Numerical Model of Storm Surge and Inundation in Bohai Bay

A two-dimensional numerical model of extratropical storm surge and inundation in Bohai Bay was built based on the unsteady flow Navier-Stokes equations. The model included two sections, one was for the simulation of storm surge tidal level and the other for the simulation of storm surge inundation in the coastal area. While simulating the storm surge tidal level, the alternating direction implicit (ADI) method was applied to dispersing and solving 2D storm surge equations. In the simulation of storm surge inundation, the 2D unsteady flow equations were dispersed and solved using the structureless grids of finite volume method (FVM). A coupling calculation mode of the process of inundation and storm surge tidal level variation was proposed, therefore the storm surge inundation process and area could be calculated while simulating and forecasting the process of storm surge tidal setup. Furthermore, an extratropical storm surge and inundation in Bohai Bay were simulated using this numerical model. Simulation results are in good agreement with the measured data, which shows that this numerical model provides a new method of simulating and forecasting storm surge and inundation in Bohai Bay.     

球墨铸铁等温淬火前后切削加工性能研究

球墨铸铁等温淬火后力学性能大大增强,但切削加工性随之变差。分析热处理后材料微观组织的变化,并采用晶体压电传感测力仪、电荷放大器及计算机组成的切削力数据采集系统测量陶瓷刀具干切削球墨铸铁（DI）及等温淬火处理后的球墨铸铁（ADI）时的切削力。比较不同切削深度、进给速度及切削速度下,DI和ADI两者之间切削力大小关系,观察两者切屑形态的异同,研究球墨铸铁等温淬火前后切削加工性能的变化。结果表明,等温淬火后随着金相组织的转变,材料力学性能大幅增强,切削力大幅增加,切屑短小崩碎．易飞溅,切削加工性能明显变差。     

二维抛物型方程非齐次边值问题的高精度差分格式

针对二维非齐次抛物型方程提出了高精度紧致差分格式，本文将把在[2]中二维问题的差分格式在空间方向上提高到四阶，对其进行了收敛性分析，证明其收敛阶为o（△t^2＋hx^4＋hy^4），并采用ADI算法将二维问题降为一阶求解。     

复合淬火高性能ADI曲轴的研制

通过球铁曲轴的等温淬火和表面超音频淬火复合处理的工艺研究,把等温淬火和超音频淬火两种热处理技术有机地结合在一起,应用于球铁曲轴上,获得了曲轴心部为上贝氏体、残余奥氏体和微量的下贝氏体,保证了心部的高强韧性;表面淬硬层为高密度位错马氏体的综合组织,提高了表层的高耐磨性。其抗拉强度达1 200MPa以上、延长率达到4%~6%、表面硬度达50~58HRC。因此具有优良的力学性能,完全可以取代钢件曲轴应用于中、高端内燃机曲轴。     

代数Riccati方程数值解的一种牛顿迭代法

代数Riccati方程在优化控制理论中具有十分重要的作用.结合了二次方程的牛顿迭代法与Lya-punov方程的自由参数轮转方向迭代法,提出了一种求代数Riccati方程数值解的一种新方法,并给出了算法的收敛性证明.最后,给出了具体的数值算例.     

低合金奥贝球铁的试验研究

采用合理的工艺措施 ,可大大降低铜 (Cu)、镍 (Ni)合金加入量 ,适当放宽锰 (Mn)含量的限制 ,得到性能优异、稳定的奥贝球铁材料     

二维热传导方程的紧ADI法

对二维热传导方程进行紧交替方向有限差分,该方法在空间方向上具有四阶精度,在时间方向上具有二阶精度。证明了当rx,ry≥1／6时该有限差分解收敛于连续解。数值例子验证了该有限差分法具有高阶精度。