This paper deals with the structure, components, characteristics and work principle of a newly developed automatic arc welding machine for saddle joint seams on large diameter cylinders. The equations for designing th...This paper deals with the structure, components, characteristics and work principle of a newly developed automatic arc welding machine for saddle joint seams on large diameter cylinders. The equations for designing the geometry and dimensions of the cam controlling the moving locus of the welding torch have been derived. This welding machine has successfully been used in automatic welding saddle joint seams on boiler drums with good results and low cost.展开更多
A systematic experimental research work is done for the stability of sunken large diameter cylinder during construction period. It is the first research that gives the method for assessing the stability of the larger ...A systematic experimental research work is done for the stability of sunken large diameter cylinder during construction period. It is the first research that gives the method for assessing the stability of the larger diameter cylindrical structure, a set of values is derived also for the critical stability indices of the large diameter cylinder sunken to the sandy seabed.展开更多
Physical model tests were counducted to predict local scour and maximum scour depth around the large diameter cylinders located in the (sand) seabed under the action of both wave and current . According to the result ...Physical model tests were counducted to predict local scour and maximum scour depth around the large diameter cylinders located in the (sand) seabed under the action of both wave and current . According to the result of tests, an analysis was made on all the factors influencing the scour. The results shows that for the seabed with relative fine grains in shallow water (0.07<h/L≤0.28),when the relative diameter D/L of the cylinder is within 0.3 0.7,the main effective scour factors around the cylinder in the seabed are diameter D of the cylinder, the wave height H, the wave length L, the velocity V c of the current and the parameters related to the seabed soil texture. The main parameters influecing the maximum scour depth were analyzed, and the test data were syntherized, to obtain the formula predicting the scour depth around the large diameter cylinder under the of both wave and current.展开更多
文摘This paper deals with the structure, components, characteristics and work principle of a newly developed automatic arc welding machine for saddle joint seams on large diameter cylinders. The equations for designing the geometry and dimensions of the cam controlling the moving locus of the welding torch have been derived. This welding machine has successfully been used in automatic welding saddle joint seams on boiler drums with good results and low cost.
文摘A systematic experimental research work is done for the stability of sunken large diameter cylinder during construction period. It is the first research that gives the method for assessing the stability of the larger diameter cylindrical structure, a set of values is derived also for the critical stability indices of the large diameter cylinder sunken to the sandy seabed.
基金Project supported by the National Natural Science Foundation of China (Grant No: 59979003).
文摘Physical model tests were counducted to predict local scour and maximum scour depth around the large diameter cylinders located in the (sand) seabed under the action of both wave and current . According to the result of tests, an analysis was made on all the factors influencing the scour. The results shows that for the seabed with relative fine grains in shallow water (0.07<h/L≤0.28),when the relative diameter D/L of the cylinder is within 0.3 0.7,the main effective scour factors around the cylinder in the seabed are diameter D of the cylinder, the wave height H, the wave length L, the velocity V c of the current and the parameters related to the seabed soil texture. The main parameters influecing the maximum scour depth were analyzed, and the test data were syntherized, to obtain the formula predicting the scour depth around the large diameter cylinder under the of both wave and current.
