Markov Model of Fatigue of a Composite Material with Poisson Process of Defect Initiation

Mechanics of Composite Materials 2012
Jurijs Paramonovs, Rafal Andrzej Chatys, J. Andersons, Mārtiņš Kleinhofs

As a development of the model where only one weak microvolume (WMV) and only a pulsating cyclic loading are considered, in the current version of the model, we take into account the presence of several weak sites where fatigue damage can accumulate and a loading with an arbitrary (but positive) stress ratio. The Poisson process of initiation of WMVs is considered, whose rate depends on the size of a specimen. The cumulative distribution function (cdf) of the fatigue life of every individual WMV is calculated using the Markov model of fatigue. For the case where this function is approximated by a lognormal distribution, a formula for calculating the cdf of fatigue life of the specimen (modeled as a chain of WMVs) is obtained. Only a pulsating cyclic loading was considered in the previous version of the model. Now, using the modified energy method, a loading cycle with an arbitrary stress ratio is " transformed" into an equivalent cycle with some other stress ratio. In such a way, the entire probabilistic fatigue diagram for any stress ratio with a positive cycle stress can be obtained. Numerical examples are presented.

Keywords
Markov Model of Fatigue of a Composite Material with Poisson Process of Defect Initiation
DOI
10.1007/s11029-012-9267-5
Hyperlink
http://link.springer.com/article/10.1007%2Fs11029-012-9267-5

Paramonovs, J., Chatys, R., Andersons, J., Kleinhofs, M. Markov Model of Fatigue of a Composite Material with Poisson Process of Defect Initiation. Mechanics of Composite Materials, 2012, Vol.48, Iss.2, pp.217-228. ISSN 0191-5665. e-ISSN 1573-8922. Available from: doi:10.1007/s11029-012-9267-5

Publication language
English (en)