Comprehensive Analysis Of Interference Fit And Its Attributes

Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsComprehensive Analysis of Interference Fit andits AttributesM. A. AdhitheyanA. AnanthDepartment of Mechanical EngineeringSaranathan College of EngineeringTiruchirappalli-12Department of Mechanical EngineeringSaranathan College of EngineeringTiruchirappalli-12S. Ajith KumarB. DeepanrajDepartment of Mechanical EngineeringSaranathan College of EngineeringTiruchirappalli-12Department of Mechanical EngineeringSaranathan College of EngineeringTiruchirappalli-12Mr. A. SaravananDepartment of Mechanical EngineeringSaranathan College of EngineeringTiruchirappalli-12Abstract - This paper examines about the stress and strainresults for standard interference values to overcome thedifficulties in the selection of suitable interference values forshaft part and to reduce the welding application byinterference fit method. Work is carried out analytically andexperimentally in both soft and hardened type materials.The interference values and dimensions are correlated usingmini-tab software. FEA simulation is carried out usingANSYS17.2 software. After completion of modeling andanalytical work,the obtained stress and strain results wereanalyzed with respect to dimensions of the shaft and holeparts and interference values. Experimental work is carriedwith various material, machining, assembly processes to getthe fitment. Obtained fit is viewed with scanning electronmicroscope to get the fusion area in mating location.Keywords: Fits, Interference Fit, FEA Analysis, Stress andStrain.I.used for bearing-shaft assembly or bearing-housingassembly. The tightness of fit is controlled by amount ofinterference; the allowance. Formulas exist to computeallowance, which will provide various strength of fitssuch as loose fit, light interference fit and interference fit.Press fit is achieved with pressure that can press the partstogether with very large amount of force. The pressure isgenerally hydraulic operated. The amount of forceapplied in hydraulic presses may be anything from a fewpounds for the tiniest parts to hundreds of tons for thelargest parts. Often the shaft and holes are chamfered.The chamfer forms a guide for the pressing movement,helping to distribute the force evenly around thecircumference of the hole, to allow the compression tooccur gradually instead of all at once, thus helping thepressing operation to be smoother.INTRODUCTIONII.In engineering terms, the "fit" is the clearance betweentwo mating parts, and the size of this clearancedetermines whether the parts can move independentlyfrom each other, or are temporarily or even permanentlyjoined. Fits are of three types which are Clearance Fit,Transition Fit, and Interference Fit. Clearance Fit: Thehole is larger than the shaft, enabling the two parts toslide or rotate when assembled. Transition Fit: The holeis fractionally smaller than the shaft and mild force isrequired to assemble / disassemble. Interference Fit: Thehole is smaller than the shaft and high force or heat isrequired to assemble / disassemble. From the above fits,interference fit is chosen for analytical and experimentalwork.An interference fit is also known as a press fit or frictionfit is a fastening between two parts which is achieved byfriction after the parts are pushed together, rather than byany other means of fastening. These fits, thoughapplicable to shaft and hole assembly, are more oftenVolume 6, Issue 07LITERATURE REVIEWRahman Seifi and Kaveh Abbasi(2015)[1]. Reliable finiteelement modeling has a great degree of importance forstudies related to mechanical design in industry.Interference shaft \bush joints are under static as well asdynamic loads Strength of assemblies depends on amountof interference, material properties, physical dimension,friction co-efficient of contact surface,mating membersetc. Paper is examined using ANSYS software. Frictionco-efficient in contact surface is calculated.Chao Zeng et al(2016)[2]. This study shows the crackopening stress should not be a function of stress ratio withcrack length. Fatigue property is related to inducedresidual stress. The result shows that, with the presence offatigue cracks, the initial stress-strain state in the structurewould change, especially near the crack tip, where greatcompressive stress can be found.Stefan Kleditzsch et al (2014)[3]. This study shows theknurled fit which been established in industrialapplications because of their potential utility. Paper givesnumerical investigation of joining process of knurledPublished by, www.ijert.org1

Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference Proceedingsinterference fit and its influence on the loadcharacteristics of material. (1)For knurled interference fitsjoined by forming, QH influences the expansion of thehub and the process forces. (2) For knurled interferencefits joined by cutting, the influence of QH on theexpansion and the joining forces is negligible.Barmanov I.S and Ortikov M.N (2016)[4]. To study theinfluence of interference on the rolling element of a ballbearing for radial and axial displacement of the bearingrings. To quantify the change in dynamic characteristicsand durability of the bearing when there is change inamount of interference on the balls.Nelli Aleksandrova (2015)[5]. This paper examines aboutthe analytical research on strain analysis of dossubleshear reverted or bolted joints. The importance in thisstudy was validation of stress solution, i.e the completestress - strain field must be continuous. While modelingfastener-hole applications within the elastic-perfectlyplastic material, two different failure mechanisms shouldbe considered, namely, decohesive carrying capacity andlimit load carrying capacity.T.N. Chakherlou and B. Abazadeh(2012)[6]. In this paperthe fatigue behavior of double shear lap joints treated bydifferent combinations of interference fit and boltclamping have been investigated both experimentally andnumerically. The fatigue test results showed that a betterfatigue life improvement was achieved by employing thecombination of a smaller interference fit size and biggerclamping force. The fracture section of different types ofthe specimens showed that the fatigue crack initiationlocation depends on the applied cyclic load range.III.FIG 1: Meshed Model of Hole – Shaft AssemblyC)STRESS ANALYSIS OF MODEL:The equivalent force acting on the shaft part isgiven to FEA model. The value for the force is taken byreferring various journals and sources.FIG 2: Deformation on FEA ModelANALYTICAL WORKA)ANALYTICAL APPROACH:Analytical work is performed on ANSYS WORKBENCH17.2. In ANSYS workbench 17.2, the analysis of the hole– shaft assembly is done to evaluate the hole and shaftparts displacement, stresses acting on those parts andstrain values.B)PROCEDURES UNDER STATIC STRUCTURAL: Engineering Data Geometry Model Setup Solution ResultTABLE I: Material Properties Used For AnalysisMaterialPropertyDensityYoung’s ModulusPoisson’s RatioBulk ModulusShear ModulusTensile Yield StrengthTangent ModulusVolume 6, Issue 07Structural SteelValue7850 kg/m3200 GPa0.3166 GPa76 GPa200 Mpa2000 MpaFIG 3: Equivalent Stress on Hole-Shaft AssemblyTABLE II: Results of Stress and 4 MN/mm23.544 10 -5 mEXPERIMENTAL WORKS.NOMATERIALS USED1Mild SteelHigh Carbon HighChromium Steel (D3)2Published by, www.ijert.orgMinimum4.61 MN/mm20mMATERIALTYPESoft MaterialHardened Material2

Special Issue - 2018A)International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsDESIGN ATTRIBUTES:D)CYLINDRICAL GRINDINGFIG 4: Design of Hole – Shaft AssemblyB)LATHE WORK:FIG 7: Cylindrical Grinding MachineFIG 5: Lathe MachineC)HEAT TREATMENT:HARDNESS (HRC) – HCHCr STEELBEFORE HEATTREATMENTAFTER HEATTREATMENT2452FIG 8:FIG 8:E)(A) Before Grinding(B) After GrindingHYDRAULIC PRESSFIG 6: (A) Before Heat TreatmentFIG 9: Hydraulic Press WorkFIG 6 (B) After Heat TreatmentVolume 6, Issue 07Published by, www.ijert.org3

Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsF)WIRE-CUT ELECTRO DISCHARGEMACHININGWire Cut -Electrical Discharge Machining is a process ofmetal machining in which a tool discharges thousands ofsparks to a metal work-piece. Material is removed fromthe work-piece by a series of rapidly recurring currentdischarges between two electrodes, separated by adielectric liquid and subject to an electric voltage.G)SCANNING ELECTRON MICROSCOPESEM:Scanning electron microscope is a type of electronmicroscope that produces images of a sample by scanningthe surface with a focused beam of electrons. Theelectrons interact with atoms in the sample, producingvarious signals that contain information about thesample’s surface topography and composition. Theelectron beam is scanned in a raster scan pattern andbeam’s position is combined with the detected signal toproduce an image. SEM can achieve resolution betterthan 1 nanometer.SEM IMAGES:FIG 10: (A) WC – EDM MachineFIG 10: (B) Machining ProcessWC-EDM WORK SAMPLESFIG 12: Mild Steel Sample & (B) HCHCr SteelFIG 11: (A) Mild Steel PieceFIG 11 (B) HCHCr Steel PieceVolume 6, Issue 07V.CONCLUSIONIn general interference fit is the overlapping of shaft andhole mating parts. On reviewing various literature papers,it is found that standard interference values, frettingfatigue and cracking points on various materials are notdiscussed. To make realistic standard interference valuesare chosen from westermann tables in IS FITS withIS:919-1963 and IS:2709-1964 which is basically holesystem. Selected interference values are 33, 59, 73 micrometer. Interference values, diameter and length of holeparts are correlated in mini-tab software. Soft mild steeland hardened high carbon high chromium steels arechosen for analysis. Obtained correlation values aremodeled and analyzed with CREO software and ANSYSsoftware. ANSYS results provides the stress, strain anddeformation values with respect to applied interferencePublished by, www.ijert.org4