Determination of dynamic fracture parameters using a semi-circular bend technique in split Hopkinson pressure bar testing

Fracture initiation toughness, fracture energy, fracture propagation toughness, and fracture velocity are key dynamic fracture parameters. We propose a method to simultaneously measure these parameters for mode-I fractures in split Hopkinson pressure bar (SHPB) testing with a notched semi-circular bend (SCB) specimen. The initiation toughness is obtained from the peak load given dynamic force equilibrium. A laser gap gauge (LGG) is developed to monitor the crack surface opening displacement (CSOD) of the specimen, from which the fracture velocity and the fracture energy can be calculated. The feasibility of this methodology for coarse-grained solids is demonstrated with the SHPB-SCB experiments on Laurentian granite.

[1]  B. Mohanty,et al.  Experimental calibration of stress intensity factors of the ISRM suggested cracked chevron-notched Brazilian disc specimen used for determination of mode-I fracture toughness , 2006 .

[2]  Weinong W Chen,et al.  Pulse shaping techniques for testing brittle materials with a split hopkinson pressure bar , 2002 .

[3]  M. N. James,et al.  Fracture toughness testing of hard metals using compression-compression precracking , 1990 .

[4]  Chun’an Tang,et al.  A new method for measuring dynamic fracture toughness of rock , 1990 .

[5]  M. J. Forrestal,et al.  A split Hopkinson bar technique for low-impedance materials , 1999 .

[6]  H. Vehoff,et al.  Precracking of NiAl single crystals by compression-compression fatigue and its application to fracture toughness testing , 1994 .

[7]  Chaoshui Xu,et al.  The Cracked Chevron Notched Brazilian Disc Test Geometrical Considerations For Practical Rock Fracture Toughness Measurement , 1993 .

[8]  B. Mohanty,et al.  Fracture toughness anisotropy in granitic rocks , 2008 .

[9]  Herbert Kolsky,et al.  Stress Waves in Solids , 2003 .

[10]  Per-Arne Lindqvist,et al.  Effects of loading rate on rock fracture , 1999 .

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

[12]  A. Bertram,et al.  Crack Propagation Toughness of Rock for the Range of Low to Very High Crack Speeds , 2003 .

[13]  K. Graff.  Wave Motion in Elastic Solids , 1975 .

[14]  Per-Arne Lindqvist,et al.  Effects of loading rate on rock fracture: fracture characteristics and energy partitioning , 2000 .

[15]  Daniel Casem,et al.  A Four-Point Bend Technique to Determine Dynamic Fracture Toughness of Ceramics , 2006 .

[16]  John W. Hutchinson,et al.  Dynamic Fracture Mechanics , 1990 .

[17]  Weinong Chen,et al.  Energy for Specimen Deformation in a Split Hopkinson Pressure Bar Experiment , 2006 .

[18]  D. Rittel,et al.  Dynamic fracture detection using the force-displacement reciprocity: application to the compact compression specimen , 1995 .

[19]  Ares J. Rosakis,et al.  Experimental Determination of Dynamic Crack Initiation and Propagation Fracture Toughness in Thin Aluminum Sheets , 1998 .

[20]  K. Ramesh,et al.  Technique for the continuous measurement of projectile velocities in plate impact experiments , 1995 .

[21]  K. P. Chong,et al.  New specimen for fracture toughness determination for rock and other materials , 1984 .

[22]  K. T. Ramesh,et al.  Finite deformations and the dynamic measurement of radial strains in compression Kolsky bar experiments , 1996 .

[23]  A. Ingraffea,et al.  STANDARDS FOR FRACTURE TOUGHNESS TESTING OF ROCK AND MANUFACTURED CERAMICS: WHAT CAN WE LEARN FOR CONCRETE? , 1997 .

[24]  R. Barsoum.  Triangular quarter‐point elements as elastic and perfectly‐plastic crack tip elements , 1977 .

[25]  A. Rosakis,et al.  Observing ideal ¿self-similar¿ crack growth in experiments , 2006 .

[26]  S. Suresh,et al.  Fracture toughness measurements in ceramics: Pre-cracking in cyclic compression , 1987 .

[27]  F. Ouchterlony.  On the background to the formulae and accuracy of rock fracture toughness measurements using ISRM standard core specimens , 1989 .

[28]  W. Böhme,et al.  The behavior of notched bend specimens in impact testing , 1982 .

[29]  M. J. Forrestal,et al.  Pulse shaping techniques for testing elastic-plastic materials with a split Hopkinson pressure bar , 2005 .

[30]  L. Griffiths,et al.  A study of the dynamic behaviour of a carbon-fibre composite using the split Hopkinson pressure bar , 1974 .