Effect of Boundary Condition on Pre-Existing Crack Under Fatigue Loading
الموضوعات :V.K Singh 1 , P.C Gope 2 , R.K Bhagat 3
1 - Department of Mechanical Engineering, College of Technology, Govind Ballabh Pant University of Agriculture & Technology
2 - Department of Mechanical Engineering, College of Technology, Govind Ballabh Pant University of Agriculture & Technology
3 - Department of Mechanical Engineering, College of Technology, Govind Ballabh Pant University of Agriculture & Technology
الکلمات المفتاحية: Stress intensity factor, crack growth, Photo elasticity,
ملخص المقالة :
In this paper, the present investigation has been conducted keeping in mind some of the problems concerning the crack propagation direction and growth under constant loading in an inclined crack geometry. The present studies mainly focused on the development and modifications in the crack growth criterion to account the biaxial, shear loading and number of stress terms. Existing criteria for the prediction of crack initiation direction have been modified taking higher order stress terms. The effective methods of experimentally determining the stress intensity factor for a body containing a crack is to analyze the isochromatic pattern obtained from a photoelastic model. The effect of biaxial load factor, crack angle, Crack length/width of specimen and length of specimen/width of specimen were studied and a regression model was developed for geometry correction to predict stress intensity factor for tearing mode and intensity factor for shearing mode. This approach is being used to predict crack growth trajectory under biaxial cyclic loading by assuming that the crack may grow in a number of discrete steps using the vectorial method. MTS criterion (Maximum Tangential Stress criterion) is used for prediction of crack initiating angle. The crack growth trajectory has been determined by cycle simulation procedure.
[1] Irwin G.R., 1957, Analysis of stress strains near the end of a crack traversing plate, ASME Journal of Applied Mechanics 24(3): 361-364.
[2] Singh S., 1983, Applied Stress Analysis, Khanna Publishers, Second edition, Delhi, India: 346-347.
[3] Nash W., 2007, Strength of Materials, McGraw-Hill, Fourth edition, 7.1-7.44, New York.
[4] Ramesh K., Gupta S., Kelkar A.A., 1997, Evaluation of stress field parameter in fracture mechanics by photoelasticity, Engineering Fracture Mechanics 56(1): 25-45.
[5] Kelley L.G., 1991, Handbook of Numerical Method and Applications, Addison-Werly, p. 99.
[6] Erdogan F., Sih G.C., 1963, On crack extension in plates under plane loading transverse shear, ASME Journal of basic Engineering D 85: 519-527.
[7] Paris P.C., Erdogan F., 1963, A critical analysis of crack propagation laws, ASME Journal of basic Engineering D 85: 528-533.
[8] Khan Shafique M.A., Khraisheh M.K., 2000, Analysis of Mixed Mode Crack Initiation Angle under Various Loading Conditions, Elsevier science Ltd.: 1-10.
[9] Liebowitz H.., Lee J.D., Eftis J., 1978, Biaxial load effects in fracture mechanics, Engineering Fracture Mechanics 10: 315-335.
[10] Stephens R.I., Fatemi A., Stephens R. R., Fuchs H.O., 2001, Fatigue in Engineering, Second edition, John Wiley & Sons, Inc., New York.
