On the basis of these data, the main factors affecting the crack openings are found according to the basic principles on the emergence and development of cracks.

Comparing the behavior of the equally sized crack openings occured in the welded joint with that in the parent metal, the possibility of applying the test results obtained from the parent metal to the welded joint was investigated and an empirical formula was suggested, by which the tolerable surface crack size in the high strained rigion of a pressure vossel may be calculated.

This paper analyzes the crack closure phenomenon caused by the fatigue crack plasticity at precracks. The stress intensity factor of crack openings can be represented approximately as a function of the load stress and the amount of crack extension.

As previously reported for Stage II cracking in Al 2219-T851, residual crack openings are observed for zero load which can be empirically related to the crack closure stress.

This relationship holds regardless of the ambient humidity during fatigue, although there are significant changes in the zero load crack openings developed with humidity.

The present interpretation of the phenomenon is that the residual crack openings are indirectly related to the crack closure load associated with the microcracks.

For a fixed crack length the residual crack openings are found to be largest if the relative humidity is low or if the crack path is particularly irregular.

The magnitude of such residual crack openings measured at the test specimen surface is determined as a function of the crack length and the relative humidity in which the specimens were fatigued.

Experimental procedures and data on the crack openings in R.C. Members with circular (annular) cross sections are introduced in this paper. On the basis of these data, the main factors affecting the crack openings are found according to the basic principles on the emergence and development of cracks. Through statistic analysis, a practical formula for calculating the crack width in R.C. members with circular (annular) cross sections under eccentric compression is established, with a reliability...

Experimental procedures and data on the crack openings in R.C. Members with circular (annular) cross sections are introduced in this paper. On the basis of these data, the main factors affecting the crack openings are found according to the basic principles on the emergence and development of cracks. Through statistic analysis, a practical formula for calculating the crack width in R.C. members with circular (annular) cross sections under eccentric compression is established, with a reliability of 95% and a mean square deviation (also coefficient of variation) of 20% for the ratio between the experimental and theoreticl results. The proposed formula is clear in conception, simple and convenient for calculation purposes and the results are fairly close to those obtained from experiments.

Surface crack is one of the most common flaws occured in the welded pressure vessels. In order to obtain the best economical benefit in the control and repair of a welded pressure vessel, it is necessary to have a standard suitable for predicting the crack tolerance. In this paper, a criterion of COD was employed. By using of a lots of small wide-plate tensile tests through orthogonal experimental design and the application of the orthogonal polynomial expansion method to the factorial effect function, a functional...

Surface crack is one of the most common flaws occured in the welded pressure vessels. In order to obtain the best economical benefit in the control and repair of a welded pressure vessel, it is necessary to have a standard suitable for predicting the crack tolerance. In this paper, a criterion of COD was employed. By using of a lots of small wide-plate tensile tests through orthogonal experimental design and the application of the orthogonal polynomial expansion method to the factorial effect function, a functional relationship was obtained between the surface crack opening displacement and the geometric crack size as well as the stress level exsisted. Comparing the behavior of the equally sized crack openings occured in the welded joint with that in the parent metal, the possibility of applying the test results obtained from the parent metal to the welded joint was investigated and an empirical formula was suggested, by which the tolerable surface crack size in the high strained rigion of a pressure vossel may be calculated.

In order to guarantee the safety of TGPs permanent shiplocks excavated high slope during the construction and operation period, from the beginning of construction in April, 1994, comparatively complete monitoring items and facilities have been installed. The analysis on the monitored data demonstrates that the slope is stable in whole. The major failure mode of the slope is the local rock block lossing stability, and after taking suitable strengthening countermeasures, the slope stability can be reached. Some...

In order to guarantee the safety of TGPs permanent shiplocks excavated high slope during the construction and operation period, from the beginning of construction in April, 1994, comparatively complete monitoring items and facilities have been installed. The analysis on the monitored data demonstrates that the slope is stable in whole. The major failure mode of the slope is the local rock block lossing stability, and after taking suitable strengthening countermeasures, the slope stability can be reached. Some cracks occurred and developed for a time on the top of rock central wall between locks from second lock chamber to third lock chamber. The crack openings assumed an obvious shrinkage trend along with the termination of chamber excavation. The time effect deformation value of the rock mass is small and the duration is short. It is predicted that the deformation of the rock slope will not influence the normal operation of the shiplocks mitre gate.