An improved semi-circular bend specimen for investigating mixed mode brittle fracture

An edge cracked semi-circular specimen subjected to asymmetric three-point bend loading was suggested for investigating mixed mode fracture in brittle materials. Using finite element analysis, the crack parameters were obtained for various crack lengths and different locations of loading points. It was shown that by selecting appropriate positions for the loading points, full mode mixities from pure mode I to pure mode II could be achieved. Then, a series of fracture tests were conducted on PMMA using the proposed specimen. Very good agreement was found between the experimental results and those predicted from the generalized maximum tangential stress criterion.

[1]  J. G. Williams,et al.  Fracture under complex stress — The angled crack problem , 1984 .

[2]  I. L. Lim,et al.  Fracture testing of a soft rock with semi-circular specimens under three-point bending. Part 2—mixed-mode , 1994 .

[3]  M. Williams,et al.  On the Stress Distribution at the Base of a Stationary Crack , 1956 .

[4]  D. Munz,et al.  Fracture tests for ceramics under mode-I, mode-II and mixed-mode loading , 1995 .

[5]  H. Awaji,et al.  Combined Mode Fracture Toughness Measurement by the Disk Test , 1978 .

[6]  David Taylor,et al.  The effect of stress concentrations on the fracture strength of polymethylmethacrylate , 2004 .

[7]  Noel P. O’Dowd,et al.  Mixed-mode fracture toughness of ceramic materials , 1990 .

[8]  G. Sih.  Strain-energy-density factor applied to mixed mode crack problems , 1974 .

[9]  M. Ayatollahi,et al.  Brittle fracture evaluation of a fine grain cement mortar in combined tensile-shear deformation , 2009 .

[10]  M. Ayatollahi,et al.  Analysis of a new specimen for mixed mode fracture tests on brittle materials , 2009 .

[11]  A. R. Rosenfield,et al.  Mixed-mode fracture in biaxial stress state: Application of the diametral-compression (Brazilian disk) test , 1987 .

[12]  M. Pavier,et al.  On the consequences of T-stress in elastic brittle fracture , 2006, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[13]  A. R. Torabi,et al.  Determination of mode II fracture toughness for U-shaped notches using Brazilian disc specimen , 2010 .

[14]  Musharraf Zaman,et al.  Fracture toughness of a soft sandstone , 1998 .

[15]  F. Erdogan,et al.  On the Crack Extension in Plates Under Plane Loading and Transverse Shear , 1963 .

[16]  Mihai O. Marasteanu,et al.  Cohesive Modeling of Fracture in Asphalt Mixtures at Low Temperatures , 2005 .

[17]  M. Pavier,et al.  The role of T-stress in brittle fracture for linear elastic materials under mixed-mode loading , 2001 .

[18]  J. Knott,et al.  Effect of mixed mode I and II loading on the fracture surface of polymethyl methacrylate (PMMA) , 1995 .

[19]  Hans Albert Richard,et al.  A loading device for the creation of mixed mode in fracture mechanics , 1983 .

[20]  K. Chong,et al.  Fracture toughness determination of layered materials , 1987 .

[21]  Z. Hashin,et al.  A method to produce uniform plane-stress states with applications to fiber-reinforced materials , 1978 .

[22]  K. Ravi-Chandar,et al.  An experimental investigation of mixed-mode fracture , 1989 .

[23]  G. Xeidakis,et al.  Crack growth in a mixed-mode loading on marble beams under three point bending , 1996 .

[24]  Hussain,et al.  Strain Energy Release Rate for a Crack Under Combined Mode I and Mode II , 1974 .

[25]  M. Ayatollahi,et al.  Mixed mode brittle fracture in PMMA—An experimental study using SCB specimens , 2006 .

[26]  V. Tikare,et al.  Combined Mode I and Mode II Fracture of Monolithic Ceramics , 1993 .

[27]  J. Williams,et al.  Further results on the angled crack problem , 1976, International Journal of Fracture.

[28]  N. A. Al-Shayea,et al.  Effect of Specimen Geometry and Testing Method on Mixed Mode I–II Fracture Toughness of a Limestone Rock from Saudi Arabia , 2000 .

[29]  M. Ayatollahi,et al.  Geometry effects on fracture behaviour of polymethyl methacrylate , 2010 .

[30]  I. L. Lim,et al.  Stress intensity factors for semi-circular specimens under three-point bending , 1993 .

[31]  G. McKenna,et al.  Deformation, yield and fracture of polymers , 2012 .

[32]  Soo-Ho Chang,et al.  Measurement of rock fracture toughness under modes I and II and mixed-mode conditions by using disc-type specimens , 2002 .

[33]  M. Pavier,et al.  Mixed mode crack path investigation in a limestone rock using two circular shaped samples –An experimental and theoretical study , 2013, International Conference on Principles and Practice of Constraint Programming.

[34]  D. Zhu,et al.  Fracture behavior under mixed-mode loading of ceramic plasma-sprayed thermal barrier coatings at ambient and elevated temperatures , 2005 .

[35]  P. Theocaris.  A higher-order approximation for the T-criterion of fracture in biaxial fields , 1984 .

[36]  A. R. Torabi,et al.  Brittle fracture in rounded-tip V-shaped notches , 2010 .