The current collector fracture failure of lithium-ion batteries(LIBs)occurs during its winding production process frequently,and the consequent damages are usually large,but little research has been conducted on this ...The current collector fracture failure of lithium-ion batteries(LIBs)occurs during its winding production process frequently,and the consequent damages are usually large,but little research has been conducted on this phenomenon.This work stems from the difficulty and obstacles in the winding process of actual production of LIBs.The fracture failure of the current collectors is easily caused by the evolution and mutation of the mechanical behavior during the winding process,resulting in safety hazards and poor efficiency.The purpose of this work is to reveal the evolution and distribution mechanism of circumferential strain of the current collectors on the fracture failure under the constraint of winding process.Experimental tests,finite element calculations and theoretical model are used to study the evolution and distribution of circumferential strain.The dynamic evolution process of circumferential strain is tested accurately,and the mechanism of fracture failure of current collectors is revealed.The criterion for current collector strength is proposed based on the results of strain analysis and SEM observation.展开更多
In order to achieve integration of electrmotion and manual operation for manual forklift, this paper designs an improved manual forklift. We select the appropriate motor according to parameters of original manual fork...In order to achieve integration of electrmotion and manual operation for manual forklift, this paper designs an improved manual forklift. We select the appropriate motor according to parameters of original manual forklift, which was analyzed by SolidWorks. We make the detailed design of the speed reducer according to the selected motor＇s rated speed and other parameters, and design the reduction speed ratio, reduction speed form, size of gear drive, meshing parameters, force analysis of gear and strength check. In this paper, we electrify the traditional manual forklift eventually.展开更多
Gas drilling,as an important part of underbalanced drilling,can increase drilling speed.But in the process of conventional gas drilling,it tends to cause cutting settlement,borehole collapse,sticking and other safety ...Gas drilling,as an important part of underbalanced drilling,can increase drilling speed.But in the process of conventional gas drilling,it tends to cause cutting settlement,borehole collapse,sticking and other safety hazards because gas circulation has to be interrupted.Therefore,this paper presents a continuous circulation sub which can be installed and removed easily.With this sub,gas circulation will not be interrupted when drilling tools are connected and removed.This sub is composed of body,main valve,bypass valve and side entry sub.The structure design of its key components(i.e.main and bypass valves)were fulfilled.Based on statics analysis on the sub body,its force situations under extension,torsion and internal pressure were simulated by using the ANSYS finite element analysis software.It is shown that its stress distribution trend is consistent with its elasticeplastic mechanics analysis results.Stress concentrates around the two round holes of the sub body,and the maximum deformation amount is still at the stage of elastic deformation.The analysis results are in line with the elasticeplastic mechanics analysis results,and the requirement of body strength is satisfied.This paper provides a new program to guarantee the drilling safety of extended-reach wells,underbalanced wells and narrow-density window wells.展开更多
Improper drilling parameters may cause severe vibration of drill string which leads to reduce the rate of penetration and drilling tool premature failure accidents in the drilling process of ultra-deep well.The study ...Improper drilling parameters may cause severe vibration of drill string which leads to reduce the rate of penetration and drilling tool premature failure accidents in the drilling process of ultra-deep well.The study on dynamic characteristics of drill string plays an important role in increasing the safety of drilling tool and optimizing the drilling parameters.Considering the influences of real borehole trajectory,interaction between bit and formation,contact between drill string and borehole wall,stiction of drilling fluid and other factors,a comprehensive drill string dynamic model was established to simulate the changes of wellhead hook load,torque,equivalent stress of drill string and BHA(bottomhole assembly)section acceleration and motion trajectory with time at different WOBs(weights on bit)and rotary speeds.The safety factor and overpull margin of wellhead drill string were calculated and the strength of drilling tool in ultra-deep well was checked using the fourth strength theory.The analysis results show that,in the drilling process of ultra-deep well,the transverse motion amplitude of the drill string near the wellhead is relatively small and vibration of drill string mainly occurs in the lower well section.As the rotary speed increases,the number of collision between lower drilling tool and borehole wall increases,wellhead transverse stress increases,change in torque is not large and change in wellhead equivalent stress is relatively small.As the WOB increases,wellhead torque will increase,axial load and equivalent stress will decrease and vibration acceleration of BHA will increase sharply.Wellhead overpull margin and safety factor will decrease with the increase of rotary speed and increase with the increase of WOB.Wellhead safety factor of S135 drilling tool in an F190.5 mm ultra-deep well on the south margins of Junggar basin changes around 1.8.The drilling tool is safe and has relatively sufficient ability to deal with the downhole accidents if a large size high steel grade drill string(F139.7 mm S135)is used.However,in view of BHA safety,neither rotary speed shall be too high nor WOB shall be too large.展开更多
基金National Natural Science Foundation of China(12002183)Postdoctoral Science Foundation(2019TQ0171,2020M670304)Beijing Natural Science Foundation(Grant Nos.16L00001 and 2182065)are Rratefullv acknowledged.
文摘The current collector fracture failure of lithium-ion batteries(LIBs)occurs during its winding production process frequently,and the consequent damages are usually large,but little research has been conducted on this phenomenon.This work stems from the difficulty and obstacles in the winding process of actual production of LIBs.The fracture failure of the current collectors is easily caused by the evolution and mutation of the mechanical behavior during the winding process,resulting in safety hazards and poor efficiency.The purpose of this work is to reveal the evolution and distribution mechanism of circumferential strain of the current collectors on the fracture failure under the constraint of winding process.Experimental tests,finite element calculations and theoretical model are used to study the evolution and distribution of circumferential strain.The dynamic evolution process of circumferential strain is tested accurately,and the mechanism of fracture failure of current collectors is revealed.The criterion for current collector strength is proposed based on the results of strain analysis and SEM observation.
基金Supported by Science and Technology Researcher Project of Anhui Province(15czz02030)International Scientific and Technological Cooperation Projects of China(No.2013DFB70350)
文摘In order to achieve integration of electrmotion and manual operation for manual forklift, this paper designs an improved manual forklift. We select the appropriate motor according to parameters of original manual forklift, which was analyzed by SolidWorks. We make the detailed design of the speed reducer according to the selected motor＇s rated speed and other parameters, and design the reduction speed ratio, reduction speed form, size of gear drive, meshing parameters, force analysis of gear and strength check. In this paper, we electrify the traditional manual forklift eventually.
文摘Gas drilling,as an important part of underbalanced drilling,can increase drilling speed.But in the process of conventional gas drilling,it tends to cause cutting settlement,borehole collapse,sticking and other safety hazards because gas circulation has to be interrupted.Therefore,this paper presents a continuous circulation sub which can be installed and removed easily.With this sub,gas circulation will not be interrupted when drilling tools are connected and removed.This sub is composed of body,main valve,bypass valve and side entry sub.The structure design of its key components(i.e.main and bypass valves)were fulfilled.Based on statics analysis on the sub body,its force situations under extension,torsion and internal pressure were simulated by using the ANSYS finite element analysis software.It is shown that its stress distribution trend is consistent with its elasticeplastic mechanics analysis results.Stress concentrates around the two round holes of the sub body,and the maximum deformation amount is still at the stage of elastic deformation.The analysis results are in line with the elasticeplastic mechanics analysis results,and the requirement of body strength is satisfied.This paper provides a new program to guarantee the drilling safety of extended-reach wells,underbalanced wells and narrow-density window wells.
基金This work is financially supported by National Natural Science Foundation of China(Grant No.52104006 and Grant No.51674215).
文摘Improper drilling parameters may cause severe vibration of drill string which leads to reduce the rate of penetration and drilling tool premature failure accidents in the drilling process of ultra-deep well.The study on dynamic characteristics of drill string plays an important role in increasing the safety of drilling tool and optimizing the drilling parameters.Considering the influences of real borehole trajectory,interaction between bit and formation,contact between drill string and borehole wall,stiction of drilling fluid and other factors,a comprehensive drill string dynamic model was established to simulate the changes of wellhead hook load,torque,equivalent stress of drill string and BHA(bottomhole assembly)section acceleration and motion trajectory with time at different WOBs(weights on bit)and rotary speeds.The safety factor and overpull margin of wellhead drill string were calculated and the strength of drilling tool in ultra-deep well was checked using the fourth strength theory.The analysis results show that,in the drilling process of ultra-deep well,the transverse motion amplitude of the drill string near the wellhead is relatively small and vibration of drill string mainly occurs in the lower well section.As the rotary speed increases,the number of collision between lower drilling tool and borehole wall increases,wellhead transverse stress increases,change in torque is not large and change in wellhead equivalent stress is relatively small.As the WOB increases,wellhead torque will increase,axial load and equivalent stress will decrease and vibration acceleration of BHA will increase sharply.Wellhead overpull margin and safety factor will decrease with the increase of rotary speed and increase with the increase of WOB.Wellhead safety factor of S135 drilling tool in an F190.5 mm ultra-deep well on the south margins of Junggar basin changes around 1.8.The drilling tool is safe and has relatively sufficient ability to deal with the downhole accidents if a large size high steel grade drill string(F139.7 mm S135)is used.However,in view of BHA safety,neither rotary speed shall be too high nor WOB shall be too large.
