2 Vehicle speed 60km/hr Stopping distance 9.247m Stopping time 2.32 sec Table 1.0 shows the Dimensions of Disc brake OBJECTIVE The main objective is to design Disc brake using creo software and carry out the finite element analysis (FEA) using ANSYS Thus we obtained the values of shear stress, total deformation, and convective heat transfer coefficient and temperature distribution on disc brake. Fig 2.0 Disc Brake layout 3

4 USING ANSYS CAD MODEL Ansys is one of the useful software for design analysis in mechanical engineering. This software is based on the Finite Element Method (FEM) to simulate the working conditions of your designs and predict their behaviour. FEM requires the solution of large systems of equations. Powered by fast solvers, Ansys makes it possible for designers to quickly check the integrity of their designs and search for the optimum solution. A product development cycle typically includes the Following steps: Build your model in the Pro-Engineer system. simulate the design and find out the results. Fig 3.0 shows the Model of Disc brake which has been done using creo software. MESHED MODEL Fig 4.0 Meshed model of Disc Brake Figure 4 shows the meshed model of disc brake for Thermal analysis.for analysis disc brake was meshed using triangular surface meshes. The model is mashed and analyzed to get the result of contact zone (disc-pad). This is very important because in this zone the temperature rises considerably. CALCULATIONS Mass of vehicle = 225 kg Velocity of vehicle = m/s Kinetic Energy = ½ *M*V 2 = Joules Kinetic energy = Thermal Energy absorbed by brakes Fig 3.0 Cad model of Disc Brake Heat flux = Thermal Energy/ 2 * Area of rubbing surface = W/m 2 Braking Efficiency is 60:40 for front and rear so heat flux= *.6= W/m 2 4

5 Disc brake Material properties Table 2.0 shows the Properties of different materials Name A356-T6 Aluminium Class 30 Grey iron Al/SiC MMC ( 20 % aluminium) Al/SiC MMC ( 30 % aluminium) Young s Modulus Gpa Poisson s ratio Thermal conductivity W/mK Density g/cm3 Specific Heat J/Kg C Table 2.0 shows the Properties of different materials Fig 5 A356-T6 Aluminium Disc brake 5

6 Fig 6.0 Time vs temperature Fig 7.0 Class 30 Grey iron Disc brake 6

7 Fig 8.0 Time vs temperature Fig 9.0 Al/SiC MMC( 20 % aluminium) 7

8 Fig 10.0 Time vs temperature Fig 11.0 Al/SiC MMC ( 30 % aluminium) 8

9 RESULTS AND DISCUSSIONS Fig 12.0 Time vs temperature Simulated results of various disc brake materials are shown in Table 3.0, Fig 5.0 to Fig 12.0 shows the temperature distribution and temperature vs time for various materials. Type of Material Temperature ( 0 C) A356-T6 Aluminium Class 30 Grey iron Al/SiC MMC ( 20 % aluminium) Al/SiC MMC ( 30 % aluminium) CONCLUSIONS

10 CONCLUSIONS Using different disc brake material, calculating the standard disc brake two wheeler model using in Ansys, done the Thermal Analysis calculate the deflection, total heat flux, Frequency and temperature of disc brake model. It has been observed temperature distribution for aluminium and gray iron materials. This is important to understand the action force and friction force on the disc brake new material, which use disc brake works more efficiently, which can help to reduce the accidents. 10. M. Rama Narasimha Reddy, K.Harshavardhan Reddy, N.Balaji Ganesh, Design, Structural and Thermal Analysis & Disc Brake. IJFSET REFERENCES 1. Abd Rahim Abu Baker, Huajiang OuyangPrediction of Disc Brake Contact Pressure Distributions by Finite Element Analysis Jurnal Teknologi 43(A) Dis. 2005: 2136 Universiti Teknologi Malaysia 2.M. Nouby, D. Mathivanan, K. Srinivasan,A combined approach of complex eigenvalue analysis and design of experiments (DOE) to study disc brake squeal International Journal of Engineering, Science and Technology Vol. 1, No. 1, 2009, pp Huajiang Ouyang, Wayne Nack, Yongbin Yuan, Frank Chen,Numerical analysis of automotive disc brake squeal, Int. J. Vehicle Noise and Vibration, Vol. 1, Nos. 3/4, Hudson, M., Ruhl, R., Ventilated brake rotor air flow investigation, SAE Technical Paper , Wallis, L., Leonardi, E., Milton, B., Air flow and heat transfer in ventilated disc brake rotors with diamond and tear-drop pillars, Proceedings of International Symposium on Advances in Computational Heat Transfer, Australia, 2002, pp Choi, B. K., Park, J. H., Kim, M. R., Simulation of the braking condition of vehicle for evaluating thermal performance of disc brake, Proceedings of KSAE Autumn Conference, 2008, pp Jacobsson, H., Aspects of disc brake judder, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 217 (6) (2003) Jung, S. P., Park, T. W., Kim, Y. G., A study on thermal characteristic analysis and shape optimization of a ventilated disc, International Journal of Precision Engineering and Manufacturing 13 (1) (2012) Amol A. Apte and H. Ravi, FE Prediction of Thermal Performance and Stresses in a Disc Brake System, SAE Technical Paper,