It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of pre...It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.展开更多
This paper focuses on advanced analysis techniques and design considerations of DC interference generated by HVDC electrodes during normal bipolar and temporary monopolar operations on neighboring metallic utilities, ...This paper focuses on advanced analysis techniques and design considerations of DC interference generated by HVDC electrodes during normal bipolar and temporary monopolar operations on neighboring metallic utilities, with a special emphasis on buried gas and oil pipelines. This study examines the level of pipeline corrosion, the safety status in the vicinity of exposed appurtenances and the impact of DC interference on the integrity of insulating flanges and impressed current cathodic protection (ICCP) systems. Computation results obtained for different soil models show that different soils can lead to completely different DC interference effects. The results and conclusions presented here can be used as a reference to analyze the severity of DC interference on pipelines due to proximate HVDC electrodes.展开更多
Jacking force is one of the important safety indicators during pipe jacking construction.Existing models for calculating jacking force are widely used in the calculation of jacking force for pipe with regular cross-se...Jacking force is one of the important safety indicators during pipe jacking construction.Existing models for calculating jacking force are widely used in the calculation of jacking force for pipe with regular cross-sections.In this paper,considering pipe-soil interaction,the cross-sectional characteristics and the distribution characteristics between pipe and soil,the calculation equations for the jacking force of circular steel pipe with flange plate were proposed based on the pressure arch theory.The proposed equations were applied to calculate the jacking force for the Olympic Sports Center Subway Station of Line 9 in Shenyang,China,and the results were compared with the field monitoring data to predict the accurate jacking force.Based on the proposed equations,the influences of the flange plate position and steel pipe diameter on earth pressure around the pipe were analyzed.The functional relationship between the earth pressure and the position of flange plate or the pipe diameter was obtained,which provides design basis and theoretical guidance for engineering practice.展开更多
基金Project(51305334)supported by the National Natural Science Foundation of ChinaProject(51335009)supported by the National Natural Science Foundation of China for Key Program+1 种基金Project(CXY1442(4))supported by the Science and Technology Planning Project of Xi’an,ChinaProject supported by Shaanxi Province Postdoctoral Science Research Program of China
文摘It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.
文摘This paper focuses on advanced analysis techniques and design considerations of DC interference generated by HVDC electrodes during normal bipolar and temporary monopolar operations on neighboring metallic utilities, with a special emphasis on buried gas and oil pipelines. This study examines the level of pipeline corrosion, the safety status in the vicinity of exposed appurtenances and the impact of DC interference on the integrity of insulating flanges and impressed current cathodic protection (ICCP) systems. Computation results obtained for different soil models show that different soils can lead to completely different DC interference effects. The results and conclusions presented here can be used as a reference to analyze the severity of DC interference on pipelines due to proximate HVDC electrodes.
基金supported by the National Natural Science Foundation of China(No.51878127).
文摘Jacking force is one of the important safety indicators during pipe jacking construction.Existing models for calculating jacking force are widely used in the calculation of jacking force for pipe with regular cross-sections.In this paper,considering pipe-soil interaction,the cross-sectional characteristics and the distribution characteristics between pipe and soil,the calculation equations for the jacking force of circular steel pipe with flange plate were proposed based on the pressure arch theory.The proposed equations were applied to calculate the jacking force for the Olympic Sports Center Subway Station of Line 9 in Shenyang,China,and the results were compared with the field monitoring data to predict the accurate jacking force.Based on the proposed equations,the influences of the flange plate position and steel pipe diameter on earth pressure around the pipe were analyzed.The functional relationship between the earth pressure and the position of flange plate or the pipe diameter was obtained,which provides design basis and theoretical guidance for engineering practice.
