Title

Extreme value probabilistic model for fatigue life in brittle plates with random cracks

Abstract

Fatigue life prediction is a subject of great interest for gas turbine components (Shin (1980), Tryon (1995)). Few if any models are available which rigorously apply fatigue criteria together with extreme value methods to predict fatigue life. The present study introduces a probabilistic model in which established criteria based on fracture mechanics are used for mixed-mode fatigue crack growth and eventual failure. The crack number, length and orientation at the onset of fatigue are random variables. Recently, for static fracture under fixed load, the authors introduced a conditional probability model leading to a probability density function (PDF) for the strength of brittle plates (more generally two dimensional media) with random cracks under mixed mode and multiaxial loading. (Ni (1996), Nicholson and Ni (1997-a), Nicholson and Ni (1997-b)). Unlike the few previous models involving extreme value methods (Trustrum (1977), Ichikawa (1995), She (1993)), the formulation is not restricted with respect to crack number or length. The present study extends the probabilistic model to fatigue life under fluctuating load. An explicit probability density function is derived for Nf, the number of cycles to plate failure. Biaxial loading and torsion are accommodated. The mean and variance of Nf are computed to show dependence on plate size, on the variance of the crack length distribution, on the multiaxial load factors, and on the parameters of the fatigue model.

Publication Date

12-1-1997

Publication Title

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP

Volume

356

Number of Pages

53-58

Document Type

Article

Personal Identifier

scopus

Socpus ID

0030677846 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/0030677846

This document is currently not available here.

Share

COinS