Sebuah Kajian Pustaka: JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.4, No. 1, May 2019 ISSN 2541-6332 | e-ISSN 2548-4281 Journal homepage: http://ejournal.umm.ac.id/index.php/JEMMME Munaji | Failure Analysis of Brake Panel on Automotive Braking System 23 Failure Analysis of Brake Panel on Automotive Braking System Munajia, Yoyok Winardia, aFaculty of Engineering, Universitas Muhammadiyah Ponorogo Jl. Budi Utomo No. 10, Ponorogo, Indonesia Telephone/fax : (0352)481124/(0352)461796 e-mail: munaji@umpo.ac.id Abstract This paper presents the results of a failure analysis investigation conducted in the braking component of motorcycle. One of the components is the brake panel. This component has been replaced in the non-authorized dealer. After used within 3 months, the brake panels broken during the braking process. The investigation involves several procedures and testing techniques, including: visual observation, chemical composition testing, fractography and hardness testing. Based on the results of the chemical composition testing, the brake panels are made of aluminum alloy (Al-Si) series 4xxx. Fractography was performed in scanning electron microscopy (SEM) and optical microscopy (OM). Vickers hardness machine is used to test the hardness. The result of the observations indicate porosity along the fracture area. The result of the hardness testing shows that the distribution of hardness in different zones is very uniform. Based on the overall analysis, the failure of the brake panel is caused by stress concentration due to the porosity in the solid solutions. The emergence of porosity was suspected an error during the casting process. Keywords: brake panel; failure analysis; stress concentration 1. INTRODUCTION For safety riding, the brake is a very important component. When a vehicle was running, it takes force to stop. The main factor is a friction force from the brake. When the friction force given on the rotated wheels, the wheel will slow down and finally stop (1). The factor in determining deceleration of the vehicle include the weight of a vehicle, coefficient of friction, pressure distribution on the surface area of braking, and the braking force (2). In order to fulfil this criteria, braking system should be following requirement (3): The brake must be strong enough to decrease vehicle acceleration, the braking system must have simple operational for the driver, and the braking system have to wear resistant properties and good heat resistant properties. Generally, the type of vehicle brake system is drum brake and disc brake. Mechanical and hydraulic used as the operating system. In recent years, drum brake is widely used on small capacity of motorcycles. The main factor is cheap and simple. Brake which utilizes friction between the material generate heat. It can produce residual stress which is reducing the strength of materials (4). Impact loads and larger braking force can also caused failure of the braking components (5). Furthermore, the friction of kinetic force from wheel vehicles is producing the heat. Hence, overheating on braking components can also be a fracture initiation. http://ejournal.umm.ac.id/index.php/JEMMME mailto:munaji@umpo.ac.id JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.4, No. 1, May 2019 Munaji | Failure Analysis of Brake Panel on Automotive Braking System 24 A dispersion casting process is used in brake panel manufacturing. The brake panel slurry is quickly poured to the sand molding and then machined to desired sizes. The most defect of brake panel manufacturing are the occurrence of shrinkage and blowholes at casting process and sand inclusion after machining process (6). Brake panel is a braking component with double work. Besides as mounting of brake shoe, it also serves to hold all forces during the braking process. Commonly brake panel is made from aluminum alloys. In this case, when the motorcycle through over holes on the road and the rider braking suddenly, the brake panel was fracture. So the braking component not function as usual. To determine the cause of the failure is needed physical and mechanical research. In this study, the cause of failure was analyzed. To obtain the information, some of the methods are used. Description of the failure, metallurgical analysis, and mechanical properties will be discussed. 2. METHOD Methods used to determine the occurrence of failured component are macro and micro observation, chemical composition, and testing of mechanical properties (7). Failure analysis of braking panel system of motorcycle are presented. Figure 1 shows the brake system component of a motorcycle. Brake panel/backplate is a failured component. This component has been repaired. After used in 3 months, the brake panel is fractured during braking process. From the result of the observation using digital camera, the obtained shape and fracture location as shown in Figure 2. Figure 1. Braking system Figure 2. Broken component JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.4, No. 1, May 2019 Munaji | Failure Analysis of Brake Panel on Automotive Braking System 25 3. RESULTS AND DISCUSSION 3.1 Material composition Generally, aluminium alloys are used as automotive parts. They have good mechanical properties and corrosion resistant, from the chemical test a aluminium alloy with Si alloying less than 13% is Aluminium alloy 4XXX series (8). The chemical composition of aluminium alloys series 4XXX (Al-Si) used as brake panel are listed in Table 1. Table 1. Chemical composition of brake panel Element Composition (%) Al 83,89 Si 11,4 Zn 2,76 Fe 1,20 Mn 0,408 Cu 0,120 Cr 0,0837 Sn 0,0510 Ti 0,0108 Pb < 0,030 Ca 0,0042 V < 0,0100 3.2 Fractrographs The results of the observation on the fracture surface are shown in Figure 3. and Figure 4. Scanning electron microscopy (SEM) and optical microscope (OM) methods are used to visualize the fracture surface. Based on the result of the observations in the figure 3.a, it can be seen the initial cracks on the surface of test specimen. The crack propagates with big dimensions. These cracks propagate continues in line with the change of the force. Moreover, observations along fracture lines indicate porosity, as shown in Figure 3.a and 3.b. In Figure 3.a, the dimension of blowholes are large. On the other hand the observation result shows that void surface is more smooth, a smoother surface is indicated cause gas trapped in the casting process (9). As the consequence of these void, stress amplification increase at that section (10). It can increase fracture probability at void section. Figure 3. (a) SEM image of void. (b) Oxide inclusions void a b JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.4, No. 1, May 2019 Munaji | Failure Analysis of Brake Panel on Automotive Braking System 26 Figure 4. (a) Crack propagation. (b) Dimension of void Porosity, occur in almost all aluminium alloy castings, can decrease their mechanical properties (11) and increase fatigue live (12). The occurrence of porosity is due to two main aspects, (i) the shrinkage of casting slurry during the solidification; (ii) the solubility of gasses (13), (14). Hydrogen is the main gas of porosity agent in aluminium casting as hydrogen is highly soluble gas (15), (16). One of the objectives of good casting product is avoiding porosity in a casting product. This can be achieved by melt degassing. In aluminium cast slurry, the amount of hydrogen can reach 0.3–0.5 cm3/100 g, while the industrial standard requires the concentration of hydrogen before casting close to 0.1 cm3/100 g (17). The control of hydrogen is of major concern in foundries, to control porosity result from trapped gas, several methods are used, either separately or in combination, such as blowing nitrogen or argon into the melt (16), (18), (19), re-melting (20), and rotating impeler degassing (21). Observations on the fracture surface shows that the fracture occurred between grain boundaries. Fracture surface is rough and brittle with a dark color may indicate that fracture is intergranular fracture types (10). 3.3 Hardness Testing In this study, vickers hardness testing is used to determine the distribution of hardness value areas near the fault and areas far away from the fracture. Testing is done according to the standard ASTM E92 (22). Indentation performed at 5 times with a load of 100 gf for 10 seconds. The test results obtained hardness values are not much different. This means that the distribution of hardness in both these areas is very uniform. The average value of hardness fracture area is 110.6 HVN. This value is relatively higher when compared to areas far away from the fault in value by 109.46 HVN. 4. CONCLUSIONS The cause of the failure on motorcycle brake panel has been investigated. Based on the results of the investigation on the brake panel, the failure is caused by stress concentration. Stress concentration is caused by void. The emergence of the void caused by the inability of the fluid of aluminium alloy to form a solid during the casting process. To reduce the occurrence of void in the component, nitrogen gasses can be sprayed during the casting process. So that the trapped oxygen can come out of the casting liquid and minimize the voids, then the strength of the component can be maximized. The casting process can change from disperssion casting to squeeze casting to repair imperfection of casting product. a b initial cracks JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.4, No. 1, May 2019 Munaji | Failure Analysis of Brake Panel on Automotive Braking System 27 REFERENCES 1. O. P. Singh, S. Mohan, K. V. Mangaraju, M. Jayamathy, and R. Babu, 2010, “Thermal seizures in automotive drum brakes,” Eng. Fail. Anal., vol. 17, no. 5, pp. 1155–1172. 2. C. Sharma and M. Dhingra,2015, “Braking Systems in Railway Vehicles”, Inter. Jour. Eng. Res. Tech., vol. 4, pp. 206–211. 3. A. Kumar and R. Sabarish, 2014, “Structural and Thermal Analysis of Brake Drum,” Middle-East Jour.Sci.Res., vol. 20, no. 8, pp. 1012–1016. 4. M. Kushal and S. Sharma, 2015, “Optimization of Design of Brake Drum of Two Wheeler through Approach of Reverse Engineering by Using Ansys Software,” IOSR. Jour. Mech. Civ. Eng., vol. 12, no. 4, pp. 70–75. 5. S. D. Oduro, 2012, “Brake Failure and its Effect on Road Traffic Accident in Kumasi,” Inter. Jour. Sci. Tech., vol. 1, no. 9, pp. 448–453. 6. T. Daems, S. Karinka, B. S. A, and E. Versonnen, 2016, “Manufacturing Process Defects of Automotive Brake Drums and Implementation of Poka- Yoke – A Case Study,” Inter. Jour. Inov. Res. Sci. Eng. Tech., pp. 893–903. 7. S. Nishida.1992. “Failure Analysis in Engineering Applications.” Oxford: Butterworth- Heinemann Ltd. 8. M. Warmuzek. 2004. Aluminum-silicon casting alloys: an atlas of microfractographs. USA:ASM International. 9. J. Campbell. 2011. "Complete Casting Handbook Metal Casting Processes , and Design”. Oxford:Elsevier Ltd. 10. W. D. Callister, 1991, “Materials science and engineering: An introduction (2nd edition),” Mater. Des., vol. 12, no. 1, p. 59. 11. D. Dispinar and J. Campbell, 2011, “Porosity , hydrogen and bifilm content in Al alloy castings,” Mater. Sci Eng. A, vol. 528, no. 10–11, pp. 3860–3865. 12. I. Serrano-munoz, J. Buffiere, C. Verdu, Y. Gaillard, P. Mu, and Y. Nadot, 2016, “Influence of surface and internal casting defects on the fatigue behaviour of A357-T6 cast aluminium alloy,” Inter. Jour. Fat., vol. 82, pp. 361–370. 13. Y. Ren, W. Ma, K. Wei, W. Yu, and Y. Dai, 2014, “Degassing of aluminum alloys via the electromagnetic directional solidifi cation,” Vaccum, vol. 109, pp. 82–85. 14. H. Puga, J. Barbosa, N. Q. Tuan, and F. Silva, 2014, “Effect of ultrasonic degassing on performance of Al-based components,” Trans. Nonferrous Met. Soc. China, vol. 24, no. 11, pp. 3459–3464. 15. R. Haghayeghi, H. Bahai, and P. Kapranos, 2012, “Effect of ultrasonic argon degassing on dissolved hydrogen in aluminium alloy,” Mater. Lett., vol. 82, pp. 230– 232. 16. R. Haghayeghi and P. Kapranos,2014, “The effect of processing parameters on ultrasonic degassing efficiency,” Mater. Lett., vol. 116, pp. 399–401. 17. D. G. Eskin, K. Al-helal, and I. Tzanakis, 2015, “Application of a plate sonotrode to ultrasonic degassing of aluminum melt : Acoustic measurements and feasibility study,” J. Mater. Process. Tech., vol. 222, pp. 148–154. 18. D. Dispinar, S. Akhtar, A. Nordmark, M. Di Sabatino, and L. Arnberg, 2010, “Degassing, hydrogen and porosity phenomena in A356,” Mater. Sci. Eng. A, vol. 527, no. 16–17, pp. 3719–3725. 19. X. Liu, Z. Zhang, W. Hu, Q. Le, L. Bao, J. Cui, and J. Jiang, 2015, “Ultrasonics Sonochemistry Study on hydrogen removal of AZ91 alloys using ultrasonic argon degassing process,” Ultrason. - Sonochemistry, vol. 26, pp. 73–80. 20. L. Zhao, Y. Pan, H. Liao, and Q. Wang, 2012, “Degassing of aluminum alloys during re-melting,” Mater. Lett., vol. 66, no. 1, pp. 328–331. https://www.researchgate.net/publication/245161868_Thermal_seizures_in_automotive_drum_brakes https://www.researchgate.net/publication/245161868_Thermal_seizures_in_automotive_drum_brakes https://www.researchgate.net/publication/245161868_Thermal_seizures_in_automotive_drum_brakes https://www.researchgate.net/publication/270898470_Braking_Systems_in_Railway_Vehicles https://www.researchgate.net/publication/270898470_Braking_Systems_in_Railway_Vehicles https://www.researchgate.net/publication/290165550_Structural_and_thermal_analysis_of_brake_drum https://www.researchgate.net/publication/290165550_Structural_and_thermal_analysis_of_brake_drum http://www.iosrjournals.org/iosr-jmce/papers/vol12-issue4/Version-4/K012447075.pdf http://www.iosrjournals.org/iosr-jmce/papers/vol12-issue4/Version-4/K012447075.pdf http://www.iosrjournals.org/iosr-jmce/papers/vol12-issue4/Version-4/K012447075.pdf https://www.researchgate.net/publication/279843241_Brake_Failure_and_its_Effect_on_Road_Traffic_Accident_in_Kumasi_Metropolis_Ghana https://www.researchgate.net/publication/279843241_Brake_Failure_and_its_Effect_on_Road_Traffic_Accident_in_Kumasi_Metropolis_Ghana http://www.ijirset.com/upload/2016/icete/mech/24_148_ICETE16_MCH_PID238.pdf http://www.ijirset.com/upload/2016/icete/mech/24_148_ICETE16_MCH_PID238.pdf http://www.ijirset.com/upload/2016/icete/mech/24_148_ICETE16_MCH_PID238.pdf https://www.elsevier.com/books/failure-analysis-in-engineering-applications/nishida/978-0-7506-1065-0 https://www.elsevier.com/books/failure-analysis-in-engineering-applications/nishida/978-0-7506-1065-0 https://www.asminternational.org/technical-books/-/journal_content/56/10192/06993G/PUBLICATION https://www.asminternational.org/technical-books/-/journal_content/56/10192/06993G/PUBLICATION https://www.sciencedirect.com/book/9780444635099/complete-casting-handbook https://www.sciencedirect.com/book/9780444635099/complete-casting-handbook https://onlinelibrary.wiley.com/doi/abs/10.1002/pi.4990300228 https://onlinelibrary.wiley.com/doi/abs/10.1002/pi.4990300228 https://www.researchgate.net/publication/251608573_Porosity_hydrogen_and_bifilm_content_in_Al_alloy_castings https://www.researchgate.net/publication/251608573_Porosity_hydrogen_and_bifilm_content_in_Al_alloy_castings https://www.researchgate.net/publication/281132226_Influence_of_surface_an_internal_casting_defects_on_the_fatigue_behaviour_of_A357-T6_cast_aluminium_alloy https://www.researchgate.net/publication/281132226_Influence_of_surface_an_internal_casting_defects_on_the_fatigue_behaviour_of_A357-T6_cast_aluminium_alloy https://www.researchgate.net/publication/281132226_Influence_of_surface_an_internal_casting_defects_on_the_fatigue_behaviour_of_A357-T6_cast_aluminium_alloy https://www.sciencedirect.com/science/article/abs/pii/S0042207X1400222X https://www.sciencedirect.com/science/article/abs/pii/S0042207X1400222X https://www.sciencedirect.com/science/article/abs/pii/S1003632614634890 https://www.sciencedirect.com/science/article/abs/pii/S1003632614634890 https://www.sciencedirect.com/science/article/abs/pii/S1003632614634890 https://www.researchgate.net/publication/257009806_Effect_of_ultrasonic_argon_degassing_on_dissolved_hydrogen_in_aluminium_alloy https://www.researchgate.net/publication/257009806_Effect_of_ultrasonic_argon_degassing_on_dissolved_hydrogen_in_aluminium_alloy https://www.researchgate.net/publication/257009806_Effect_of_ultrasonic_argon_degassing_on_dissolved_hydrogen_in_aluminium_alloy https://www.researchgate.net/publication/258908716_The_effect_of_processing_parameters_on_Ultrasonic_degassing_efficiency https://www.researchgate.net/publication/258908716_The_effect_of_processing_parameters_on_Ultrasonic_degassing_efficiency https://www.sciencedirect.com/science/article/pii/S0924013615000989 https://www.sciencedirect.com/science/article/pii/S0924013615000989 https://www.sciencedirect.com/science/article/pii/S0924013615000989 248474688_Degassing_hydrogen_and_porosity_phenomena_in_A356 248474688_Degassing_hydrogen_and_porosity_phenomena_in_A356 248474688_Degassing_hydrogen_and_porosity_phenomena_in_A356 https://www.researchgate.net/publication/272075805_Study_on_hydrogen_removal_of_AZ91_alloys_using_ultrasonic_argon_degassing_process https://www.researchgate.net/publication/272075805_Study_on_hydrogen_removal_of_AZ91_alloys_using_ultrasonic_argon_degassing_process https://www.researchgate.net/publication/272075805_Study_on_hydrogen_removal_of_AZ91_alloys_using_ultrasonic_argon_degassing_process https://www.researchgate.net/publication/257008792_Degassing_of_aluminum_alloys_during_re-melting https://www.researchgate.net/publication/257008792_Degassing_of_aluminum_alloys_during_re-melting JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol.4, No. 1, May 2019 Munaji | Failure Analysis of Brake Panel on Automotive Braking System 28 21. H. Ni, B. Sun, H. Jiang, and W. Ding, 2003, “Effects of rotating impeller degassing on microstructure and mechanical properties of the A356 scraps,” vol. 352, pp. 294–299. 22. ASTM E92. 2004. “Standard Test Method for Vickers Hardness of Metallic Materials,” PA:ASTM International. https://www.sciencedirect.com/science/article/abs/pii/S0921509302009000 https://www.sciencedirect.com/science/article/abs/pii/S0921509302009000 https://www.astm.org/Standards/E92.htm https://www.astm.org/Standards/E92.htm