This monograph contains theoretical foundations of the spectral method for fatigue life determination where the authors discuss a rule of description of random loading states with the matrix of power spectral density functions of the stress/strain tensor components. Some chosen criteria of multiaxial fatigue failure being linear combinations of stress or strain components on the critical plane are analyzed.

The formula proposed in this book enables to determine power spectral density of the equivalent history directly from the components of the power spectral density matrix of the multidimensional stochastic process. It presents the assumptions and the procedure of determination of basic relationships of the spectral method. The authors work out equations determining the fatigue life according to the spectral method using various linear hypotheses of fatigue damage accumulation. The algorithm of fatigue life contains five blocks: 1 - determination of loading, 2 - determination of the critical plane position for the assumed multiaxial fatigue failure criterion, 3 - determination of power spectral density of the equivalent stress or strain, 4 - determination of statistical parameters of the equivalent parameter responsible for fatigue damage, and 5 - fatigue life calculation according to a suitable hypothesis of damage accumulation.

The book can be also recommended to postgraduate and PhD students with an interest in fatigue of engineering materials.

Zusammenfassung
Themonographisdevotedtothespectralmethodfordeterminationoffatigue life of machine elements and structures under multiaxial service loading. A detailed review of literature on spectral methods that includes: publications describing various relations between histories of loading and power spectral density functions, some methods of fatigue life determination under Ga- sian loading and under multiaxial service loading has been presented in the monograph. The monograph contains theoretical foundations of the spectral method for fatigue life determination. The authors have discussed a rule of description of random loading states with the matrix of power spectral d- sity functions of the stress/strain tensor components. Some chosen criteria of multiaxial fatigue failure being linear combinations of stress or strain com- nents on the critical plane have been analyzed. The proposed formula enables to determine power spectral density of the equivalent history directly from the components of the power spectral density matrix of the multidimensional stochastic process. The assumptions and the procedure of determination of basic relationships of the spectral method according to stress and strain - proacheshavebeen presented. The authors workedout equations determining the fatiguelife accordingto the spectralmethod using various linear hypot- ses of fatigue damage accumulation.

Inhalt
Spectral Methods for Fatigue Description.- Theoretical Fundamentals.- Algorithm of Spectral Method for Evaluation of Fatigue Life.- Simulations.- Experimental Studies.- Conclusions.