Local stress and strain during crack growth by steady state creep

1977 ◽  
Vol 12 (10) ◽  
pp. 2099-2108 ◽  
Author(s):  
J. T. Barnby ◽  
R. D. Nicholson
Keyword(s):  
Steady State ◽  
Crack Growth ◽  
Local Stress ◽  
Steady State Creep ◽  
Stress And Strain

scholarly journals Creep Modeling in a Composite Rotating Disc with Thickness Variation in Presence of Residual Stress

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Vandana Gupta ◽  
S. B. Singh
Keyword(s):  
Residual Stress ◽  
Steady State ◽  
Creep Behavior ◽  
Yield Criterion ◽  
Steady State Creep ◽  
Thickness Variation ◽  
Stress And Strain ◽  
Rotating Disc ◽  
Varying Thickness ◽  
Von Mises

Steady-state creep response in a rotating disc made of Al-SiC (particle) composite having linearly varying thickness has been carried out using isotropic/anisotropic Hoffman yield criterion and results are compared with those using von Mises yield criterion/Hill's criterion ignoring difference in yield stresses. The steady-state creep behavior has been described by Sherby's creep law. The material parameters characterizing difference in yield stresses have been used from the available experimental results in literature. Stress and strain rate distributions developed due to rotation have been calculated. It is concluded that the stress and strain distributions got affected from the thermal residual stress in an isotropic/anisotropic rotating disc, although the effect of residual stress on creep behavior in an anisotropic rotating disc is observed to be lower than those observed in an isotropic disc. Thus, the presence of residual stress in composite rotating disc with varying thickness needs attention for designing a disc.

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.

Creep Crack Growth in X20CrMoV 12 1 Steel and Its Weld Joint

2000 ◽  
Vol 123 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Y. K. Park ◽  
K. S. Kim ◽  
Y. K. Chung ◽  
J. J. Park
Keyword(s):  
Steady State ◽  
Crack Growth ◽  
Weld Joint ◽  
Computational Study ◽  
Creep Crack Growth ◽  
Steady State Creep ◽  
Creep Crack ◽  
Creep Analysis ◽  
Calculated Load ◽  
Crack Growth Rates

A combined experimental and computational study is carried out on creep crack growth in X20CrMoV 12 1 steel and its weld joint. Crack growth tests are conducted on compact specimens at 545°C. For weld specimens, the crack propagates in the heat-affected zone parallel to the fusion line. It is found that C*t correlates crack growth rates satisfactorily under the loads used in the test not only for base metal specimens but also for weld specimens. An elastic-plastic-steady-state creep analysis of crack growth is performed using a finite element code. Calculated load point displacement rates agree with experimental measurements during steady-state crack growth. The creep zone is asymmetric, and it becomes more so in weld specimens as the crack propagates. Yet the mode II effect appears to be insignificant.

Mathematical Model of the Effective Properties of a Fiber Reinforced Composite with a Linearly Graded Transition Zone

2010 ◽  
Vol 38 (4) ◽  
pp. 286-307
Author(s):  
Carey F. Childers
Keyword(s):  
Mathematical Model ◽  
Transition Zone ◽  
Effective Properties ◽  
Local Stress ◽  
Stress And Strain ◽  
Fiber Reinforced ◽  
Strain Fields ◽  
Shear Moduli ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Abstract Tires are fabricated using single ply fiber reinforced composite materials, which consist of a set of aligned stiff fibers of steel material embedded in a softer matrix of rubber material. The main goal is to develop a mathematical model to determine the local stress and strain fields for this isotropic fiber and matrix separated by a linearly graded transition zone. This model will then yield expressions for the internal stress and strain fields surrounding a single fiber. The fields will be obtained when radial, axial, and shear loads are applied. The composite is then homogenized to determine its effective mechanical properties—elastic moduli, Poisson ratios, and shear moduli. The model allows for analysis of how composites interact in order to design composites which gain full advantage of their properties.

Reliability Simulation and Forecast Based on Virtual Prototype for the Running System of Complicated Equipments

2014 ◽  
Vol 543-547 ◽  
pp. 195-198
Author(s):  
Li Jun Cao ◽  
Hui Bin Hu ◽  
Gui Bo Yu ◽  
Shu Hai Wang
Keyword(s):  
Probability Density ◽  
Local Stress ◽  
Virtual Prototype ◽  
Probability Density Distribution ◽  
Stress And Strain ◽  
Load Spectrum ◽  
Density Distribution Function ◽  
Running System ◽  
Maintenance Cycle ◽  
Damage Theory

The running system is the key part to finish training or battle tasks of complicated equipments. But formidable working conditions influence the measurement of load spectrums and it is difficult to analyze and forecast the reliability of running system. Actual vehicle experiments and virtual prototype are firstly combined to obtain complete load spectrum of running system. According to the materials S-N curve, stress and strain spectrums can be computed. Nominal stress method and local stress and strain method are combined with probability density accumulation damage theory to compute the probability density distribution function. Then, the reliability of running system can be forecasted, which provide adequate reference for the maintenance cycle confirmation and mission reliability prediction.

Sign in / Sign up

Export Citation Format

Share Document