بررسی تأثیر فشار و شعاع انحنای سطح تماس بر ضریب اصطکاک در سطح تماس اتصالات تداخلی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده فنی و مهندسی، واحد اسلام آباد غرب، دانشگاه آزاد اسلامی، اسلام ­آباد غرب، کرمانشاه، ایران

2 دانشکده فنی و مهندسی، دانشگاه آزاد اسلامی، کرمانشاه، ایران

چکیده

اتصالات تداخلی به صورت گسترده در صنعت مورد استفاده قرار می‌گیرند. این اتصالات در معرض بارهای استاتیکی و دینامیکی پاسخگوی نیازهای طراحی هستند. اتصالات تداخلی همواره با عیوبی همراه هستند که بر کارکرد آ نها اثر مستقیم دارند. برای نمونه در هر اتصالی سطح تماس اجزا ایده‌آل و استوانه‌ای کامل نیست و انحراف وجود دارد. این پارامترها از این جهت حائز اهمیت هستند که تغییراتشان بر روی کارآیی و استحکام اتصالات تداخلی تأثیر می‌گذارد. از جمله پارامترهای مؤثر بر استحکام اتصالات تداخلی ضریب اصطکاک، زبری، خواص مواد، ابعاد فیزیکی و نامنظمی‌های هندسی سطح‌های در تماس را می‌توان بیان نمود. در این پژوهش با تغییر قطر و مقدار تداخل و در نتیجه آن، فشار در سطح تداخل، اثر این پارامت رها بر استحکام اتصال و ضریب اصطکاک در سطح تداخل مورد بررسی قرار گرفته است. برای استخراج ضریب اصطکاک از ترکیب نتایج تجربی و المان محدود استفاده شد. روش‌های بررسی آماری فاکتوریل مورد استفاده قرار گرفت و اثرات فشار و قطر بر ضریب اصطکاک و استحکام اتصال مورد بررسی قرار گرفت. نتایج حاصل نشان داد که رابطه قطر با ضریب اصطکاک در سطح تداخل اتصالات تداخلی معکوس است و افزایش تداخل و متعاقب آن فشار، باعث افزایش ضریب اصطکاک خواهد شد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation on the Effect of Pressure and Radius of Contact Surface Curvature on the Friction Coefficient in Contact Surfaces of Interference Fit Joints

نویسندگان [English]

  • Kaveh Abbasi 1
  • Hazhir Ehsasi 2
1 Department of Mechanical Engineering, Islamic Azad University, Eslam Abad-E-Gharb, Kermanshah, Iran
2 Department of Mechanical Engineering, Islamic Azad University, Kermanshah, Iran
چکیده [English]

Interference fit joints are widely used to produce tight joints. Interference fit joints could be applied under dynamics and statics design loads, successfully. Interference fit joints are always imperfect and also affected by some parameters which directly affect the operation of these joints. For instance, the contact surface of every manufactured joint part is not a perfect cylinder and always there are some form defects. The variation of these parameters could affect the performance and strength of interference joints, so these parameters should be considered. Some effective parameters on the strength of interference fit joints are friction coefficient, roughness, materials properties, dimensions and geometric irregularities of contact surfaces. In this study, the effect of diameter of shaft and interference value variation on the friction coefficient in contact surface and strength of joints are investigated. Finite element results are interacted with experimental ones to estimate friction coefficients. Also, factorial method, which is a statistical method for design of experiments, is used to analyze the effects of pressure, which is vary by variation of interference, and radius of contact surface curvature on friction coefficient and strength of joints. Results indicate that the friction coefficient changes with diameter of interference surface, inversely and increase of interference and consequently, pressure leads to growth of friction coefficient.

کلیدواژه‌ها [English]

  • Interference Fit Joint
  • Friction Coefficient
  • Interference Value
  • Pressure
  • finite element modeling
[1]  M. Jafari, K. Abbasi, Restoring Scrapped Turbine Bear- ing Supports of GM Turbochargers Through Optimized Press-Fit Interference Bushing, Iranian Journal of Sci- ence and Technology, Transactions of Mechanical En- gineering, 42(1) (2018) 51-56.
[2]  H. Boutoutaou, M. Bouaziz, J. Fontaine, Modeling of interference fits taking form defects of the surfaces in contact into account, Materials & Design, 32(7) (2011) 3692-3701.
[3]  I. Sogalad, H. Ashoka, N.S. Udupa, Influence of cylin- dricity and surface modification on load bearing ability of interference fitted assemblies, Precision Engineer- ing, 36(4) (2012) 629-640.
[4]  H. Boutoutaou, M. Bouaziz, J.-F. Fontaine, Modelling of interference fits with taking into account surfaces roughness with homogenization technique, Internation- al journal of mechanical sciences, 69 (2013) 21-31.
[5]  R.L. Jackson, I. Green, On the modeling of elastic con- tact between rough surfaces, Tribology Transactions, 54(2) (2011) 300-314.
[6]  G. Gallio, G. Marcuccio, E. Bonisoli, S. Tornincasa, D. Pezzini, D. Ugues, M. Lombardi, D. Rovarino, P. Fino, L. Montanaro, Study of the interference contribution on the performance of an adhesive bonded press-fitted cy- lindrical joint, International Journal of Adhesion and Adhesives, 53 (2014) 89-96.
[7]  D. Croccolo, R. Cuppini, N. Vincenzi, Friction Coeffi- cient Definition in Compression‐fit Couplings Apply- ing the DOE Method, Strain, 44(2) (2008) 170-179.
[8]  D. Croccolo, M. De Agostinis, N. Vincenzi, Static and dynamic strength evaluation of interference fit and ad- hesively bonded cylindrical joints, International Journal of Adhesion and Adhesives, 30(5) (2010) 359-366.
[9]  D. Croccolo, M. De Agostinis, N. Vincenzi, Experimen- tal analysis of static and fatigue strength properties in press-fitted and adhesively bonded steel–aluminium components, Journal of Adhesion Science and Technol- ogy, 25(18) (2011) 2521-2538.
[10]  D. Croccolo, M. De Agostinis, P. Mauri, G. Olmi, In- fluence of the engagement ratio on the joint strength of press fitted and adhesively bonded specimens, Interna- tional Journal of Adhesion and Adhesives, 53 (2014) 80-88.
[11] M. Masjedi, M.M. Khonsari, On the effect of surface roughness in point-contact EHL: Formulas for film thickness and asperity load, Tribology International, 82 (2015) 228-244.
[12] M. Stembalski, P. Preś, W. Skoczyński, Determination of the friction coefficient as a function of sliding speed and normal pressure for steel C45 and steel 40HM, Ar- chives of Civil and Mechanical Engineering, 13(4) (2013) 444-448.
[13] Y.S. Kim, M.K. Jain, D.R. Metzger, Determination of pressure-dependent friction coefficient from draw-bend test and its application to cup drawing, International Journal of Machine Tools and Manufacture, 56 (2012) 69-78.
[14] R.C. Bowers, W.A. Zisman, Pressure Effects on the Friction Coefficient of Thin‐Film Solid Lubricants, Journal of Applied Physics, 39(12) (1968) 5385- 5395.
[15] L. Xiao, S. Björklund, B.G. Rosén, The influence of surface roughness and the contact pressure distribution on friction in rolling/sliding contacts, Tribology Inter- national, 40(4) (2007) 694-698.
[16] S. Timoshenko, Strength of Materials, Part II: Ad- vanced theory and problems, Van Nostrand Reinhold, 1958.
[17] S.W. Lee, D.G. Lee, Torque transmission capability of composite–metal interference fit joints, Composite Structures, 78(4) (2007) 584-595.
[18] R. Seifi, K. Abbasi, Friction coefficient estimation in shaft/bush interference using finite element model up- dating, Engineering Failure Analysis, 57 (2015) 310- 322.
[19] R. Seifi, K. Abbasi, M. Asayesh, Effects of Contact Surface Roughness of Interference Shaft/Bush Joints on its Characteristics, Iranian Journal of Science and Technology, Transactions of Mechanical Engineering, 42(3) (2018) 279-292.
[20] R. Seifi, K. Abbasi, Experimental and Numerical In- vestigation on the Effect of form Defects in Contact Surface of Interference Fit Joints on the Strength of Joint, Journal of Mechanical Engineering of Tabriz University, 48(1) (2018) 215-224 (In Persian).