带内齿和内花键的汽车齿轮热处理变形的控制方法

分析了带内齿和内花键的汽车齿轮的热处理变形规律,对这几类汽车齿轮热处理变形的控制方法进行了全面和有创新性的研究,从齿轮原材料淬透性、齿坯预备热处理工艺、齿轮最终热处理变形的控制方法、热处理变形校正措施等多方面内容进行了有实际运用价值的阐述,解决了这几类齿轮的热处理变形难以控制的问题。     

基于VBA的矩形花键拉刀参数化设计

应用AutoCAD集成开发工具VBA,建立了矩形花键拉刀设计人机交互界面;采用参数化绘图技术,实现了矩形花键拉刀图形的自动布局与自动绘制的功能;结果表明其完全满足工程实践要求.     

Calculation of hydrodynamics for semi-submersibles based on NURBS

Accurate hydrodynamic calculations for semi-submersibles are critical to support modern rapid exploration and extraction of ocean resources. In order to speed hydrodynamic calculations, lines modeling structures were separated into structural parts and then fitted to Non-uniform Rational B-spline （NURBS）. In this way, the bow and stern section lines were generated. Modeling of the intersections of the parts was then done with the universal modeling tool MSC.Patran. Mesh was gererated on the model in order to obtain points of intersection on the joints, and then these points were fitted to NURBS. Next, the patch representation method was adopted to generate the meshes of wetted surfaces and interior free surfaces. Velocity potentials on the surfaces were calculated separately, on basis of which the irregular frequency effect was dealt with in the calculation of hydrodynamic coefficients. Finally, the motion response of the semi-submersible was calculated, and in order to improve calculations of vertical motion, a damping term was affixed in the vertical direction. The results show that the above methods can generate fine mesh accurately representing the wetted surface of a semi-submersible and thus improve the accuracy of hydrodynamic calculations.