A simple second order approximation for stochastic crack growth analysis

Stochastic crack growth analysis methodologies for metallic structures

Stochastic fatigue, fracture and damage analysis

Crack propagation analysis is a major task in the design and life prediction of fatigue‐critical structures, yet experimental tests indicate that fatigue crack propagation involves a large amount of statistical variation and is not adequately modeled deterministically. A method of analysis based on Markov process theory is presented for the investigation of fatigue crack propagation. A new fracture mechanics based, lognormal random process model is developed, and without approximation, a boundary value problem is formulated for the statistical moments of the random time to reach a given crack size. A Petrov‐Galerkin finite element method is then used to obtain solutions to the boundary value problem. A parametric study of the power‐law fatigue crack growth model is conducted, and a numerical example is given in which excellent agreement is found between the finite element results and experimental data. The model and problem formulation are consistent with physical phenomena, overcome many objections to pr...

Markov process model for fatigue crack growth

Ce modele considere la fissuration comme un processus de Markov vectorise 2D. Deux lois de propagation des fissures de fatigue sont utilisees pour l'analyse, et une methode des integrales finies modifiee est proposee pour determiner les parametres du modele stochastique. Ce modele utilise les donnees de Virkler. Excellent accord entre les resultats theoriques et les donnees experimentales

Stochastic approach to modeling fatigue crack growth

Deterministic fatigue crack propagation models, such as the Paris-Erdogan model, cannot account for random variability of time-histories observed in experiments. Therefore, more realistic models are proposed in which a random process is introduced as a multiplicative factor to deterministic laws. This factor is assumed to be a train of randomly arriving pulses with random amplitudes, permitting simple computation of the statistical properties of the fatigue crack size at any given time. Approximate probability distributions can then be calculated using a general scheme called cumulant-neglect closure. Results obtained from retaining only the first two cumulants are compared with available experimental data and with previously calculated distributions when the crack size was treated as a Markov process.

Y. K. Lin

Papers

Stochastic Modeling of Fatigue Crack Propagation