Skip to main content
Log in

A practical randomization approach of deterministic equation to determine probabilistic fatigue and fracture behaviours based on small experimental data sets

  • Original Paper
  • Published:
International Journal of Fracture Aims and scope Submit manuscript

Abstract

This paper outlines a new technique to address the paucity of data in determining fatigue and fracture performances based on reliability concepts. Two new randomized models of time-dependent processes are presented for estimating the P–a–t and P–S–N curves, by using a randomization approach of deterministic equations, dealing with small sample numbers of data. The confidence level formulations for these curves are also given. The concepts are then applied for the determination of the P–a–t and P–S–N curves. Two sets of fatigue and fracture tests for these curves are conducted to validate the presented method, demonstrating the practical use of the proposed technique.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Abbreviations

a :

crack length

a 0 :

initial crack size

\(\hat{{a}}\) :

crack size difference

a(t):

crack length dependent on time t

b 1 :

undetermined parameter of linear regression equation

b 2 :

undetermined parameter of linear regression equation

b i :

undetermined material constant

C :

undetermined material constant

c i :

undetermined material constant

D(x):

standard deviation of variable x

E(x):

expected value of variable x

F :

non-negative function

f(x):

probability density function

K :

stress intensity factor

K max :

spectrum peak stress intensity factor

K C :

facture toughness

L :

likelihood function

L xx :

transformation variable of parameter estimation

L yy :

transformation variable of parameter estimation

L xy :

transformation variable of parameter estimation

m :

undetermined material constant

m i :

undetermined material constant

n :

sample size, or undetermined material constant of crack growth law

N :

fatigue life, or cycles of cyclic loading

N p :

safe fatigue life with a p percent reliability level

p :

reliability level

Q :

transformation variable

R :

stress ratio

s :

standard deviation of the sample

S :

fatigue strength, or stress amplitude, or peak stress level in the loading spectrum

S 0 :

undetermined material constant

S min :

minimum stress

S max :

maximum stress

t :

statistical variable, or time, or number of cycles

t 0 :

initial time

t γ :

γ percentile of t-distribution

u p :

standard normal deviator corresponding to the reliability level of p

u γ :

standard normal deviator corresponding to the confidence level of γ

U :

statistical variable

\(\bar{{x}}\) :

sample mean of random variable X

Y :

random variable

Y(a):

stress intensity boundary correction factor

\(\bar{{y}}\) :

sample mean of random variable Y

y p :

percentiles of random variable Y pertinent to reliability level p

y pγ :

one-side low limit of random variable Y corresponding to the probability of survival of p and the confidence level of γ

Z(a):

normal random process dependent on crack size a

α 0 :

plane stress/strain constraint factor

β:

correction coefficient of the standard deviation

γ:

confidence level

ω:

frequency in radians per second

υ:

degrees of freedom

χ 2 :

statistical variable

μ:

population mean value

σ:

standard variation of random variable

σ z :

standard deviation of normal random process Z(a)

τ 0 :

undetermined material constant

\(\Delta K\) :

stress intensity factor range

\(\Delta K_{th} \) :

fracture threshold value

References

  • Artley ME et al (1979) Variations in crack growth rate behaviour. 11th fracture mechanics conference, ASTM STP 677, 54–67

  • Bogdanoff JL and Kozin F (1985). Probabilistic models of cumulative damage. Wiley, New York

    Google Scholar 

  • Chatfield C (1983). Statistics for technology. Chapman and Hall, London

    MATH  Google Scholar 

  • Ditlevsen O and Olesen R (1986). Statistical analysis of the Virkler data on fatigue crack growth. Eng Frac Mech 25: 177–195

    Article  Google Scholar 

  • Forman RG (1967). Numerical analysis of crack propagation in cyclic loaded structures. J Basic Eng, Transaction ASME (Sereis D) 89: 459–465

    Google Scholar 

  • Freudenthal AM, Garrelts M and Shinozuka M (1966). The analysis of structural safety. J Struct Div, ASCE 92: 267–325

    Google Scholar 

  • Gallagher JP (1976). Estimating fatigue-crack lives for aircraft: techniques. Exp Mech 16: 425–433

    Article  Google Scholar 

  • Hoeppner DW and Krupp WE (1974). Prediction of component life by application of fatigue crack growth knowledge. Eng Frac Mech 6: 47–70

    Article  Google Scholar 

  • Lin YK, Wu WF and Yang JN (1985). Stochastic modeling of fatigue crack propagation: probabilistic methods in mechanics of solids and structure. Springer, Berlin

    Google Scholar 

  • Lin YK and Yang JN (1983). On statistical moments of fatigue crack propagation. Eng Frac Mech 18: 243–256

    Article  Google Scholar 

  • Miller MS and Gallagher GP (1981). An analysis of several fatigue crack growth rate descriptions.. Measurement Data Analysis, ASTM STP 738: 205–251

    Google Scholar 

  • Newman JC Jr (1984). A crack opening equation for fatigue crack growth. Int J Frac 24: 131–135

    Article  Google Scholar 

  • Paris PC and Erdogan FA (1963). critical analysis of crack propagation laws. J Basic Eng, Transaction ASME (Sereis D) 85: 528–534

    Google Scholar 

  • Proven JW (1987). Probabilistic fracture mechanics and reliability. Martinus Nijhoff, Dordrecht (The Netherlands)

    Google Scholar 

  • Ray A and Patankar RA (1999). stochastic model of fatigue crack propagation under variable-amplitude loading. Eng Frac Mech 62(4–5): 477–493

    Article  Google Scholar 

  • Rudd JL, Yang JN, Manning SD, Garver WR (1982) Durability design requirements and analysis for metallic airframes. Design of fatigue fracture resistant structures, ASTM STP 761, pp. 133–151

  • Sobczyk K and Spencer BF (1992). Random fatigue: from data to theory. Academic Press, Boston

    MATH  Google Scholar 

  • Trantina GG, Johnson CA (1983) Probabilistic defect size analysis using fatigue and cyclic crack growth rate data. Probabilistic fracture mechanics and fatigue methods, ASTM STP 798, pp 67–78

  • Tsurui A and Ishikawa H (1986). Application of the Fokker-Planck equation to a stochastic fatigue crack growth model. Struct Saf 4(1): 15–29

    Article  Google Scholar 

  • Virkler DA, Hillberry BM and Goel PK (1979). The statistical nature of fatigue crack propagation. J Eng Mat Technol, Transactions of ASME 101: 148–153

    Google Scholar 

  • Walker EK (1970) The effect of stress ratio during crack propagation and fatigue for 2024-T3 and 7075-T6 aluminum. Effects of environment and complex load history and fatigue life, ASTM STP 462, pp 1–14

  • Weibull W (1961). Fatigue testing and analysis of results. Macmillan Company, New York

    Google Scholar 

  • Wu WF and Ni CC (2003). A study of stochastic fatigue crack growth modeling through experimental data. Prob Eng Mech 18(2): 107–118

    Article  Google Scholar 

  • Wu WF and Ni CC (2004). Probabilistic models of fatigue crack propagation and their experimental verification. Prob Eng Mech 19(3): 247–257

    Article  Google Scholar 

  • Xiong J and Gao Z (1997). Probability distribution of fatigue damage and statistical moment of fatigue life. Sci China (Series E) 40(3): 279–284

    MATH  Google Scholar 

  • Yang JN and Donath RC (1983). Statistical fatigue crack propagation in fastener holes under spectrum loading. J Aircraft 20: 1028–1032

    Article  Google Scholar 

  • Yang JN and Manning SD (1990). Stochastic crack growth analysis methodologies for metallic structures. Eng Frac Mech 37: 1105–1124

    Article  Google Scholar 

  • Yang JN and Manning SD (1996). A simple second order approximation for stochastic crack growth analysis. Eng Frac Mech 53(5): 677–686

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to R. A. Shenoi.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Xiong, J.J., Shenoi, R.A. A practical randomization approach of deterministic equation to determine probabilistic fatigue and fracture behaviours based on small experimental data sets. Int J Fract 145, 273–283 (2007). https://doi.org/10.1007/s10704-007-9116-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10704-007-9116-z

Keywords

Navigation