We present a new test method for the accurate measurement of the transverse tensile interfacial strength of rare-earth barium copper oxide(REBCO)-coated conductor(CC)tapes to overcome heavy scattering of data tested u...We present a new test method for the accurate measurement of the transverse tensile interfacial strength of rare-earth barium copper oxide(REBCO)-coated conductor(CC)tapes to overcome heavy scattering of data tested using regular test methods.A new composite structure specimen is designed and constructed by solidifying a standard epoxy resin tensile specimen using the three-dimensional printing technology,where a short REBCO CC tape is embedded.The feasibility of the proposed test method is numerically validated through finite element(FE)calculations.Experimental results show that the valid delaminated strength is 2.19-2.51 MPa with the maximum relative error of 7.3%,indicating the elimination of significant scattering in the tested data.By analysing the morphology of the delaminated interfaces and energy-dispersive spectroscopy results,it is discovered that delamination primarily occurs at the interface between the REBCO superconducting layer and the buffer layer and that a small portion of the REBCO and buffer layers peels off.Further error analysis based on the FE method indicates that the tape is more likely to delaminate because of initial defects,whereas the adhesion at the edges of the CC tape due to the redundancy of the epoxy resin increases the resistance of the CC tape to delamination,resulting in a higher testing value than the real one.展开更多
The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Eff...The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow ex-pansion and compression on the cellular detonation cell were investigated to illus-trate the mechanism of the transverse wave development and the cellular detona-tion cell evolution. By examining gas composition variations behind the leading shock,the chemical reaction rate,the reaction zone length,and thermodynamic parameters,two kinds of the abnormal detonation waves were identified. To explore their development mechanism,chemical reactions,reflected shocks and rarefac-tion waves were discussed,which interact with each other and affect the cellular detonation in different ways.展开更多
Fatigue crack growth(FCG)behavior of 9 Cr/CrMoV dissimilar welded joint at elevated temperature and different stress ratios was investigated.Attention was paid to the region near the fusion line of 9 Cr where carbon-e...Fatigue crack growth(FCG)behavior of 9 Cr/CrMoV dissimilar welded joint at elevated temperature and different stress ratios was investigated.Attention was paid to the region near the fusion line of 9 Cr where carbon-enriched zone(CEZ)and carbon-depleted zone(CDZ)formed due to carbon migration during the welding process.Hard and brittle tempered martensite dominated the stress ratio-insensitive FCG behavior in the coarse grain zone(CGZ)of 9 Cr-HAZ.For crack near the CGZ-CEZ interface,crack deflection through the CEZ and into the CDZ was observed,accompanied by an accelerating FCG rate.Compared with the severe plastic deformation near the secondary crack in 9 Cr-CGZ,the electron back-scattered diffraction analysis showed less deformation and lower resistance in the direction toward the brittle CEZ,which resulted in the transverse deflection.In spite of the plastic feature in CDZ revealed by fracture morphology,the less carbides due to carbon migration led to lower strength and weaker FCG resistance property in this region.In conclusion,the plasticity deterioration in CEZ and strength loss in CDZ accounted for the FCG path deflection and FCG rate acceleration,respectively,which aggravated the worst FCG resistance property of 9 Cr-HAZ in the dissimilar welded joint.展开更多
The map expression of ＂abrupt＂ changes in lateral stratigraphic level of a thrust fault has been traditionally interpreted to be a result of the presence of （1） a lateral （or oblique） thrust-ramp, or （2） a fro...The map expression of ＂abrupt＂ changes in lateral stratigraphic level of a thrust fault has been traditionally interpreted to be a result of the presence of （1） a lateral （or oblique） thrust-ramp, or （2） a frontal ramp with displacement gradient, and/or （3） a combination of these geometries. These geometries have been used to interpret the structures near transverse zones in fold-thrust belts （FTB）. This contribution outlines an alternative explanation that can result in the same map pattern by lateral variations in stratigraphy along the strike of a low angle thrust fault. We describe the natural example of the Leamington transverse zone, which marks the southern margin of the Pennsylvanian-Permian Oquirrh basin with genetically related lateral stratigraphic variations in the North American Sevier FTB. Thus, the observed map pattern at this zone is closely related to lateral stratigraphic variations along the strike of a horizontal fault. Even though the present-day erosional level shows the map pattern that could be interpreted as a lateral ramp, the observed structures along the Leamington zone most likely share the effects of the presence of a lateral （or oblique） ramp, lateral stratigraphic variations along the fault trace, and the displacement gradient.展开更多
基金the National Natural Science Foundation of China(11902129,11932008)the China Postdoctoral Science Foundation(2019T120963)the Fundamental Research Funds for the Central Universities(lzujbky-2020-pd03,lzujbky-2021-kb06).
文摘We present a new test method for the accurate measurement of the transverse tensile interfacial strength of rare-earth barium copper oxide(REBCO)-coated conductor(CC)tapes to overcome heavy scattering of data tested using regular test methods.A new composite structure specimen is designed and constructed by solidifying a standard epoxy resin tensile specimen using the three-dimensional printing technology,where a short REBCO CC tape is embedded.The feasibility of the proposed test method is numerically validated through finite element(FE)calculations.Experimental results show that the valid delaminated strength is 2.19-2.51 MPa with the maximum relative error of 7.3%,indicating the elimination of significant scattering in the tested data.By analysing the morphology of the delaminated interfaces and energy-dispersive spectroscopy results,it is discovered that delamination primarily occurs at the interface between the REBCO superconducting layer and the buffer layer and that a small portion of the REBCO and buffer layers peels off.Further error analysis based on the FE method indicates that the tape is more likely to delaminate because of initial defects,whereas the adhesion at the edges of the CC tape due to the redundancy of the epoxy resin increases the resistance of the CC tape to delamination,resulting in a higher testing value than the real one.
文摘The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow ex-pansion and compression on the cellular detonation cell were investigated to illus-trate the mechanism of the transverse wave development and the cellular detona-tion cell evolution. By examining gas composition variations behind the leading shock,the chemical reaction rate,the reaction zone length,and thermodynamic parameters,two kinds of the abnormal detonation waves were identified. To explore their development mechanism,chemical reactions,reflected shocks and rarefac-tion waves were discussed,which interact with each other and affect the cellular detonation in different ways.
基金financial support by the National Natural Science Foundation of China(No.52001200)the experimental support by Instrumental Analysis Center of SJTU。
文摘Fatigue crack growth(FCG)behavior of 9 Cr/CrMoV dissimilar welded joint at elevated temperature and different stress ratios was investigated.Attention was paid to the region near the fusion line of 9 Cr where carbon-enriched zone(CEZ)and carbon-depleted zone(CDZ)formed due to carbon migration during the welding process.Hard and brittle tempered martensite dominated the stress ratio-insensitive FCG behavior in the coarse grain zone(CGZ)of 9 Cr-HAZ.For crack near the CGZ-CEZ interface,crack deflection through the CEZ and into the CDZ was observed,accompanied by an accelerating FCG rate.Compared with the severe plastic deformation near the secondary crack in 9 Cr-CGZ,the electron back-scattered diffraction analysis showed less deformation and lower resistance in the direction toward the brittle CEZ,which resulted in the transverse deflection.In spite of the plastic feature in CDZ revealed by fracture morphology,the less carbides due to carbon migration led to lower strength and weaker FCG resistance property in this region.In conclusion,the plasticity deterioration in CEZ and strength loss in CDZ accounted for the FCG path deflection and FCG rate acceleration,respectively,which aggravated the worst FCG resistance property of 9 Cr-HAZ in the dissimilar welded joint.
基金supported by MLTM of Korean Government Program 20052004 to S.Kwon
文摘The map expression of ＂abrupt＂ changes in lateral stratigraphic level of a thrust fault has been traditionally interpreted to be a result of the presence of （1） a lateral （or oblique） thrust-ramp, or （2） a frontal ramp with displacement gradient, and/or （3） a combination of these geometries. These geometries have been used to interpret the structures near transverse zones in fold-thrust belts （FTB）. This contribution outlines an alternative explanation that can result in the same map pattern by lateral variations in stratigraphy along the strike of a low angle thrust fault. We describe the natural example of the Leamington transverse zone, which marks the southern margin of the Pennsylvanian-Permian Oquirrh basin with genetically related lateral stratigraphic variations in the North American Sevier FTB. Thus, the observed map pattern at this zone is closely related to lateral stratigraphic variations along the strike of a horizontal fault. Even though the present-day erosional level shows the map pattern that could be interpreted as a lateral ramp, the observed structures along the Leamington zone most likely share the effects of the presence of a lateral （or oblique） ramp, lateral stratigraphic variations along the fault trace, and the displacement gradient.
