Characteristic measurement of contact discharge currents are made through a hand-held metal rod from charged human body. Correlation coefficients are obtained, through Statistic Package for Social Science (SPSS), for ...Characteristic measurement of contact discharge currents are made through a hand-held metal rod from charged human body. Correlation coefficients are obtained, through Statistic Package for Social Science (SPSS), for various charge voltages, which is based on the effect test of electrode contact approach speeds on discharge current parameters of current peaks, maximum rising slope and spark lengths. Discharge parameters at charge voltage 300V are independent on approach speed. For charge voltages equal to and higher than 500V, the contact approach speed has strong positive cor- relation with discharge parameters of the peak current and the maximum rising slope, whereas has strong negative correlation with the spark length.展开更多
In this study, two different designs of liquid metal fast reactor(LMFR) fuel rods wire-wrapped and nonwire-wrapped(bare) are compared with respect to different parameters as a means of considering the optimum fuel des...In this study, two different designs of liquid metal fast reactor(LMFR) fuel rods wire-wrapped and nonwire-wrapped(bare) are compared with respect to different parameters as a means of considering the optimum fuel design. Nuclear seismic rules require that systems and components that are important for safety must be capable of bearing earthquake effects, and that their integrity and functionality should be guaranteed. Mode shapes, natural frequencies, stresses on cladding, and seismic aspects are considered for comparison using ANSYS. Modal analysis is compared in a vacuum and in lead–bismuth eutectic(LBE) using potential flow theory by considering the added mass effect. A simple and accurate approach is suggested for the determination of the LBE added mass effect and is verified by a manually calculated added mass, which further proved the usefulness of potential flow theory for the accurate estimation of the added mass effect. The verification of the hydrodynamic function(τ) over the entire frequency range further validated the finite element method(FEM) modal analysis results. Stresses obtained for fuel rods against different loading combinations revealed that they were within the allowable limits with maximum stress ratios of 0.25(bare) and 0.74(wire-wrapped). In order to verify the structural integrity of cladding tubes, stresses along the cladding length were determined during different transients and were also calculated manually for static pressure. The manual calculations could be roughly compared with the ANSYS results, and the two showed a close agreement. Contact analysis methodology was selected,and the most appropriate analysis options were suggested for establishing contact between the wire and cladding for the wire-wrapped design grid independence analysis,which proved the accuracy of the results, confirmed the selection of the appropriate procedure, and validated the use of the ANSYS mechanical APDL code for LMFR fuel rod analysis. The results provided detailed insight into the structural design of LMFR fuel rods by considering different structural configurations(i.e., bare and wire-wrapped) in the seismic loading;this not only provides a FEM procedure for LMFR fuel with complex configuration, but also guides the reference design of LMFR fuel rods.展开更多
Taizhou Bridge is a suspension bridge with three pylons and two 1 080 m main spans. The middle pylon is a steel frame with longitudinal herringbone shape and lateral gate shape. The connection between steel pylon and ...Taizhou Bridge is a suspension bridge with three pylons and two 1 080 m main spans. The middle pylon is a steel frame with longitudinal herringbone shape and lateral gate shape. The connection between steel pylon and concrete pile cap is a key part to transfer the huge inner force from the pylon to the foundation. Its construction quality is a critical factor to the overall structural loading of the whole bridge; therefore the contact ratio between the bearing steel plate of pylon and concrete pile cap is required to be over 75 %. The inclined joint surface in two directions, longitudinally at 39/1 920 and laterally at 1/4, posted a challenge to the construction work. A procedure test was carried out to find an optimal construction method by comparison, and finally the post-injection method was selected as it can meet the requirement of concrete strength and contact ratio at the connection. The successful application of the post-injection method in Taizhou Bridge can provide an example and reference for similar projects in the future.展开更多
基金Supported by the National Natural Science Foundation of China (No.60473021)
文摘Characteristic measurement of contact discharge currents are made through a hand-held metal rod from charged human body. Correlation coefficients are obtained, through Statistic Package for Social Science (SPSS), for various charge voltages, which is based on the effect test of electrode contact approach speeds on discharge current parameters of current peaks, maximum rising slope and spark lengths. Discharge parameters at charge voltage 300V are independent on approach speed. For charge voltages equal to and higher than 500V, the contact approach speed has strong positive cor- relation with discharge parameters of the peak current and the maximum rising slope, whereas has strong negative correlation with the spark length.
基金supported by the National Key R&D Program of China(No.2018YFB1900601)National Natural Science Foundation of China(No.11772086)
文摘In this study, two different designs of liquid metal fast reactor(LMFR) fuel rods wire-wrapped and nonwire-wrapped(bare) are compared with respect to different parameters as a means of considering the optimum fuel design. Nuclear seismic rules require that systems and components that are important for safety must be capable of bearing earthquake effects, and that their integrity and functionality should be guaranteed. Mode shapes, natural frequencies, stresses on cladding, and seismic aspects are considered for comparison using ANSYS. Modal analysis is compared in a vacuum and in lead–bismuth eutectic(LBE) using potential flow theory by considering the added mass effect. A simple and accurate approach is suggested for the determination of the LBE added mass effect and is verified by a manually calculated added mass, which further proved the usefulness of potential flow theory for the accurate estimation of the added mass effect. The verification of the hydrodynamic function(τ) over the entire frequency range further validated the finite element method(FEM) modal analysis results. Stresses obtained for fuel rods against different loading combinations revealed that they were within the allowable limits with maximum stress ratios of 0.25(bare) and 0.74(wire-wrapped). In order to verify the structural integrity of cladding tubes, stresses along the cladding length were determined during different transients and were also calculated manually for static pressure. The manual calculations could be roughly compared with the ANSYS results, and the two showed a close agreement. Contact analysis methodology was selected,and the most appropriate analysis options were suggested for establishing contact between the wire and cladding for the wire-wrapped design grid independence analysis,which proved the accuracy of the results, confirmed the selection of the appropriate procedure, and validated the use of the ANSYS mechanical APDL code for LMFR fuel rod analysis. The results provided detailed insight into the structural design of LMFR fuel rods by considering different structural configurations(i.e., bare and wire-wrapped) in the seismic loading;this not only provides a FEM procedure for LMFR fuel with complex configuration, but also guides the reference design of LMFR fuel rods.
基金National Science and Technology Support Program of China(No.2009BAG15B02)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-180)
文摘Taizhou Bridge is a suspension bridge with three pylons and two 1 080 m main spans. The middle pylon is a steel frame with longitudinal herringbone shape and lateral gate shape. The connection between steel pylon and concrete pile cap is a key part to transfer the huge inner force from the pylon to the foundation. Its construction quality is a critical factor to the overall structural loading of the whole bridge; therefore the contact ratio between the bearing steel plate of pylon and concrete pile cap is required to be over 75 %. The inclined joint surface in two directions, longitudinally at 39/1 920 and laterally at 1/4, posted a challenge to the construction work. A procedure test was carried out to find an optimal construction method by comparison, and finally the post-injection method was selected as it can meet the requirement of concrete strength and contact ratio at the connection. The successful application of the post-injection method in Taizhou Bridge can provide an example and reference for similar projects in the future.
