Analysis of Fatigue Cracks of Diesel Engines Cylinder Heads using a Two-Layer Viscoplasticity Model and Considering Viscousity Effects
محورهای موضوعی : فصلنامه شبیه سازی و تحلیل تکنولوژی های نوین در مهندسی مکانیکحجت عاشوری 1 , بابک بهشتی 2 , محمد رضا ابراهیم زاده 3
1 - PhD Student, Department of Agricultural Machinery, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 - Assistant Prof., Department of Agricultural Machinery, Science and Research Branch, Islamic Azad University, Tehran, Iran
3 - Assistant Prof., College of Agriculture, Yadegar - e- Imam Khomeini (Rah), Shahr-e-rey Branch, Islamic Azad University, Tehran, Iran
کلید واژه: Finite Element Analysis, thermo-mechanical fatigue, Cylinder heads, Valves bridge cracks,
چکیده مقاله :
Loading conditions and complex geometry have led the cylinder heads to become the most challenging parts of diesel engines. One of the most important durability problems in diesel engines is due to the cracks valves bridge area. The purpose of this study is a thermo-mechanical analysis of cylinder heads of diesel engines using a two-layer viscoplasticity model. The results of the thermo-mechanical analysis indicate that the maximum temperature and stress exist in the valves bridge. The results of the finite element analysis correspond with the experimental tests, carried out in references, and illustrate the cylinder heads cracked in this region. The results of the thermo-mechanical analysis show that when the engine is running the stress in the region is compressive caused by the thermal loading and combustion pressure. When the engine shuts off the compressive stress turns into the tensile stress because of assembly loads. The valves bridge is under the cyclic tensile and compressive stress and then is under low-cycle fatigue. After several cycles the fatigue cracks will appear in this region. The lifetime of this part can be determined through finite element analysis instead of experimental tests. Viscous strain is more than the plastic strain which is not negligible
سرسیلندر موتور دیزل بعلت بارگذاری و هندسه پیچیده آن یکی از چالش برانگیزترین قطعات موتور است. یکی از مهمترین مسائل دوام موتورهای دیزل ترکهای ایجاد شده در پل بین دریچه ها است. هدف این پژوهش، تحلیل ترمومکانیکی سرسیلندر موتور دیزل با استفاده از الگوی ویسکوپلاستیسیته دو لایه است. نتایج تحلیل ترمومکانیکی نشان داد که ماکزیمم دما و تنش در ناحیه پل بین دو سوپاپ گاز و دود رخ میدهد. نتایج تحلیل المان محدود با آزمونهای تجربی انجام شده در منابع که سرسیلندر در این ناحیه ترک خورده است، مطابقت دارد. نتایج تحلیل ترمومکانیکی نشان داد که تنش در این ناحیه در زمان روشن بودن موتور فشاری است که ناشی از بارگذاری حرارتی و فشار احتراق است. تنش فشاری بعد از خاموش شدن موتور به تنش کششی تبدیل میشود که ناشی از بارهای همبندی است. پل بین دو سوپاپ گاز و دود تحت تنش سیکلی کششی و فشاری و درنتیجه تحت خستگی کمچرخه قرار دارد. بعد از چند سیکل ترکهای خستگی در این ناحیه ایجاد میشود. عمر این ناحیه را میتوان با تحلیلهای المان محدود به جای آزمونهای اعتبارسنجی تعیین نمود. مقدار کرنش ویسکوز از کرنش پلاستیک بیشتر بود و مقدار آن قابل صرفنظر کردن نیست
[1] Azadi M., Mafi A., Roozban M., Moghaddam F., Failure analysis of a cracked gasoline engine cylinder head, Journal of Failure Analysis and Prevention, 12, 2012, pp. 286-294.
[2] Azadi M., Winter G., Farrahi G.H., Eichlseder W., Design of cylinder head and block in international combustion engines based on fatigue strength of materials, 8th International Conference on Internal Combustion Engines and Oil, Tehran, Iran, 2012.
[3] Gocmez T., Pishinger S., A contribution to the understanding of thermo-mechanical fatigue sensitivities in combustion engine cylinder heads, Journal of Automobile Engineering, 225, 2011, pp. 461-477.
[4] Li J., Wang P., Cui X., Li K., Yi R., Gray Cast Iron Cylinder Head Thermal Mechanical Fatigue Analysis, Proceedings of the FISITA 2012 World Automotive CongressLecture Notes in Electrical Engineering, Berlin, Germany, 2013, 189, pp. 243-257.
[5] Metzeger M., Leidenfrost M., Werner E., Riedel H., Seifert T., Lifetime Prediction of EN-GJV 450 Cast Iron Cylinder Heads under Combined Thermo-mechanical and High Fatigue Loading, SAE International Paper No.2014-01-9047,2014.
[6] Su X., Zubeck M., Lasecki J., Engler-Pinto Jr C.C., Tang C., Sehitoglu H., Allison J., Thermal fatigue analysis of cast aluminum cylinder heads, SAE International Paper No.2002-01-0657, 2002.
[7] Thalmair S., Thiele J., Fishersworring-Bunk A., Ehart R., Guillou M., Cylinder heads for high power gasoline engines-thermo-mechanical fatigue life prediction, SAE International Paper No.2006-01-0655, 2006.
[8] Trampert S., Gocmez T., Pisinger S., Thermo-mechanical fatigue life prediction of cylinder head in combustion engines, Journal of Engineering for Gas Turbines and Power, 130, 2008, pp. 1-10.
[9] Zahedi F., Azadi M., Low-cycle fatigue life analysis of magnesium alloy diesel engine cylinder head, 20th Annual International Conference on Mechanical Engineering, Shiraz, Iran, 2012, Paper No. ISME2012-2063.
[10] Xuyang G., Cheng Y., Zhang Z., Thermo-mechanical fatigue life prediction of heavy duty diesel engine cylinder head, ASME International Mechanical Engineering Congress and Exposition, California, U.S.A 2013.
[11] Takahashi T., Sasaki K., Low-cycle fatigue of aluminum alloy cylinder head in consideration of changing metrology microstructure, Journal of Procedia Engineering, 2, 2010, pp. 767-776.
[12] Mirsalim S.M., Chamani H.R., Rezaloo Y., Keshavarz M., Jafarabadi M., Analysis of Cracked Cylinder Head of Diesel Engine due to Fatigue and Improvement its Design, 6th International Conference on Internal Combustion Engines, Tehran, Iran, 2009.
[13] Takahash T.I., Nagayoshi T., Kumano M., Sasaki K., Thermal plastic-elastic creep analysis of engine cylinder head, SAE International Paper No.2002-01-585, 2002.
[14] Farrahi G.H., Ghodrati M., Azadi M., Rezvani Rad M., Stress-strain time-dependent behavior of A356.0 aluminum alloy subject to cyclic thermal and mechanical lading, Journal of Mech Time-Depend Mater, 18, 2014, pp. 475-491.
[15] Thomas J.J., Vergner L., Bignonnet A., Borret S.M., Thermo-mechanical design in the automotive industry, SAE International Paper No.2002-01-0659, 2002.
[16] Thomas J.J., Vergner L., Bignonnet A., Charkaluk E., Thermo-mechanical design in the automotive industry, Journal of Fatigue and Fracture of Engineering Material and Structure, 27, 2004, pp. 887-895.
[17] Remy L., Petit J., Temperature-Fatigue interaction, Elsevier, Paris, France, 2001.
[18] Shojaefard M.H., Ghaffarpour M.R., NourpourA.R., Alizadenia S., Thermo-mechanical Analysis of an Engine Cylinder Head, Journal of Automotive Engineering, 220, 2006, pp.627-636.
[19] Ziehler F., Langmayr F., Jelatancev A., Wieser K., Thermal mechanical fatigue simulation of cast iron cylinder heads, SAE International Paper No.2005-01-0796, 2005.
[20] Challen B., Baranescu R., Diesel Engine Reference Book, 2nd Edition, Butterworth-Heinemann, Oxford, England, 1999.
[21] Chamani H.R., Sattarifar I., Mohammadi Aghdam M., Study of effect combustion gases and cooling thermal boundary conditions on temperature distribution of a heavy diesel engine cylinder head, Journal of engine research, 17, 2009, pp. 71-81.
[22] Koch F., Massan F., Deuster U., Loeprecht M., Marckward H., Low-cycle fatigue of aluminum cylinder heads-Calculation and measurement of stain under fired operation, SAE International Paper No.1999-01-0645, 1999.
[23] Venkateswaran N., Vinobakrishnan R., Balamurugan V., Thermo-mechanical Analysis of the Cylinder Block with the Liner of AFV Diesel Engine, SAE International Paper No.2011-28-0118, 2011.
[24] Ghasemi A., Cylinder Head High/Low Cycle Fatigue CAE Analysis, SAE International Paper No.2012-01-1999, 2012.
[25] Rahman M.M., Arffin A.K., Abdullah S., Noor M.M., Baker R.A., Maleque M.A., Fatigue life prediction of cylinder head for two stroke linear engine using stress-life approach, Journal of Applied Science, 8, 2008, pp. 3316-3327.
[26] Bialas M., Finite element analysis of stress distribution in thermal barrier coating, Journal of surface and coating, 202, 2008, pp. 6002-6010.
[27] Azadi M., Balo M., Farrahi G.H., Mirsalim, S.M., A review of thermal barrier effects on diesel engine performance and components lifetime, International Journal of Automotive Engineering, 3, 2013, pp. 305-317.
[28] Moridi A., Azadi M., Farrahi, G.H., Numerical simulation of thermal barrier coating system under thermo-mechanical lading, Word congress on engineering, London, England, 2011.
[29] Moridi A., Azadi M., Farrahi, G.H., Coating thickness and roughness effect on stress distribution of A356.0 under thermo-mechanical lading, Journal of Procedia Engineering, 10, 2011, pp. 1372-1378.
[30] Moridi A., Azadi M., Farrahi, G.H., Thermo-mechanical stress analysis of thermal barrier coating system considering thickness and roughness effects, Journal of Surface and Coating, 243, 2014, pp. 91-99.
[31] Kichenin J., Dang van K., Boytard K., Finite-element simulation of a new two-dissipative mechanisms model for bulk medium-density polyethylene, Journal of Material Science, 32, 1996, pp. 1653-1661.
[32] Deshpande A., Leen S.B., Hyde T.H., Experimental and numerical characterization of the cyclic thermo-mechanical behavior of a high temperature forming tool alloy, ASME Journal of Manufacturing Science and Engineering, 132, 2010, pp.1-12.
[33] Lemaitre J., Chaboche J., Mechanics of Solid Materials, Cambridge University Press, Cambridge, 1990.
[34] Chaboche J. L., Time-independent constitutive theories for cyclic plasticity. International Journal of Plasticity 2, 2, 1986, pp. 149–188.
[35] Chaboche J. L., A review of some plasticity and viscoplasticity constitutive theories. International Journal of Plasticity 24, 2008, pp. 1642–1693.
[36] Angeloni M., Fatigue life evaluation of A356 aluminium alloy used for engine cylinder head, Ph.D Thesis,University of Sau Palu, Brazil, 2011.
[37] Sun G.Q., Shang D.G., Prediction Of Fatigue Lifetime Under multiracial Cyclic Loading Using Finite Element Analysis, Journal of Material and Design, 31, 2010, pp. 126-133.
[38] ABAQUS/CAE(v6.10-1), User’ s Manual, 2010.
