The kinetics of subcritical crack growth under sustained loading

1973 ◽  
Vol 9 (3) ◽  
pp. 277-293 ◽  
Author(s):  
J. D. Landes ◽  
R. P. Wei
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Sustained Loading ◽  
Kinetics Of

Scale effect of material structure on the similarity of subcritical crack growth under sustained loading

2012 ◽  
Vol 7 (4) ◽  
pp. 321-332 ◽  
Author(s):  
Ryuji Sugiura ◽  
A. Toshimitsu Yokobori Jr. ◽  
Toshihito Ohmi ◽  
Yoshiko Nagumo ◽  
Takashi Matsuzaki ◽  
...  
Keyword(s):  
Crack Growth ◽  
Scale Effect ◽  
Subcritical Crack Growth ◽  
Material Structure ◽  
Sustained Loading

Kinetics of Subcritical Crack Growth and Deformation in a High Strength Steel

1973 ◽  
Vol 95 (1) ◽  
pp. 2-9 ◽  
Author(s):  
J. D. Landes ◽  
R. P. Wei
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Activation Energies ◽  
Steady State Creep ◽  
Deformation Kinetics ◽  
Deformation Processes ◽  
Apparent Activation Energies ◽  
Kinetics Of

The kinetics of subcritical crack growth under sustained loading in a chemically inert environment (dehumidified argon) and the companion deformation kinetics were determined to examine the possible relationship between the crack growth and deformation processes in an AISI 4340 steel tempered at 400 deg F (∼205 degC). Crack growth experiments were carried out over a range of temperatures from 20 to 140 deg C, using the crack tip stress intensity factor K to chacterize the mechanical crack driving force. Deformation kinetics were determined as a function of deformed structure either at constant load or by a strain rate cycling procedure over the same range of temperatures. Detectable crack growth (with rates above 10−5 ipm) in dehumidified argon occurred at K levels exceeding about 70 percent of Kc at room temperature and 50 percent of Kc at the higher temperatures. Crack growth exhibited transient, steady-state and tertiary stages of growth, akin to creep, in agreement with the results of Li, et al. Experimental data indicate that subcritical crack growth in dehumidified argon is controlled by thermally activated processes, with apparent activation energies in the range of 11,000 to 18,000 cal/mole. This range of apparent activation energies is in general agreement with an observed range of 12,000 to 28,000 cal/mole for steady-state creep in this material. The apparent activation energies for steady-state creep were found to be dependent on flow stress and structure. Based on the similarity between the observed crack growth and deformation behaviors and on the order of magnitude agreement between the apparent activation energies, it is reasonable to consider that subcritical crack growth in inert environments is controlled by the time dependent deformation processes occurring at the crack tip. A model for relating steady-state crack growth and steady-state creep is suggested, and is shown to correlate well with experimental data.

Numerical evaluation of subcritical crack growth kinetics in structural adhesive joints under long static loading with cohesive zone model and experimental data

2021 ◽  
Vol 10 ◽  
pp. 74-84
Author(s):  
A. A. Ustinov ◽  
◽  
P. G. Babayevsky ◽  
N. A. Kozlov ◽  
N. V. Saliyenko ◽  
...  
Keyword(s):  
Experimental Data ◽  
Crack Growth ◽  
Static Loading ◽  
Cohesive Zone ◽  
Subcritical Crack Growth ◽  
Cohesive Zone Model ◽  
Adhesive Joints ◽  
Zone Model ◽  
Structural Adhesive ◽  
Kinetics Of

The article proposes a numerical method for modeling and calculating the kinetics of subcritical crack growth and creating kinetic G-V diagrams for structural adhesive joints under prolonged static loading. The load was set by the global subcritical crack opening according to mode I. Modeling and calculations were carried out using a cohesive zone model implanted into the finite element method in the ANSYS software package. The parameters of the cohesive zone law and the kinetics of subcritical crack growth were experimentally determined for samples in the form of a double cantilever beam made of aluminum alloy plates glued with industrial grade epoxy glue. Comparison of the calculated and experimental data showed a good correlation.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

Subcritical Crack Growth and Long-Term Strength in Rock and High-Strength and Ultra Low-Permeability Concrete

2009 ◽  
Vol 58 (6) ◽  
pp. 525-532 ◽  
Author(s):  
Yoshitaka NARA ◽  
Masafumi TAKADA ◽  
Daisuke MORI ◽  
Hitoshi OWADA ◽  
Tetsuro YONEDA ◽  
...  
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
High Strength ◽  
Low Permeability ◽  
Term Strength

Subcritical crack growth and in vitro lifetime prediction of resin composites with different filler distributions

2012 ◽  
Vol 28 (9) ◽  
pp. 985-995 ◽  
Author(s):  
Bárbara P. Ornaghi ◽  
Marcia M. Meier ◽  
Vinícius Rosa ◽  
Paulo F. Cesar ◽  
Ulrich Lohbauer ◽  
...  
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Lifetime Prediction ◽  
Resin Composites
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