A ship's tail shaft has serious flexural vibration due to the cantilevered nature of the propeller's blades.Analysis of the nature frequency of flexural vibration is vital to be able to provide effective shock...A ship's tail shaft has serious flexural vibration due to the cantilevered nature of the propeller's blades.Analysis of the nature frequency of flexural vibration is vital to be able to provide effective shock absorption for a ship's tail shaft.A mathematic model of tail shaft flexural vibrations was built using the transfer matrix method.The nature frequency of flexural vibration for an electrically propelled ship's tail shaft was then analyzed,and an effective method for calculating it was proposed:a genetic algorithm(GA),which calculates the nature frequency of vibration of a system.Sample calculations,with comparisons by the Prohl method under conditions bearing isotropic support,showed this method to be practical.It should have significant impact on engineering design theory.展开更多
In 1866, after the Opium Wars, the Chinese official Zuo Zongtang established the Foochow Navy Yard, which aimed to facilitate the independent construction of modern warships. French advisers, engineers, teachers, and ...In 1866, after the Opium Wars, the Chinese official Zuo Zongtang established the Foochow Navy Yard, which aimed to facilitate the independent construction of modern warships. French advisers, engineers, teachers, and craftsmen were hired, and a series of French schools for naval construction, drawing, and apprenticeship were set up. Previous studies have nearly exhausted the historical material on the Foochow Navy Yard, but few of them give an exact evaluation on its shipbuilding and educational levels. This paper traces the French sources on the shipbuilding technology and educational system at the Foochow Navy Yard and conducts a comparative study. With the guidance and assistance of foreigners, the Foochow Navy Yard gained the ability to assemble ships and imitate engines, while it remained necessary to import design drawings and structural components. The most outstanding students that the navy yard nurtured may have reached the level of école Polytechnique graduates, but the quality of students was hard to maintain. The backwardness of its conceptualization and the lack of financial and political support also contributed to its decline.展开更多
基金the National Natural Science Foundation under Grant No.50675162
文摘A ship's tail shaft has serious flexural vibration due to the cantilevered nature of the propeller's blades.Analysis of the nature frequency of flexural vibration is vital to be able to provide effective shock absorption for a ship's tail shaft.A mathematic model of tail shaft flexural vibrations was built using the transfer matrix method.The nature frequency of flexural vibration for an electrically propelled ship's tail shaft was then analyzed,and an effective method for calculating it was proposed:a genetic algorithm(GA),which calculates the nature frequency of vibration of a system.Sample calculations,with comparisons by the Prohl method under conditions bearing isotropic support,showed this method to be practical.It should have significant impact on engineering design theory.
文摘In 1866, after the Opium Wars, the Chinese official Zuo Zongtang established the Foochow Navy Yard, which aimed to facilitate the independent construction of modern warships. French advisers, engineers, teachers, and craftsmen were hired, and a series of French schools for naval construction, drawing, and apprenticeship were set up. Previous studies have nearly exhausted the historical material on the Foochow Navy Yard, but few of them give an exact evaluation on its shipbuilding and educational levels. This paper traces the French sources on the shipbuilding technology and educational system at the Foochow Navy Yard and conducts a comparative study. With the guidance and assistance of foreigners, the Foochow Navy Yard gained the ability to assemble ships and imitate engines, while it remained necessary to import design drawings and structural components. The most outstanding students that the navy yard nurtured may have reached the level of école Polytechnique graduates, but the quality of students was hard to maintain. The backwardness of its conceptualization and the lack of financial and political support also contributed to its decline.
