This work used a modified direct shear apparatus, created newly by the authors, to explore effects of the gap between shear box halves and specimen size on the shear resistance of coarse-grained soil. The shear boxes ...This work used a modified direct shear apparatus, created newly by the authors, to explore effects of the gap between shear box halves and specimen size on the shear resistance of coarse-grained soil. The shear boxes of this apparatus were assembled from a series of steel structures capable of superimposition and nesting. Such characteristics facilitated variation of specimen size in both diameter and height. The new device can also maintain a constant gap during shearing. We performed a series of gap-effect and size-effect tests for two uniformly graded, coarse^grained soil samples. The test results showed that both the gap space and specimen size bad significant influences on shear resistance of the coarse-grained soil. Further, analysis of variations in shear strength indices led to a reasonable gap dimension and specimen size of the two soil samples.展开更多
In underwater applications of contactless power transmission(CLPT) systems,high pressure and noncoaxial operations will change the parameters of electromagnetic(EM) couplers.As a result,the system will divert from its...In underwater applications of contactless power transmission(CLPT) systems,high pressure and noncoaxial operations will change the parameters of electromagnetic(EM) couplers.As a result,the system will divert from its optimum performance.Using a reluctance modeling method,we investigated the gap effects on the EM coupler in deep-sea environment.Calculations and measurements were performed to analyze the influence of high pressure and noncoaxial alignments on the coupler.It was shown that it is useful to set a relatively large gap between cores to reduce the influence of pressure.Experiments were carried out to verify the transferring capacity of the designed coupler and system for a fixed frequency.The results showed that an EM coupler with a large gap can serve a stable and efficient power transmission for the CLPT system.The designed system can transfer more than 400 W electrical power with a 2-mm gap in the EM coupler,and the efficiency was up to 90% coaxially and 87% non-coaxially in 40 MPa salt water.Finally,a mechanical layout of a 400 W EM coupler for the underwater application in 4000-m deep sea was proposed.展开更多
文摘This work used a modified direct shear apparatus, created newly by the authors, to explore effects of the gap between shear box halves and specimen size on the shear resistance of coarse-grained soil. The shear boxes of this apparatus were assembled from a series of steel structures capable of superimposition and nesting. Such characteristics facilitated variation of specimen size in both diameter and height. The new device can also maintain a constant gap during shearing. We performed a series of gap-effect and size-effect tests for two uniformly graded, coarse^grained soil samples. The test results showed that both the gap space and specimen size bad significant influences on shear resistance of the coarse-grained soil. Further, analysis of variations in shear strength indices led to a reasonable gap dimension and specimen size of the two soil samples.
基金supported by the National High-Tech R & D Program (863) of China (No 2007AA091201)the Natural Science Foundation of Zhejiang Province, China (No Y5090117)the Qianjiang Excellence Project of Zhejiang Province, China (No 2009R10036)
文摘In underwater applications of contactless power transmission(CLPT) systems,high pressure and noncoaxial operations will change the parameters of electromagnetic(EM) couplers.As a result,the system will divert from its optimum performance.Using a reluctance modeling method,we investigated the gap effects on the EM coupler in deep-sea environment.Calculations and measurements were performed to analyze the influence of high pressure and noncoaxial alignments on the coupler.It was shown that it is useful to set a relatively large gap between cores to reduce the influence of pressure.Experiments were carried out to verify the transferring capacity of the designed coupler and system for a fixed frequency.The results showed that an EM coupler with a large gap can serve a stable and efficient power transmission for the CLPT system.The designed system can transfer more than 400 W electrical power with a 2-mm gap in the EM coupler,and the efficiency was up to 90% coaxially and 87% non-coaxially in 40 MPa salt water.Finally,a mechanical layout of a 400 W EM coupler for the underwater application in 4000-m deep sea was proposed.
