Stochastic approach to modeling fatigue crack growth

AIAA Journal ◽  
1989 ◽  
Vol 27 (11) ◽  
pp. 1628-1635 ◽  
Author(s):  
B. F. Spencer ◽  
J. Tang ◽  
M. E. Artley
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stochastic Approach

A Stochastic Approach of Thermal Fatigue Crack Growth (LEFM) in Mixing Tees

2010 ◽  
Author(s):  
Vasile Radu ◽  
Elena Paffumi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Frequency Response ◽  
Crack Growth ◽  
Response Function ◽  
Thermal Fatigue ◽  
Frequency Response Function ◽  
Narrow Band ◽  
Stochastic Approach ◽  
Thermal Fatigue Crack

The assessment of fatigue crack growth due to turbulent mixing of hot and cold coolants presents significant challenges, in particular to determine the thermal loading spectrum. Thermal striping is defined as a random temperature fluctuation produced by incomplete mixing of fluid streams at different temperatures, and it is essentially a random phenomenon in a temporal sense. The objective of this work is to develop a stochastic model to assess thermal fatigue crack growth in mixing tees, based on the power spectral density (PSD) of the temperature fluctuation at the inner pipe surface. Based on the analytical solution for temperature distribution through the wall thickness, obtained by means of Hankel transform, a frequency temperature response function is proposed, in the framework of single-input, single-output (SISO) methodology from random noise/signal theory under sinusoidal input. For the elastic thermal stresses distribution solutions, the magnitude of the frequency response function is first derived and checked against the prediction by FEA. The frequency response of the stress intensity factor (SIF) is obtained by a polynomial fitting of the stress profiles through the wall thickness at various instants of time. The variability in load is given by the statistical properties of thermal spectrum. The temperature spectrum is assumed to be given as a stationary normalized Gaussian narrow-band stochastic process, with constant PSD for a defined range of frequencies. The connection between SIF’s PSD and temperature’s PSD is assured with SIF frequency response function modulus. The frequency of the peaks of each magnitude for KI, which is supposed to be a stationary narrow-band Gaussian process, is characterized by the Rayleigh distribution, and, consequently, the expected value of crack growth rate in respect to cycles is obtained. The probabilities of failure are estimated by mean of the Monte Carlo methods considering a limit state function, which is based on the developed stochastic model. The results of the stochastic approach of thermal fatigue crack growth in mixing tees is completed with probabilistic input to account for the variability in the material characteristics, and finally an application is given to obtain the probability of mixing tees piping failure as function of time reference period.

A stochastic approach to modeling fatigue crack growth

1988 ◽  
Author(s):  
B. SPENCER, JR. ◽  
J. TANG ◽  
M.E. ARTLEY ◽  
H. STORR, JR.
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stochastic Approach

A discrete dislocation analysis of fatigue crack growth

2001 ◽  
Vol 11 (PR5) ◽  
pp. Pr5-69-Pr5-75
Author(s):  
V. S. Deshpande ◽  
H. H.M. Cleveringa ◽  
E. Van der Giessen ◽  
A. Needleman
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Discrete Dislocation

Fatigue Investigation of Elastomeric Structures

2010 ◽  
Vol 38 (3) ◽  
pp. 194-212 ◽  
Author(s):  
Bastian Näser ◽  
Michael Kaliske ◽  
Will V. Mars
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Material Behavior ◽  
Period Effect ◽  
Numerical Representation ◽  
Material Force ◽  
Strain Behavior ◽  
Dissipative Effects ◽  
Elastomeric Materials

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.

Expert system model of small fatigue crack growth

1998 ◽  
Author(s):  
D. Steadman ◽  
R. Carlson ◽  
G. Kardomateas
Keyword(s):  
Fatigue Crack ◽  
Expert System ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
System Model ◽  
Small Fatigue Crack
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