In order to analyze the welding thermal characteristics problem,the multiscale finite element(FE)model of T-shape thin-wall assembly structure for different thicknesses and the heat source model are established to emp...In order to analyze the welding thermal characteristics problem,the multiscale finite element(FE)model of T-shape thin-wall assembly structure for different thicknesses and the heat source model are established to emphatically study their welding temperature distributions under different conditions.Simultaneously,different welding technology parameters and welding directions are taken into account,and the fillet weld for different welding parameters is employed on the thin-wall parts.Through comparison analysis,the results show that different welding directions,welding thicknesses and welding heat source parameters have a certain impact on the temperature distribution.Meanwhile,for the thin-wall assembly structure of the same thickness,when the heat source is moving,the greater the moving speed,the smaller the heating area,and the highest temperature will decrease.Therefore,the welding temperature field distribution can be altered by adjusting welding parameters,heat source parameters,welding thickness and welding direction,which is conducive to reducing welding deformation and choosing an appropriate and optimal welding thickness of thin-wall parts and relative welding process parameters,thus improving thin-wall welding structure assembly precision in the actual large-size welding structure assembly process in future.展开更多
The finite element(FE)-based simulation of welding characteristics was carried out to explore the relationship among welding assembly properties for the parallel T-shaped thin-walled parts of an antenna structure.The ...The finite element(FE)-based simulation of welding characteristics was carried out to explore the relationship among welding assembly properties for the parallel T-shaped thin-walled parts of an antenna structure.The effects of welding direction,clamping,fixture release time,fixed constraints,and welding sequences on these properties were analyzed,and the mapping relationship among welding characteristics was thoroughly examined.Different machine learning algorithms,including the generalized regression neural network(GRNN),wavelet neural network(WNN),and fuzzy neural network(FNN),are used to predict the multiple welding properties of thin-walled parts to mirror their variation trend and verify the correctness of the mapping relationship.Compared with those from GRNN and WNN,the maximum mean relative errors for the predicted values of deformation,temperature,and residual stress with FNN were less than 4.8%,1.4%,and 4.4%,respectively.These results indicate that FNN generated the best predicted welding characteristics.Analysis under various welding conditions also shows a mapping relationship among welding deformation,temperature,and residual stress over a period of time.This finding further provides a paramount basis for the control of welding assembly errors of an antenna structure in the future.展开更多
Based on full scale model of 1-beam and end-plate welding assembly with medium plate, welding temperature field and residual stress were simulated, infrared thermometers were employed to measure the real-time temperat...Based on full scale model of 1-beam and end-plate welding assembly with medium plate, welding temperature field and residual stress were simulated, infrared thermometers were employed to measure the real-time temperature Jbr verification purposes. Results show that the measured thermal cycle curves match well with the simulation result. Simulation results of welding residual stress indicate that the values of longitudinal and transverse stress on the upper surface of the plate are higher than the normal stress; higher tensile stresses exist at the end of the web weld toes and in the central area of the flange weld toes. The dangerous zones are located at the central areas of weld toes of the flange welds and near weld toes of the web welds.展开更多
Two types of automatic systems.for assembly welding. Santana automobile muffler in mass production are suggested in this paper Such systems were aPPlied to manufacture at the beginning of 1995, and were approved to ha...Two types of automatic systems.for assembly welding. Santana automobile muffler in mass production are suggested in this paper Such systems were aPPlied to manufacture at the beginning of 1995, and were approved to have high productivity and quality but low cost. It is an optimal selection for someone who manufacture automobile muffler or Similar productlons.展开更多
Multifunctional flexible sensors as wearable electronic systems have attracted considerable attention for mimicking human skin to sense ambient stimuli.However,sensors need to have high resolution,stability and sensit...Multifunctional flexible sensors as wearable electronic systems have attracted considerable attention for mimicking human skin to sense ambient stimuli.However,sensors need to have high resolution,stability and sensitivity to realize fully biomimetic skin.Here,an assembled and welded Ag/W composite nanowire flexible electrode was prepared for body motion monitoring and flexible heaters.This Ag/W composite nanowire flexible electrode has a high transmittance of 90.1%(at 121Ω·sq^(−1) sheet resistance)and a low sheet resistance of 27Ω·sq^(−1)(at 60.1%transmittance).Although the transparency of this electrode is not high,the fluctuation in relative resistance change rate at 10%strain is only 5%after 1000 tensile cycles.It can be employed to monitor human body motions,including bending of fingers,arms,wrists,and throat action.Meanwhile,the Ag/W nanowires composite film heater achieves a steady-state temperature of up to 100℃ at a constant voltage of 3.5 V and an instantaneous heating rate of up to 36.5℃·s^(−1).展开更多
There are many welding fixture layout design problems of flexible parts inbody-in-white assembly process, which directly cause body assemble variation. The fixture layoutdesign quality is mainly influenced by the posi...There are many welding fixture layout design problems of flexible parts inbody-in-white assembly process, which directly cause body assemble variation. The fixture layoutdesign quality is mainly influenced by the position and quantity of fixture locators and clamps. Ageneral analysis model of flexible assembles deformation caused by fixture is set up based on'N-2-l' locating principle, in which the locator and damper are treated as the same fixture layoutelements. An analysis model for the flexible part deformation in fixturing is set up in order toobtain the optimization object function and constraints accordingly. The final fixture elementlayout could be obtained through global optimal research by using improved genetic algorithm, whicheffectively decreases fixture elements layout influence on flexible assembles deformation.展开更多
The level of automation in the manufacture of recreational aluminum boats is very low. Robotized welding is rarely utilized, although it is commonly considered as the most effective way to reduce costs and increase co...The level of automation in the manufacture of recreational aluminum boats is very low. Robotized welding is rarely utilized, although it is commonly considered as the most effective way to reduce costs and increase competitiveness. A reason for the under-exploitation of robotics can be found in the construction of aluminum boats;boat models and their detailed structures are almost without exception individual pieces. A new stiffener structure for an aluminum recreational boat hull is developed in this work. Construction of the stiffener as a module allows exploitation of the advantages of modularization. The number of different parts is reduced and the structure simplified improves the applicability of robotic welding and provides benefits accruing from mass production. The same module can be used in several boat models. The modularity also makes it possible to use the same advanced robot welding fixture for a variety of boat models.展开更多
A new radial friction welding technology of 30 mm shell's band is introduced.Bands are assembled to shell bodies without notches by using the process.The width of heat-affected zone(HAZ) is small,and the microstru...A new radial friction welding technology of 30 mm shell's band is introduced.Bands are assembled to shell bodies without notches by using the process.The width of heat-affected zone(HAZ) is small,and the microstructure on steel side is incomplete quenching while that on cooper side is grain refining.The shear-strength of joint exceeds 200 MPa.The result of firing test indicates that radial friction welding can satisfy the assembly requirements of shell bands.展开更多
The ultrasonic welding process for wires is being largely used on industry mainly on applications that involve the connectionbetween similar or different metals. The biggest benefit of this technology is the possibili...The ultrasonic welding process for wires is being largely used on industry mainly on applications that involve the connectionbetween similar or different metals. The biggest benefit of this technology is the possibility to perform the weld without additionmaterials, like terminals, metal rings or tapes. Manufacturing of wiring harnesses demands a significant amount of joining, such aswelding, crimping or soldering, to fulfill the desired layout of the harnesses and capacity requirements, but conventional connectionprocesses, face difficulties in joining multiple cross sections mainly due to the characteristics of the processes and equipment in use.Ultrasonic metal welding process overcomes these issues due to the solid-state characteristics inherent to the process itself that includethe excellent electrical properties of the joint. Several researches on ultrasonic metal welding are being done to define the fundamentalmechanisms behind this process and it is being seen that they are completely dependent on the cross section to be welded. With thisresearch we are trying to develop methods for process characterization and define acceptable quality parameters in this process. Themain topics addressed in this paper are the characterization the weld formation using copper-to-copper wires using optical microscopyand the analysis of insulation material when submitted to different thermal conditions.展开更多
基金The National Natural Science Foundation of China(No.51675100)the National Numerical Control Equipment Major Project of China(o.2016ZX04004008)
文摘In order to analyze the welding thermal characteristics problem,the multiscale finite element(FE)model of T-shape thin-wall assembly structure for different thicknesses and the heat source model are established to emphatically study their welding temperature distributions under different conditions.Simultaneously,different welding technology parameters and welding directions are taken into account,and the fillet weld for different welding parameters is employed on the thin-wall parts.Through comparison analysis,the results show that different welding directions,welding thicknesses and welding heat source parameters have a certain impact on the temperature distribution.Meanwhile,for the thin-wall assembly structure of the same thickness,when the heat source is moving,the greater the moving speed,the smaller the heating area,and the highest temperature will decrease.Therefore,the welding temperature field distribution can be altered by adjusting welding parameters,heat source parameters,welding thickness and welding direction,which is conducive to reducing welding deformation and choosing an appropriate and optimal welding thickness of thin-wall parts and relative welding process parameters,thus improving thin-wall welding structure assembly precision in the actual large-size welding structure assembly process in future.
基金The Natural Science Foundation of Jiangsu Province,China(No.BK20200470)China Postdoctoral Science Foundation(No.2021M691595)Innovation and Entrepreneurship Plan Talent Program of Jiangsu Province(No.AD99002).
文摘The finite element(FE)-based simulation of welding characteristics was carried out to explore the relationship among welding assembly properties for the parallel T-shaped thin-walled parts of an antenna structure.The effects of welding direction,clamping,fixture release time,fixed constraints,and welding sequences on these properties were analyzed,and the mapping relationship among welding characteristics was thoroughly examined.Different machine learning algorithms,including the generalized regression neural network(GRNN),wavelet neural network(WNN),and fuzzy neural network(FNN),are used to predict the multiple welding properties of thin-walled parts to mirror their variation trend and verify the correctness of the mapping relationship.Compared with those from GRNN and WNN,the maximum mean relative errors for the predicted values of deformation,temperature,and residual stress with FNN were less than 4.8%,1.4%,and 4.4%,respectively.These results indicate that FNN generated the best predicted welding characteristics.Analysis under various welding conditions also shows a mapping relationship among welding deformation,temperature,and residual stress over a period of time.This finding further provides a paramount basis for the control of welding assembly errors of an antenna structure in the future.
基金This research was supported by the National Natural Science Foundation of China （51171093）.
文摘Based on full scale model of 1-beam and end-plate welding assembly with medium plate, welding temperature field and residual stress were simulated, infrared thermometers were employed to measure the real-time temperature Jbr verification purposes. Results show that the measured thermal cycle curves match well with the simulation result. Simulation results of welding residual stress indicate that the values of longitudinal and transverse stress on the upper surface of the plate are higher than the normal stress; higher tensile stresses exist at the end of the web weld toes and in the central area of the flange weld toes. The dangerous zones are located at the central areas of weld toes of the flange welds and near weld toes of the web welds.
文摘Two types of automatic systems.for assembly welding. Santana automobile muffler in mass production are suggested in this paper Such systems were aPPlied to manufacture at the beginning of 1995, and were approved to have high productivity and quality but low cost. It is an optimal selection for someone who manufacture automobile muffler or Similar productlons.
基金supported by the National Natural Science Foundation of China(Nos.51905103,52275177).
文摘Multifunctional flexible sensors as wearable electronic systems have attracted considerable attention for mimicking human skin to sense ambient stimuli.However,sensors need to have high resolution,stability and sensitivity to realize fully biomimetic skin.Here,an assembled and welded Ag/W composite nanowire flexible electrode was prepared for body motion monitoring and flexible heaters.This Ag/W composite nanowire flexible electrode has a high transmittance of 90.1%(at 121Ω·sq^(−1) sheet resistance)and a low sheet resistance of 27Ω·sq^(−1)(at 60.1%transmittance).Although the transparency of this electrode is not high,the fluctuation in relative resistance change rate at 10%strain is only 5%after 1000 tensile cycles.It can be employed to monitor human body motions,including bending of fingers,arms,wrists,and throat action.Meanwhile,the Ag/W nanowires composite film heater achieves a steady-state temperature of up to 100℃ at a constant voltage of 3.5 V and an instantaneous heating rate of up to 36.5℃·s^(−1).
基金This project is supported by National 863 Plan (No.2001AA411140)National Natural Science Foundation of China (No.50175071).
文摘There are many welding fixture layout design problems of flexible parts inbody-in-white assembly process, which directly cause body assemble variation. The fixture layoutdesign quality is mainly influenced by the position and quantity of fixture locators and clamps. Ageneral analysis model of flexible assembles deformation caused by fixture is set up based on'N-2-l' locating principle, in which the locator and damper are treated as the same fixture layoutelements. An analysis model for the flexible part deformation in fixturing is set up in order toobtain the optimization object function and constraints accordingly. The final fixture elementlayout could be obtained through global optimal research by using improved genetic algorithm, whicheffectively decreases fixture elements layout influence on flexible assembles deformation.
文摘The level of automation in the manufacture of recreational aluminum boats is very low. Robotized welding is rarely utilized, although it is commonly considered as the most effective way to reduce costs and increase competitiveness. A reason for the under-exploitation of robotics can be found in the construction of aluminum boats;boat models and their detailed structures are almost without exception individual pieces. A new stiffener structure for an aluminum recreational boat hull is developed in this work. Construction of the stiffener as a module allows exploitation of the advantages of modularization. The number of different parts is reduced and the structure simplified improves the applicability of robotic welding and provides benefits accruing from mass production. The same module can be used in several boat models. The modularity also makes it possible to use the same advanced robot welding fixture for a variety of boat models.
文摘A new radial friction welding technology of 30 mm shell's band is introduced.Bands are assembled to shell bodies without notches by using the process.The width of heat-affected zone(HAZ) is small,and the microstructure on steel side is incomplete quenching while that on cooper side is grain refining.The shear-strength of joint exceeds 200 MPa.The result of firing test indicates that radial friction welding can satisfy the assembly requirements of shell bands.
文摘The ultrasonic welding process for wires is being largely used on industry mainly on applications that involve the connectionbetween similar or different metals. The biggest benefit of this technology is the possibility to perform the weld without additionmaterials, like terminals, metal rings or tapes. Manufacturing of wiring harnesses demands a significant amount of joining, such aswelding, crimping or soldering, to fulfill the desired layout of the harnesses and capacity requirements, but conventional connectionprocesses, face difficulties in joining multiple cross sections mainly due to the characteristics of the processes and equipment in use.Ultrasonic metal welding process overcomes these issues due to the solid-state characteristics inherent to the process itself that includethe excellent electrical properties of the joint. Several researches on ultrasonic metal welding are being done to define the fundamentalmechanisms behind this process and it is being seen that they are completely dependent on the cross section to be welded. With thisresearch we are trying to develop methods for process characterization and define acceptable quality parameters in this process. Themain topics addressed in this paper are the characterization the weld formation using copper-to-copper wires using optical microscopyand the analysis of insulation material when submitted to different thermal conditions.
