In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for weld...In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for welded joints of arch-ribbed steel tubes using 7-,8-and 9-layer welds is carried out and its accuracy is demonstrated.The steel pipe welding temperature changes,residual stress distribution,different processes residual stress changes in the law,the prediction of post-weld residual stress distribution and deformation are studied in this paper.The results show that the temperature field values and test results are more consistent with the accuracy of numerical simulation of welding,the welding process is mainly in the form of heat transfer;Residual high stresses are predominantly distributed in the Fusion zone(FZ)and Heat-affected zone(HAZ),with residual stress levels tending to decrease from the center of the weld along the axial path,the maximum stress appears in the FZ and HAZ junction;The number of welding layers has an effect on the residual stress distribution,the number of welding layers increases,the residual stress tends to decrease,while the FZ and HAZ high stress area range shrinks;Increasing the number of plies will increase the amount of residual distortion.展开更多
The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage den...The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO_(3)- xNaTaO_(3) ceramics, by building a new phase boundary. As a result, a high recoverable energy density(Wrec) of 2.2 J/cm3 and efficiency (h) of 80.1% were achieved in 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic at300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectricphase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio ofantiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic also exhibitedgood temperature and frequency stability, together with excellent charge-discharge performance. Theresults pave a good way of designing new NaNbO_(3)-based antiferroelectrics with good energy storageperformance.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.52268048)the Guangxi Key Technology Research and Development Program(Grant No.GUI-KEAB23026101)the Guangxi Science and Technology Major Special Project(Grant No.GUI-KEAA22068066).
文摘In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for welded joints of arch-ribbed steel tubes using 7-,8-and 9-layer welds is carried out and its accuracy is demonstrated.The steel pipe welding temperature changes,residual stress distribution,different processes residual stress changes in the law,the prediction of post-weld residual stress distribution and deformation are studied in this paper.The results show that the temperature field values and test results are more consistent with the accuracy of numerical simulation of welding,the welding process is mainly in the form of heat transfer;Residual high stresses are predominantly distributed in the Fusion zone(FZ)and Heat-affected zone(HAZ),with residual stress levels tending to decrease from the center of the weld along the axial path,the maximum stress appears in the FZ and HAZ junction;The number of welding layers has an effect on the residual stress distribution,the number of welding layers increases,the residual stress tends to decrease,while the FZ and HAZ high stress area range shrinks;Increasing the number of plies will increase the amount of residual distortion.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11864004 and 52072080)The author also thanks to the fund(Grant No.20KF-16)from the Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices,Guilin University of Technology,Guilin(541004),China.
文摘The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO_(3)- xNaTaO_(3) ceramics, by building a new phase boundary. As a result, a high recoverable energy density(Wrec) of 2.2 J/cm3 and efficiency (h) of 80.1% were achieved in 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic at300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectricphase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio ofantiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic also exhibitedgood temperature and frequency stability, together with excellent charge-discharge performance. Theresults pave a good way of designing new NaNbO_(3)-based antiferroelectrics with good energy storageperformance.
