Summary
An experimental method is presented for the complete solution of the elastic-plastic plane stress problem of an edge-cracked plate obeying the Mises yield criterion and the Prandtl-Reuss incremental stress-strain flow rule. The material of the plate is assumed as a strain-hardened one with different degrees of hardening. The elastic and plastic components of strain were determined by using the method of birefringent coatings cemented on the surface of the metallic specimens made of the material under study. Normal incidence of circularly polarized light yielded the isolinics and isochromatics of the coating which provided the principal elastic strain differences and strain-directions at the interface. Evaluation of the stress intensity factor at the crack tip, by using the Griffith-Irwin definition, gave the sum of principal stresses at the crack tip. These data were sufficient to separate the components of strain at the coating-plate interface by using the classical shear-difference method.
The stress components on the partially plastically deformed cracked plate were determined by using the Prandtl-Reuss stress-strain relationships in a step-by-step process following the whole history of loading of the plate. Thus, a radial distribution law for the equivalent stress\(\bar \sigma \) and strain in all directions of the plate was established which gave the instantaneous position of the elastic-plastic boundary and its evolution during loading, as well as the distribution of elastic and plastic components of stresses allover the plate.
Four cases were solved for various amounts of strain-hardening from a quasi perfectly plastic material to an almost brittle strain hardened one. The values of the characteristic parameters defining each type of material were established.
The results derived compare excellently with existing ones based either on experimental or numerical solutions and since they are based on both the theory of elasticity and the incremental theory of plasticity they constitute a sound basis for comparison. Moreover, the algorithm based on this hybrid method is fast and stable requiring a minimum computer time, memory and data preparation.
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References
McClintock, F. A., Irwin, G. R.: Fracture toughness testing and its applications. ASTM-STP381, 84–113 (1965).
Willis, J. R.: Crack propagation in viscoelastic media. J. Mech. Phys. Solids15, 229–240 (1967).
Rice, J. R.: Mathematical analysis in the mechanics of fracture. In: Fracture, II, An advanced treatise (Liebowitz, H., ed.), pp. 191–311. New York: Academic Press 1968.
Rice, J. R., Rosengren, G. F.: Plane strain deformation near a crack tip in a power law hardening material. J. Mech. Phys. Solids16, 1–12 (1968).
Hutchinson, J. W.: Singular behavior at the end of a tensile crack in a hardening material. J. Mech. Phys. Solids16, 13–31 (1986).
Hutchinson, J. W.: Plastic stress and strain fields at a crack tip. J. Mech. Phys. Solids16, 337–347 (1968).
Hilton, P. D., Hutchinson, J. W.: Plastic intensity factors for cracked plates. Eng. Fract. Mech.3, 435–451 (1971).
Amazigo, J. C., Hutchinson, J. W.: Crack-tip fields in steady crack growth with linear strain hardening. J. Mech. Phys. Solids25, 81–97 (1977).
Edmunds, T. M., Willis, J. R.: Matched asymptotic expansions in nonlinear fracture mechanics-III. In plane loading of an elastic perfectly-plastic symmetric specimen. J. Mech. Phys. Solids25, 423–455 (1977).
Rice, J. R., Sorensen, E. P.: Continuing crack-tip deformation and fracture for plane strain crack growth in elastic-plastic solids. J. Mech. Phys. Solids26, 163–186 (1978).
Begley, J. A., Landes, J. D.: Serendipity and theJ-integral. Int. Fracture12, R764-R766 (1976).
Begley, J. A., Landes, J. D.: TheJ-integral as a fracture criterion. In: Fracture toughness (Corten, H. T., ed.) The 1971 National Symposium of Fracture of Mechanics, Part II, ASTM-STP514, 1–20 (1972).
Green, G., Knott, J. F.: On effects of thickness on ductile crack growth in mild steel. J. Mech. Phys. Solids23, 167–183 (1975).
Theocaris, P. S., Mylonas, C.: Viscoelastic effects in birefringent coatings. J. Appl. Mech.28, 601–607 (1961).
Theocaris, P. S., Gdoutos, E.: Matrix theory of photoelasticity. Berlin Heidelberg New York: Springer 1979 (Optical science series vol 11).
Theocaris, P. S.: Combined photoelastic and electrical analog method for solution of plane-stress plasticity problems. Exp. Mech.3, 207–214 (1963).
Theocaris, P. S.: Experimental solution of elastic-plastic plane stress problems. J. Appl. Mech.29, 735–743 (1962).
Theocaris, P. S., Marketos, E.: The elastic-plastic strain and stress distribution in notched plates under conditions of plane stress. J. Mech. Phys. Solids11, 411–428 (1963).
Theocaris, P. S., Marketos, E.: Elastic plastic analysis of perforated thin strips of a strain hardening material. J. Mech. Phys. Solids12, 377–390 (1964).
Theocaris, P. S.: The evolution of stress distribution in plane-stress contained plasticity problems. In: Proc. 11th Intern. Congr. Appl. Mech. (Görtler, H., ed.), pp. 569–574. Berlin Heidelberg New York: Springer 1965.
Theocaris, P. S., Gdoutos, E.: Verification of the validity of the Dugdale-Barenblatt model by the method of caustics. Eng. Fract. Mech.6, 523–535 (1974).
Theocaris, P. S., Gdoutos, E.: The modified Dugdale-Barenblatt model adapted to various fracture configurations in metals. Int. Fracture10, 549–564 (1974).
Theocaris, P. S.: Dugdale models for two collinear unequal cracks. Eng. Fract. Mech.18, 545–559 (1983).
Theocaris, P. S.: Dugdale type crack tip plasticity in orthotropic plates studied by caustics. Eng. Fract. Mech.41, 283–297 (1992).
Theocaris, P. S.: Experimental evaluation of the plastic zone for steady mode-III crack growth. Acta Mech.69, 271–294 (1987).
Theocaris, P. S., Philipps, Th.: Plastic stress intensity factors in out-of-plane shear by reflected caustics. Eng. Fract. Mech.27, 299–314 (1987).
Theocaris, P. S.: Stress intensities in elastic-plastic plane-stress field by caustics. Acta Mech.87, 219–238 (1991).
Stimpson, L. D., Eaton, D. M.: The extent of elasto-plastic yielding at the crack point of an externally notched plane-stress tensile specimen. Rep. ARL-24, Aeronautical Research Laboratory (1961).
Muskhelishvili, N. I.: Some basic problems of the mathematical theory of elasticity. Leyden: Noordhoff 1963.
Wigglesworth, L. A.: Stress distribution in a notched plate. Mathematica4, 76–96 (1957).
Bowie, O. L., Neal, D. M.: Single edge-crack in rectangular tensile sheet. J. Appl. Mech.32, 708–709 (1965).
Hill, R.: The mathematical theory of plasticity. Oxford: Oxford University Press 1950.
Allen, D. N. de G., Southwell, R.: Relaxation methods applied to engineering problems. XIV Plastic straining in two-dimensional stress systems. Phil. Trans. Royal Soc. (London)A 242(2), 379–416 (1950).
Theocaris, P. S.: Ductile fracture in glassy polymers. Int. J. Mech. Sci.17, 475–485 (1975).
Tuba, I. S.: An analytical method for elastic-plastic solutions. Int. J. Solids Struct.3, 543–564 (1967).
Marcal, P. V., King, I. P.: Elastic-plastic analysis of two dimensional stress systems by the finite element method. Int. J. Mech. Sci.8, 143–155 (1967).
Frocht, M. M.: Photoelasticity, Vol. I, pp. 252–285. New York: J. Wiley 1949.
Theocaris, P. S., Coroneos, A.: Stress-strain and contraction ratio curves for polycrystalline steel. The Phil. Magazine8, 1871–1893 (1963).
Theocaris, P. S.: On the use of theT-criterion in fracture mechanics (discussion). Eng. Fract. Mech.24, 371–382 (1986).
Gifford, N., Hilton, P. D.: PAPST non-linear fracture and stress analysis by finite elements. David Taylor naval ship research and development center Bethesda, Maryland 1-75 (1981).
Frocht, M. M.: Elastic-plastic solutions for notched shafts in tension. J. Appl. Mech.33, 954–956 (1966).
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Theocaris, P.S. Elastic-plastic analysis of cracked plates in plane stress: An experimental study. Acta Mechanica 99, 75–93 (1993). https://doi.org/10.1007/BF01177236
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DOI: https://doi.org/10.1007/BF01177236