THE USE OF MARKOV CHAINS THEORY FOR APPROXIMATION OF ATIGUE CURVE OF COMPOSITE MATERIAL
Some simple mathematical model for fatigue life of composite m aterial consisting mainly of parallel rigidd components (strands) is offered.. The model,, whi chh is foundedd onn the use of Markov chainn theory,, allows too get S-type curve of internal stress growthh and, finally,, too s ee the connectionn betweenn static strengthh distributionn parameters andd S-N fatigue curve (Wholer curve).. The model is tooo simple andd does not provide numerica l coincidence with experimental fatigue test data but by the use of some additional parameters we cann fit the model too actual fatigue datasets,, we can use it for nonlinear regressionn model of S-N fatigue curveandd predict consequence of static strengthh parameter changes.
THE ESTIMATION OF PARAMETERS OF FATIGUE CURVE OF COMPOSITE MATERIAL
Maximum likelihood estimation of parameters of mathematical model of fatigue damage accumulation based on laminate fatigue life data processing is considered. The model, which is founded on the use of Markov chain theory, allows us to see connection between static strength distribution parameters and S-N fatigue curve. It was shown already that the model is too simple and does not provide numerical coincidence with experimental fatigue test data, nevertheless it could be used as nonlinear regression model of S-N fatigue curve. Simple method of approximate estimation of model parameters is offered. Numerical example is given. Some parameters of this fatigue curve model can be considered as local static strength distribution function parameters. Using this model, we can predict fatigue curve changes as consequence of static strength parameter changes.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).