As one of the advanced and efficient means of joining,the clinching process is capable of joining sheets with different materials or different sheet thicknesses.In this article,a novel modified clinching process,i.e.,...As one of the advanced and efficient means of joining,the clinching process is capable of joining sheets with different materials or different sheet thicknesses.In this article,a novel modified clinching process,i.e.,the dieless clinching process,was executed to join AA6061 aluminum alloy with sheet thicknesses of 1.5,2.0,2.5 and 3.0 mm according to different sheet stack-ups.The geometrical characteristics,microhardness distribution,failure behavior,static strength,absorbed energy and instantaneous stiffness of the novel dieless joint were gotten and investigated.The results indicated that the sheet thickness ratio has a notable effect on the failure behavior and mechanical properties of the novel dieless clinched joint,and a relatively large sheet thickness ratio can improve the joint performance when joining sheets with different sheet thicknesses.展开更多
Partial transient liquid phase （PTLP） bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate ...Partial transient liquid phase （PTLP） bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885℃ under a pulsed pressure of 2-10 MPa within durations in the range of 2-8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the o- phase with a limit solubility of Nb, a sequence of Ti-Cu intermetallic phases and solid solutions of Ni and Cu in α＋β Ti in the reaction zone. The maximum shear strength of 106.7 MPa was obtained when the joint was bonded for 5 rain, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti-Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner.展开更多
The comparative research on the seismic performance of grouted sleeve connected pier(GS)and prestressed precast segmental concrete pier(PC)is mostly carried out by numerical simulation.In this study,the GS pier and th...The comparative research on the seismic performance of grouted sleeve connected pier(GS)and prestressed precast segmental concrete pier(PC)is mostly carried out by numerical simulation.In this study,the GS pier and the PC pier of the new railway project from Hetian to Ruoqiang are taken into consideration.Two kinds of 1/5-scale assembled double-column specimens are made,and the quasi-static tests are carried out.The overall seismic performance of the two spliced piers is studied,and compared in terms of failure mechanism,bearing capacity,ductility,stiffness and energy dissipation capacity.The results show that the failure modes of both GS pier and PC pier are characterized by bending.However,the specific failure location and form are different.The GS pier presents a complete hysteretic curve,large equivalent stiffness and strong energy dissipation capacity.The hysteretic area of the PC pier is small.However,it has good self-reset ability and quasi-static residual displacement.Finite element models are set up using DispBeamColumn fiber elements and ZeroLength elements.The models that are calibrated with the test data can effectively simulate the damage development under monotonic loading.The load−displacement curves are in good agreement with the backbone curves of the test results.展开更多
基金Project(51805416) supported by the National Natural Science Foundation of ChinaProject(2019QNRC001) supported by the Young Elite Scientists Sponsorship Program by CAST,China+1 种基金Project(2021JJ20059) supported by the Hunan Provincial Natural Science Foundation for Excellent Young Scholars,ChinaProject(2019RS1002) supported by the Huxiang High-Level Talent Gathering Project of Hunan Province,China。
文摘As one of the advanced and efficient means of joining,the clinching process is capable of joining sheets with different materials or different sheet thicknesses.In this article,a novel modified clinching process,i.e.,the dieless clinching process,was executed to join AA6061 aluminum alloy with sheet thicknesses of 1.5,2.0,2.5 and 3.0 mm according to different sheet stack-ups.The geometrical characteristics,microhardness distribution,failure behavior,static strength,absorbed energy and instantaneous stiffness of the novel dieless joint were gotten and investigated.The results indicated that the sheet thickness ratio has a notable effect on the failure behavior and mechanical properties of the novel dieless clinched joint,and a relatively large sheet thickness ratio can improve the joint performance when joining sheets with different sheet thicknesses.
基金Project(51421001)supported by the National Natural Science Foundation of ChinaProjects(106112015CDJXZ138803,106112015CDJXY130003)supported by the Fundamental Research Funds for the Central Universities,China
文摘Partial transient liquid phase （PTLP） bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885℃ under a pulsed pressure of 2-10 MPa within durations in the range of 2-8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the o- phase with a limit solubility of Nb, a sequence of Ti-Cu intermetallic phases and solid solutions of Ni and Cu in α＋β Ti in the reaction zone. The maximum shear strength of 106.7 MPa was obtained when the joint was bonded for 5 rain, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti-Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner.
基金Project(N2018G034)supported by China Railway Corporation。
文摘The comparative research on the seismic performance of grouted sleeve connected pier(GS)and prestressed precast segmental concrete pier(PC)is mostly carried out by numerical simulation.In this study,the GS pier and the PC pier of the new railway project from Hetian to Ruoqiang are taken into consideration.Two kinds of 1/5-scale assembled double-column specimens are made,and the quasi-static tests are carried out.The overall seismic performance of the two spliced piers is studied,and compared in terms of failure mechanism,bearing capacity,ductility,stiffness and energy dissipation capacity.The results show that the failure modes of both GS pier and PC pier are characterized by bending.However,the specific failure location and form are different.The GS pier presents a complete hysteretic curve,large equivalent stiffness and strong energy dissipation capacity.The hysteretic area of the PC pier is small.However,it has good self-reset ability and quasi-static residual displacement.Finite element models are set up using DispBeamColumn fiber elements and ZeroLength elements.The models that are calibrated with the test data can effectively simulate the damage development under monotonic loading.The load−displacement curves are in good agreement with the backbone curves of the test results.
