The creep crack problem in damaged materials under mixed mode loading is considered. The class of the self-similar solutions to the plane creep crack problems in a damaged medium under mixed-mode loading is given. With the similarity variable and the self-similar representation of the solution for a power-law creeping material and the power-law damage evolution equation the near crack-tip stresses, creep strain rates and continuity distributions for plane stress conditions are obtained. The self-similar solutions are based on the hypothesis of the existence of the completely damaged zone near the crack tip. It is shown that the asymptotical analysis of the near crack-tip fields gives rise to the nonlinear eigenvalue problems. The technique permitting to find the eigenvalues numerically is proposed and numerical solutions of the nonlinear eigenvalue problems arising from the mixed-mode crack problems in a power-law medium under plane stress conditions are obtained. Using the approach the eigenvalues different from the eigenvalues corresponding to the Hutchinson-Rice-Rosengren (HRR) problem are found. Having obtained the eigenspectra and eigensolutions the geometry of the completely damaged zone in the vicinity of the crack tip can be found for all values of the mixity parameter.

The paper is devoted to experimental study of the crack propagation direction angles under mixed mode loading in the plate with the central crack inclined at different angles. Fracture mechanics criteria are discussed and compared. In the present paper the crack propagation direction angles on the basis of three different fracture criteria are found. The maximum tangential stress criterion, the minimum strain energy density criterion and the deformation criterion are used and analysed. The generalized forms of these criteria have been used. It implies that the crack propagation direction angles are obtained with the Williams series expansion in which the higher order terms are kept. The calculations are performed in Waterloo Maple computer algebra software. The analysis of the crack propagation direction angles show that the influence of the higher order terms cant be ignored. The angles differ considerably when the higher order terms are taken into account.

АннотацияЦель. Описать и проанализировать инновационные подходы к развитию ресурсного потенциала на региональном уровне. Авторами проведено исследование понятия потенциал, выявлена динамическая восприимчивость выборочной совокупности ресурсов, рассмотрено трансцендентное свойство потенциала в функциональном аспекте контроллинговой деятельности предприятия. Процедура и методы. В работе сформулированы тезисы и определена алгоритмика, используемая при создании корректной инновационной стратегии регионального уровня. При проведении исследования применены методы системного анализа, коэффициентный метод, а также метод аналогии и сравнения. Результаты. В ходе работы авторами рассмотрена структура инновационной стратегии региона, кратко сформулирована и предложена группировка инновационных потенциалов: коэффициенты перспективных возможностей, результирующие и запросные инновационные коэффициенты. Теоретическая и/или практическая значимость. Авторам удалось обновить проблематику формирования механизма инновационного развития совокупного ресурсного потенциала региона.

In the present paper the crack propagation direction angles on the basis of three different fracture criteria are found. The maximum tangential stress criterion, the minimum strain energy density criterion and the deformation criterion are used and analysed. The generalized forms of these criteria have been used. It implies that the crack propagation direction angles are obtained with the Williams series expansion in which the higher order terms are kept. The calculations are performed in Waterloo Maple computer algebra software. The analysis of the crack propagation direction angles show that the influence of the higher order terms cant be ignored. The angles differ considerably when the higher order terms are taken into account.

The creep crack problems in damaged materials under mixed mode loading (Mode I and Mode II loading) in the framework of creep-damage coupled formulation are considered. The class of the self-similar solutions to the plane creep crack problems in a damaged medium under mixed-mode loading is given. With the similarity variable and the self-similar representation of the solution for a power-law creeping material and the Kachanov-Rabotnov power-law damage evolution equation the near crack-tip stresses, creep strain rates and continuity distributions for plane stress and plane strain conditions are obtained. The similarity solutions are based on the hypothesis of the existence of the completely damaged zone near the crack tip. It is shown that the asymptotic analysis of the near crack-tip fields gives rise to the nonlinear eigenvalue problems. The technique permitting to find all the eigenvalues numerically is proposed and numerical solutions of the nonlinear eigenvalue problems arising from the mixed-mode crack problems in a power-law medium under plane stress conditions are obtained. Using the approach developed the eigenvalues different from the eigenvalues corresponding to the Hutchinson-Rice-Rosengren (HRR) problem are found. The angular distributions of the stress and the continuity fields are selected as the crack tip fields of interest. Having obtained the eigenspectra and eigensolutions the geometry of the completely damaged zone in the vicinity of the crack tip is found for all values of the mixity parameter.