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On the Errors Induced by the Hookean Modeling of Nominal Stresses in the eN Method
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 05, 2001 by SAE International in United States
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The traditional εN procedures are inconsistent when modeling nominal stresses by Hooke's law and the stresses and strains at the critical notch root by Ramberg-Osgood's equation, since the material is the same at both regions. When the nominal stresses are not substantially smaller than the yielding strength SY, the predicted hysteresis loops at the notch root can be significantly non-conservative. In fact, when the nominal stresses are in the order of SY, the Hookean model can predict stresses and strains at the notch root that are smaller than the nominal ones, a clear non-sense. To avoid this problem, it is mandatory to use Ramberg-Osgood to model both the nominal and the critical stresses and strains. However, this approach is not trivial to implement, especially when complex loads are involved. In this work, the methodology required to warrant correct numerical predictions of the critical loops under high nominal loads are discussed.
CitationMeggiolaro, M. and de Castro, J., "On the Errors Induced by the Hookean Modeling of Nominal Stresses in the eN Method," SAE Technical Paper 2001-01-4067, 2001, https://doi.org/10.4271/2001-01-4067.
- Bannantine, J.A., Comer, J.J., Handrock, J.L., Fundamentals of Metal Fatigue Analysis, Prentice Hall 1990.
- Duggan, T.V., Byrne, J., Fatigue as a Design Criterion, Macmillan 1977.
- Dowling, N.E., Mechanical Behavior of Materials, Prentice-Hall 1993.
- Farahmand, B., Fatigue and Fracture Mechanics of High Risk Parts, Chapman & Hall 1997.
- Fuchs, H.O., Stephens, R.I., Metal Fatigue in Engineering, Wiley 1980.
- Hertzberg, R.W., Deformation and Fracture Mechanics of Engineering Materials, Wiley 1989.
- Manson, S.S. “Fatigue: A Complex Subject - Some Simple Approximations”, Experimental Mechanics, v.5 n.4, pp.193-226, 1965.
- Mitchell, M.R., “Fundamentals of Modern Fatigue Analysis for Design”, in Fatigue and Microstructure, ASM 1979.
- Rice, R.C., ed., Fatigue Design Handbook, SAE 1988.
- Sandor, B.I., Fundamentals of Cyclic Stress and Strain, University of Wisconsin 1972.
- Castro, J.T.P., Meggiolaro, M.A., “Some Comments on the εN Method Automation for Fatigue Dimensioning under Complex Loading,” (in Portuguese), Revista Brasileira de Ciências Mecânicas, v. 21, pp.294-312, 1999.
- Castro, J.T.P., Meggiolaro, M.A., Projeto à Fadiga sob Cargas Complexas (in Portuguese), PUC-Rio 2001.
- Castro, J.T.P., Meggiolaro, M.A., “Automation of the Fatigue Design Under Complex Loading,” I Int. Fatigue Seminar SAE-Brasil, 2000-01- 3334, 2000.
- Topper, T.H., Wetzel, R.M., Morrow, JoDean, “Neuber's Rule Applied to Fatigue of Notched Specimens,” Journal of Materials, v. 4, no. 1, pp.200-209, 1969.
- Miranda, A.C.O., Meggiolaro, M.A., Castro, J.T.P., Martha, L.F., Bittencourt, T.N., “Fatigue Crack Propagation under Complex Loading in Arbitrary 2D Geometries,” Appl. of Autom. Tech. in Fatigue and Fract. Testing and Analysis, ASTM STP 1411, 2001.
- Meggiolaro, M.A., Castro, J.T.P., “ViDa 98 - a Visual Damagemeter to Automatize the Fatigue Design under Complex Loading,” (in Portuguese), Revista Brasileira de Ciências Mecânicas, v. 20, pp.666-685, 1998.
- Guizzo, T. “Laços de Histerese Elastoplásticos Gerados sob Carregamentos Complexos,” M.Sc. Thesis, Mech. Eng. Dept. PUC-Rio, 1999.