Firstly, sample square-circular transition tube along straight central route was modeled on CATIA software. The parameters are as follows： let the tube length is L, and the constant cross section area is S, and S = ...Firstly, sample square-circular transition tube along straight central route was modeled on CATIA software. The parameters are as follows： let the tube length is L, and the constant cross section area is S, and S = πR^2 = a2, in which R stands for the circle radius on one end, and a the square side length on the other end; set up the coordinate system with OX axis on the central route in which the origin O is on centroid of the square end and assume the cross section size at x as the square shaped with all four comers filleted in radius r which is proportional to x, that is, the linear slope of r is R/L, thus, both values r and square side length ax can be attained on the constant cross section area assumption. Secondly, some sample polygonal-circular transition tubes along straight, circular and helical central route were implemented similarly. Thirdly, numerical analysis of stress and displacement of these tubes were carried out on MSC/PATRAN software which are important to the distribution of turbulent flow and the layout of these transitional tube structures.展开更多
In marine application,marine grade steel is generally used for haul and superstructures.However,aluminum has also become a good choice due to its lightweight qualities,while rusting of aluminum is minimal compared to ...In marine application,marine grade steel is generally used for haul and superstructures.However,aluminum has also become a good choice due to its lightweight qualities,while rusting of aluminum is minimal compared to steel.In this paper a study on friction stir welding of aluminum alloys was presented.The present investigation deals with the effects of different friction stir welding tool geometries on mechanical strength and the microstructure properties of aluminum alloy welds.Three distinct tool geometries with different types of shoulder and tool probe profiles were used in the investigation according to the design matrix.The effects of each tool shoulder and probe geometry on the weld was evaluated.It was also observed that the friction stir weld tool geometry has a significant effect on the weldment reinforcement,microhardness,and weld strength.展开更多
Ti6Al4V hip joint was foundered and the filling process of the melt poured in permanent mould during the centrifugal casting process was analyzed and the mathematical model of the filling process was established. Furt...Ti6Al4V hip joint was foundered and the filling process of the melt poured in permanent mould during the centrifugal casting process was analyzed and the mathematical model of the filling process was established. Furthermore, the mathematical model was validated with a wax model experiment. Calculating results show that the centrifugal field has an important influence on the filling process and the melt fills the mould with variational cross sectional area and inclined angle. The cross sectional area is in inverse proportion to the filling speed and its decreasing speed becomes fast with increasing rotating speed. The tangential value of the melt cross sectional free surface inclined angle is in direct proportion to the filling speed and the inclined angle increases with the filling length. Change curves of the cross sectional inclined angle and area were obtained by the wax model experiment when the rotating speeds were 60, 90 and 120 r/min respectively, which shows that the mathematical model is consistent with the experimental results. [展开更多
文摘Firstly, sample square-circular transition tube along straight central route was modeled on CATIA software. The parameters are as follows： let the tube length is L, and the constant cross section area is S, and S = πR^2 = a2, in which R stands for the circle radius on one end, and a the square side length on the other end; set up the coordinate system with OX axis on the central route in which the origin O is on centroid of the square end and assume the cross section size at x as the square shaped with all four comers filleted in radius r which is proportional to x, that is, the linear slope of r is R/L, thus, both values r and square side length ax can be attained on the constant cross section area assumption. Secondly, some sample polygonal-circular transition tubes along straight, circular and helical central route were implemented similarly. Thirdly, numerical analysis of stress and displacement of these tubes were carried out on MSC/PATRAN software which are important to the distribution of turbulent flow and the layout of these transitional tube structures.
文摘In marine application,marine grade steel is generally used for haul and superstructures.However,aluminum has also become a good choice due to its lightweight qualities,while rusting of aluminum is minimal compared to steel.In this paper a study on friction stir welding of aluminum alloys was presented.The present investigation deals with the effects of different friction stir welding tool geometries on mechanical strength and the microstructure properties of aluminum alloy welds.Three distinct tool geometries with different types of shoulder and tool probe profiles were used in the investigation according to the design matrix.The effects of each tool shoulder and probe geometry on the weld was evaluated.It was also observed that the friction stir weld tool geometry has a significant effect on the weldment reinforcement,microhardness,and weld strength.
文摘Ti6Al4V hip joint was foundered and the filling process of the melt poured in permanent mould during the centrifugal casting process was analyzed and the mathematical model of the filling process was established. Furthermore, the mathematical model was validated with a wax model experiment. Calculating results show that the centrifugal field has an important influence on the filling process and the melt fills the mould with variational cross sectional area and inclined angle. The cross sectional area is in inverse proportion to the filling speed and its decreasing speed becomes fast with increasing rotating speed. The tangential value of the melt cross sectional free surface inclined angle is in direct proportion to the filling speed and the inclined angle increases with the filling length. Change curves of the cross sectional inclined angle and area were obtained by the wax model experiment when the rotating speeds were 60, 90 and 120 r/min respectively, which shows that the mathematical model is consistent with the experimental results. [
