APROXIMATION OF FATIGUE CURVE AND FATIGUE LIMIT OF FIBRE COMPOSITE USING RANDOM DANIELS' SEQUENCE AND MARKOV CHAINS

The possibility of using a model based on random Daniels' sequence and Markov chain theory for approximation of S-N fatigue curve of fiber reinforced material is studied. The model allows observing the connection between static strength distribution parameters and parameter of S-N fatigue curve. Although the model is too simple and does not provide numerical correspondence with experimental fatigue test data, it can explain the existence of a fatigue limit and can be used as a nonlinear regression model of S-N fatigue curve when taking into account the existence of a random fatigue limit. By using of this model fatigue curve (and especially, fatigue limit) changes as a consequence of tensile strength parameter changes may be predicted. A numerical example of carbon-fiber fatigue test dataset processing is provided.