基于ACIS的数控加工仿真系统的研究

利用基于组件技术的ACIS几何造型平台，建立了基于ACIS的数控加工仿真系统的体系结构，分析了数控加工仿真中模型的几何与拓扑信息，确定了几何模型的数据结构，建立了数控加工仿真的几何模型，并讨论了如何通过API接口函数来实现对模型操作的方法。     

不确定性系统的控制策略及其与实现相关的软件技术

在实际工业现场，控制系统的复杂性不仅表现在结构上．更多的是表现在信息关系的不确定性和复杂程度上，对这类被控对象进行有效控制的关键是选取适合的控制策略．基于对控制策略的分析对比。建议采用仿人智能控制策略，利用广义控制论模型实现对不确定性复杂对象的控制．为强化管控一体化功能。文章对一类复杂系统工程实现的软件系统构架也作了讨论，并给出了一个应用实例．     

基于MultiGen和Vega的场景仿真系统技术

复杂场景的漫游仿真在城市规划、旅游观光、虚拟战场等领域有着极为广泛的应用前景．将仿真技术引入“数字校园”的研究中．开发可视化的用户操作界面。为校园的规划和设计提供了一种全新的手段．本分析了基于Multigen和Vega的软件平台上场景仿真系统的整体结构．论述了在开发仿真系统过程中的一些关键技术．包括数据处理流程、三维建模、Vega软件的二次开发．结论表明．利用Multigen和Vega技术开发的场景仿真系统的方法是切实可行的．若结合GIS技术将有着良好的市场应用前景．     

基于MATLAB的机器人运动仿真研究

按照一定的要求对一种柱面坐标机器人进行了参数设计，讨论了该机器人的运动学问题，然后在MATLAB环境下，用Robotics Toolbox对该机器人的正运动学、逆运动学、轨迹规划进行了仿真．通过仿真．观察到了机器人各个关节的运动．并得到了所需的数据．说明了所设计的参数是正确的．从而能够达到预定的目标，     

自由圆柱壳受冲击载荷作用的动力响应仿真分析

以自由圆柱壳为对象,利用大型有限元程序LS-DYNA对自由柱壳在其中心部位经受刚性、平头弹体侧向冲击时的动力响应问题进行了仿真分析,得到自由柱壳在侧向冲击时的变形历程和最终的变形模态以及能量分配等方面的相关结果,分析了自由圆柱壳对冲击载荷的响应特点,为进一步的理论分析提供参考。     

复合材料风机叶轮内流场数值模拟

应用粘性流体力学的基本原理,采用专业流体力学软件对复合材料风机叶轮内气流流动进行数值模拟,发现叶轮内气流流动状况不理想,据此对叶轮的叶片进行改进设计,得到了改进叶片设计后叶轮内的流场,改进了复合材料风机叶轮的结构,改善了叶轮内部气流的流动状况,提高了叶轮的气动性能,为研制出高性能的新型复合材料风机叶轮奠定了基础。     

地板送风静压层内气流的数值模拟与送风特性实验

采用计算流体力学(CFD)技术,对地板送风静压层的空气流动进行了数值模拟,并进行了典型的实验来验证计算结果.通过对计算结果与实验结果的比较,说明对于地板送风静压层内空气流动的CFD模拟,采用0 1 m的网格划分间距、标准k ε湍流模型是合理的.实验和计算结果一致表明,对于高度为170 mm的地板送风静压层,地板送风口的速度和送风量分布受到入口射流的影响,处于不同位置的地板送风口,其速度分布不同,有的均匀,有的速度值相差10倍.由数值模拟的地板送风静压层内空气流动特征,可展示和分析地板送风静压层的以上送风特性.     

Atomic-scale computer simulation for early precipitation process of Ni75AlxV25-x alloy with intermediate Al composition

The microscopic phase-field approach is applied to model the early precipitation process of Ni75AlxV25-x alloy. Without any prior assumptions, this model can be used to simulate the temporal evolution of arbitrary morphologies and microstructures on atomic scale. By simulating the atomic pictures, and calculating the order parameters and volume fraction of the θ (Ni3V) and γ'(Ni3Al) ordered phases, we study Ni75AlxV25-x alloys with Al composition of 0.05, 0. 053 and 0. 055 (atom fraction). Our calculated results show that,for these alloys, θ and γ' phases precipitate at the same time; with the increase of Al content, the amount of γ' phase increases and that of θ phase decreases; the precipitation characteristic of γ' phase transforms from Non-Classical Nucleation and Growth (NCNG) to Congruent Ordering Spinodal Decomposition (CO SD) gradually; otherwise, the precipitation characteristic of θ phase transforms from Congruent Ordering Spinodal Decomposition (CO SD) to Non-Classical Nucleation and Growth (NCNG) mechanism gradually. Both θ and γ' phases have undergone the transition process of mixture precipitation mechanism characterized by both NCNG and CO SD mechanisms. No incontinuous transition of precipitation mechanism has been found.     

Computational fluid dynamics for dense gas-solid fluidized beds

Many computational fluid dynamics (CFD) models for describing the hydrodynamics of dense gas-solid flows in fluidized beds have been put forward in the past few decades. These models treat the solid phase as continuum or discrete particles, which leads to Eulerian-Eulerian or Eulerian-Lagrangian formulations, respectively. Different governing equations and closure relations essentially result from an insufficient understanding of the complex gas?particle and particle?particle interactions for gas?solid flows. The current status of these models is discussed briefly in this paper. All the approaches in the literature modify only the solid phase momentum balance equation introducing various forms of the solid phase stress tensor and the solid phase pressure drop in the Eulerian-Eulerian models. Taking them into consideration, a new model for predicting the fluid behavior of dense gas?solid flows in fluidized beds has been developed, which contains new terms in both the particle and gas phase momentum balance equations and requires only the use of an experimental drag force correlation. Several results are shown to verify the model’s reliability, which include the homogeneous fluidization of Geldart type A particles, the bubbling and jetting fluidization of Geldart type B particles in rectangular beds, and fluid dynamics in a complicated geometry for a bubbling?bed of a fast internally circulating fluidized?bed biomass gasifier.     

频率色散移动信道的仿真模型分析

通过分析频率色散移动信道的衰落特性，分别对该信道在快衰落特性，慢衰落特性以及同时考虑快衰落和慢衰落这三种情况下建立了数学模型和计算机仿真模型，并对计算机仿真结果进行了分析，得出相应结论。