10 slanted fracture. In the MR(T) specimens, as well as in smooth tensile test specimens, nucleation of cracks and their extension both occur by one and the same mechanics of shear localisation. Although this study is still in progress, the experimental results appear to be sufficiently significant to make the following general conclusions. It seems likely that the CTOA- ψc concept needs to be modified with the aim of developing the more pragmatic approach to characterization of ductile tearing resistance. In the context of this problem, the MR(T) specimen of basic geometry might be sought as an attractive alternative to geometry of the standard M(T) specimen [8-10]. Acknowledgements I am deeply grateful to Mr. Limansky I.V. and Mr. Kravchuk, R.V. for kindly placing at my disposal the test data that were obtained in our jointly performed experimental investigation. References [1] V.P. Naumenko and G.S. Volkov, Assessment of plane stress tearing in terms of various crack-driving parameters, in: Fatigue and Fracture Mechanics, ASTM STP1461, S. R. Daniewicz, J. C.Newman, Jr., and K.-H. Schwalbe (Eds), West Conshohocken, PA: ASTM International, 34 (2003) 182-202. [2] V.P. Naumenko, A.G. Atkins, Engineering assessment of ductile tearing in uniaxial and biaxial tension. Int. J. Fatique, 28 (2006) No. 5-6, 494-503. [3] V.P Naumenko, S.V. Lenzion, I.V. Limansky, Displacement-based assessment of ductile tearing under low-constraint conditions. The Open Mechanical Engineering Journal, 2 (2008) 40-59. [4] V.P. Naumenko, Through-life assessment of ductile tearing under low-constraint conditions, in: Proc. of 12th Int. Conf. On Fracture, Elboujdaini M., (Ed.), Ottawa, 2009, 10 pages. [5] V.P. Naumenko, I.V Limansky, (2009), Energy-based assessment of ductile tearing in a thinsheet aluminium alloy. Procedia Engineering, 1 (2009) issue 1, 63-66. [6] V.P Naumenko, I.V Limansky, R.V Kravchuk, Elastic-plastic fracture under low-constraint conditions: Part I, Characteristic states of a cracked specimen. (2013), to be published in the journal Strength of Materials. [7] V.P Naumenko, I.V Limansky, R.V Kravchuk, Elastic-plastic fracture under low-constraint conditions: Part II, Fully developed crack. (2013), to be published in the journal Strength of Materials. [8] E561-74, Recommended practice for R-curve determination. ASTM Standard, 1974. [9] E2472-06. Standard test method for determination of resistance to stable crack extension under low-constraint conditions, ASTM Standard, 2007. [10] ISO 22889, Metallic materials - Method of test for the determination of resistance to stable crack extension using specimens of low constraint, International Standard, 2007.
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