Papers by Keyword: Transverse Crack

Abstract: The breathing mechanism of a transverse crack in an elastic shaft has been extensively researched. Although many different crack models have been presented, little published research has explored experimentally how the shaft crack breathing mechanism interacts with the change of stiffness during each revolution. This study addressed static analysis of the stiffness of elastic shafts with experimentally-induced fatigue, welding or wire cut transverse cracks. Bending stiffness was measured from different angles under a three point bending fixture, to efficiently define the correct periodical stiffness variation for different crack types. The opening and closing of each crack (breathing effect) were investigated for their association with shaft stiffness. It was found that width of the crack opening gap is a crucial factor which influences the crack breathing behaviour. Experimental results are expected to assist with crack diagnosis.

Abstract: This systematic study of the red mud dam and the formation of cracks in the mechanism, and summarize a variety of cracks in the dam prevention and treatment methods. According to the second red mud dam cracks In shandong aluminum company,the detailed analysis of its causes, and take the excavation backfilling, grouting and other measures to crack effect is obvious in time, eliminating the risks of dam, the dam will be more stable, have run more secure.

Abstract: The transverse crack, which is the most dangerous damage among the various types of rail defects, is developed from shelling near the rail running face, and grows perpendicular to the rail surface. Therefore, to assure the safety of rolling stocks, it is necessary to investigate the fatigue crack growth behavior of a gas pressure welded part of rail steel under mode I and mixed mode loadings. In this study, the fatigue crack growth behavior under the mixed mode was discussed by using comparative stress intensity factor ranges proposed by Richard. In addition, to evaluate the effect of the crack closure quantitatively, the crack opening load was determined a using clip-on gauge and computerized image processing system. As a result of this, a mixed mode crack growth rate regardless of the stress ratio could be correlated with the effective comparative stress intensity factor ranges derived from the crack opening loading.

Abstract: Understanding dynamic behavior of a rotor system with a transverse crack is of great significance for operation reliability of rotating machinery. The transfer matrix method is widely used for rotor dynamic analysis, but it encounters difficulties modeling a crack. This study proposes a finite-width crack model that simulates the local stiffness reduction effect of a gaping crack in transfer matrix method. This model is obtained by comparing finite element analysis results of a shaft with a zero-width crack and its counterpart transfer matrix calculation results with a trial equivalent finite-width slot. Different shaft geometry and loading modes are considered to improve the generality of the model. An application example is given that uses the proposed model to calculate critical speeds of a multi-disk rotor system with a transverse crack at different positions.

Abstract: When stress is high, delaminate damage can be induced by transverse cracks. A complete parabolic shear-lag damage model containing delamination induced by transverse cracks is therefore proposed and applied to predict the stiffness reduction by transverse cracking in cross-ply laminated composite materials. The predictions of the complete parabolic shear-lag analysis model, the incomplete parabolic shear-lag analysis model, and the complete parabolic shear-lag damage model containing delamination proposed in this paper have been compared. Results show that the young’s modulus reduction values obtained by our analysis model are better agreement with the experimental ones than other models.