13th International Conference on Fracture June 16–21, 2013, Beijing, China -9- cracking within the KI-ind-dominant region around the contact edge. It is found that the critical indentation stress intensity factor exists, and the relation between the indentation fracture toughness KIC-ind and the common Mode-I fracture toughness KIC is established analytically, showing KIC-ind = 2.5KIC. The indentation-cracking angle at the contact edge is also determined. The present fracture mechanics model on surface contact cracking induced by a flat-tipped indenter provides a useful alternative for measuring the fracture toughness KIC, which can be useful for characterization of surface fracture properties of bulk elastic bodies and coating fracture properties of layered structures. Acknowledgements This work was supported by National Natural Science Foundation of China (Grant Nos. 50771052 and 50971068, 11272141), Gledden Senior Fellowship from the University of Western Australia and Natural Science Foundation of Liaoning (Grant Nos. LS2010100 and 20102129). References [1]. A.E. Giannakopoulos, T.C. Lindley, S. Suresh, Aspects of connections and life-prediction methodology for fretting-fatigue. Acta Mater, 46 (1998) 2955-2968. [2]. A.E. Giannakopoulos, T.A. Venkatesh, T.C. Lindley, S. Suresh, The role of adhesion in contact fatigue. Acta Mater, 47 (1999) 4653-4664. [3]. B. Yang, S. Mall, On crack initiation mechanism in fretting fatigue. ASME J Appl Mech, 68 (2001) 76-80. [4]. A.I. Nadai, Theory of flow and fracture of solids. New York: McGraw-Hill, 1963. [5]. Y.J. Xie, D.A. Hills, Quasibrittle fracture beneath a flat bearing surface. Eng Fract Mech, 75 (2008) 1223–1230. [6]. J.D. Eshelby, The force on an elastic singularity. Phil Trans Roy Soc London A 244 (1951) 87-112. [7]. G.C. Sih, Inelastic behaviour of solids. In: Sih GC editor. Dynamic aspects of crack aspects of crack propagation, New York: Mc-Graw-Hill Book, Co, 1969, pp.607-639. [8]. J.R. Rice, A path-independent integral and the approximate analysis of strain concentrated by notches and cracks. ASME J Appl Mech, 35 (1968) 379-386. [9]. B. Budiansky, J.R. Rice, Conservation laws and energy-release rates. ASME J Appl Mech 40 (1973) 201-203. [10]. A.A, Griffith, The Phenomena of rupture and flow in solids. Phil Trans Roy Soc London A 221 (1921) 163-198. [11]. G.P Cherepanov, Mechanics of brittle fracture. New York: McGraw-Hill International Book Co, 1979. [12]. Y.J. Xie, D.A. Hills, Quasibrittle fracture beneath a flat bearing surface. Engineering Fracture Mechanics 75 (2008) 1223–1230. [13]. Y.J. Xie, K.Y. Lee, X.Z. Hu, Y.M. Cai, Applications of conservation integral to indentation with a rigid punch. Engineering Fracture Mechanics 76 (2009) 949–957. [14]. Y.J. Xie, X.Z. Hu, X.H. Wang, J. Chen, K.Y. Lee, A theoretical note on mode-I crack branching and kinking. Engineering Fracture Mechanics 78 (2011) 919–929. [15]. Y.J. Xie, X.Z. Hu, X.H. Wang, Frictional contact induced crack initiation in incompressible substrate. Engineering Fracture Mechanics, 78 (2011) 2947–2956 [16]. Y. J. Xie, X. Z. Hu, J. Chen and K.Y. Lee, Micro-indentation fracture from flat-ended cylindrical indenter. Fatigue & Fracture of Engineering Materials & Structures, 35 (2012) 45– 55. [17]. X. Zhang, X.Z. Hu, Determination of fracture toughness of brittle polymers from contact crack induced by flat-tipped cylindrical indenter. Polymer Testing, 31 (2012) 765-769.
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