椭圆形截面织构的最优参数设计模型

为建立流体润滑状态下表面织构的最优参数设计模型,采用求解表面织构润滑计算模型的方法研究织构参数和工况参数对摩擦因数的影响规律。研究结果表明:最优织构直径越大,其对应的最优织构深度也越大;深径比参数不能作为织构尺寸参数对摩擦因数影响的唯一表征,即织构直径和深度2个参数应分别进行研究,但当深径比在0.005～0.01之间时,不论织构直径和深度如何,其对应的摩擦因数均较小;最优织构面积比与织构尺寸参数及工况参数无关;载荷越大,速度越小,对应的最优织构深度越小,而最优织构直径越大。在仿真结果的基础上,建立椭圆形截面织构的最优参数设计模型,并对模型进行试验验证和应用分析。

一个基于约束图的参数化设计模型

基于图论的约束求解方法是目前参数化设计的主要方法,此方法已经应用于许多商品化软件中。该文提出了一个基于几何约束图的参数化设计模型,并给出了参数化模型的数据结构和约束求解算法。此算法可以有效地检查系统的过约束和欠约束情况。

建筑设计参数分析模型对工程造价估算的影响分析

对建筑设计参数分析模型与工程造价估算的关系进行研究,研究发现,引用的参数越多,估算准确率越高。进而分析了构建参数分析模型对工程造价估算的影响,该方法能够帮助企业领导者从全局把控形式,寻求最佳投资方式,有效避免资金浪费。

基于Matlab/Simulink的离子推力器输入参数设计模型研究

离子推力器的输入参数设计直接决定其工作性能以及寿命,为了有效降低在前期设计阶段,由于输入参数设计缺陷导致的输出性能和预估寿命不一致性,以及后期优化改进所带来的风险及高昂成本,根据离子推力器工作过程的宏观描述以及寿命理论预估方法,基于Matlab/Simulink建立起离子推力器输入参数设计模型,实现了根据推力、比冲、效率等设计指标完成输入参数计算以及寿命预估的目的。结果显示:以30cm离子推力器为例,根据参数设计模型得到5kW额定工况下的关键输入参数与目前实际输入参数的比对误差均在5%以内,而模型得到的关键指标参数与冷启动试验测试值的比对误差同样在5%以内,3600h后的加速栅孔径刻蚀计算结果与试验结果比对误差在10%以内,证明了离子推力器输入参数设计模型的合理性,输入参数设计模型可用于后续同类型离子推力器的早期输入参数确定以及设计指标匹配性评价。

机械产品设计中基于多模型集成的二次开发技术研究

针对相似程度高及可系列化的产品结构,提出以多模型切换设计和功能可扩展为要求的功能一体化多模型集成参数化设计方法。将二次开发技术与企业产品设计相结合,研究了模型信息集成检入切换、参数驱动和元件指定操作的二次开发技术,解决了Creo软件在产品设计过程中部分功能步骤繁琐、效率不高的问题,并研究了一种参数检索的方法,以实现系统的参数自动更新。以某公司压路机十字轴焊接件设计为例,结合MFC可视化技术搭建人机交互界面,基于C语言对Creo软件进行了多模型集成参数化设计系统开发,验证了此设计方法的高效性和实用性。

Pro／E齿轮参数化设计

参数化设计模型是以约束来表达产品模型的形状特征，以一组参数来控制设计结果，从而能通过变换一组参数值方便地创建一系列形状相似的零件。

潜流人工湿地污水处理技术的效能与设计

潜流人工湿地污水处理技术的研究和开发尚属较新领域 ,本文介绍了该技术处理污水的效能和设计参数模型 。

基于约束映射关系的二维几何约束模型

在系统实现的基础上 ,提出一种依据设计过程确定约束依赖关系的参数化设计模型 ,建立约束和图元之间的映射模式 ,优化确定节点之间的更新从动性 ,从而降低约束求解的复杂度 .用户添加的约束和系统自动识别的约束能动态添加到有向约束图中 ,并支持任意图形块的选择重复 .实践证明 ,该模型算法简单 ,交互性好 ,能很好理解用户的设计意图 .

基于UG的汽轮机套装油管路设计系统

为开发1套高效的汽轮机套装油管路设计系统,分析汽轮机套装油管路的结构特点及设计方法,提出基于控制链的管路模块化设计和关联性设计等方法.基于UG的套装油管路设计系统,运用模块编码和模板模型参数化等技术开发,实现套装油管路的快速设计.应用实例表明系统可以极大地提高产品设计效率,缩短产品开发周期.

面向任务级弹道导弹的通用弹道设计仿真研究

任务级作战仿真能够在保证需求精度前提下,参数化运动模型,实现大批量实体、海量交互的通用性,满足任务级作战仿真需求。首先根据任务级作战仿真特点,建立了模型子系统交互映射关系,按照弹体结构不同功能提出了飞行级概念。其次通过对模型和数据的分离及对弹道导弹参数的模块化处理,以经典运动微分方程组为模型核心,根据飞行级概念设计了一种弹道导弹通用弹道模型。最后以"飞毛腿SCUD-C"导弹为例仿真,得到了飞行高度、速度及弹道倾角对比曲线图。结果表明,在保证战技指标的前提下,上述方法突破了传统弹道仿真模型面向单一型号导弹的局限,实现了一种模型仿真多种弹道导弹型号的功能。

大型精密测量雷达结构精度实现途径

随着高频段、大功率和大口径雷达的发展,雷达结构精度对雷达测角精度、指向精度等方面的影响日趋明显,如何实现大型高频段雷达结构精度是工程实施过程中必须要解决的问题。文中通过在不同阶段设计和构建相应的参数化模型如:结构精度指标分配模型、尺寸链闭环控制设计模型、轴系精度仿真模型、试验模型及标定模型等;利用参数化模型控制关键参数,如阵面平面度、轴端转角、轴端等高、轴系精度等,从而系统可有效地控制结构精度。

敏捷化开发环境下产品装配建模研究

为了实现以自顶向下为主、自底向上为辅的双向产品设计方法,本文提出了一种面向产品族的混合装配模型。该模型由装配骨架模型、层次模型、约束关系模型、零件属性模型及参数化设计模型组成。通过引入高层次的装配骨架模型反映设计者的设计意图并自动向下游传播装配约束,实现自顶向下面向过程的设计方法;通过引入低层次的约束关系模型记录零件之间的各种约束关系,检验、改进和完成最终装配模型的重建,实现自底向上的面向结果的设计方法;通过引入参数化设计模型完成装配体的变形设计,实现以往知识的重用。最后用实例说明该混合装配建模方法的有效性。

Sliding mode robust controller for automatic rectification of shield machine

According to the actual engineering problem that the precise load model of shield machine is difficult to achieve,a design method of sliding mode robust controller oriented to the automatic rectification of shield machine was proposed. Firstly,the nominal load model of shield machine and the ranges of model parameters were obtained by the soil mechanics parameters of certain geological conditions and the messages of the self-learning of shield machine by tunneling for previous segments. Based on this rectification mechanism model with known ranges of parameters,a sliding mode robust controller was proposed. Finally,the simulation analysis was developed to verify the effectiveness of the proposed controller. The simulation results show that the sliding mode robust controller can be implemented in the attitude rectification process of the shield machine and it has stronger robustness to overcome the soil disturbance.

Combined method for parallel manipulator configuration design

Configuration design is an essential, creative and decision-making step m parallel manipulator design process, in which modeling and assembly are iterative and trivial. Combined approach with automatic parametric modeling and automatic assembly is proposed for parallel manipulator configuration design. The design process and key techniques, such as configuration design, configuration verification, poses calculation of all parts in parallel manipulator, virtual assembly and etc., are discussed and demonstrated by an example. A software package is developed for parallel manipulator configuration design based on the proposed method with Visual C＋＋ and UG/OPEN on Unigraphics.

Variable Relation Parametric Model on Graphics Modelon for Collaboration Design

A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method for different graphic modelon based on variable constraint. At the same time, with the aim of engineering application in the collaboration design, the autonmous constraint in modelon and relative constraint between two modelons are given. Finally, with the tool of variable and relation dbase, the solving method of variable relating and variable-driven among different graphic modelon in a part, and double-acting variable relating parametric method among different parts for collaboration are given.

Optimal control of cobalt crust seabedmining parameters based on simulated annealing genetic algorithm

Under the condition of the designated collection ratio and the interfused ratio of mullock, to ensure the least energy consumption, the parameters of collecting head （the feed speed, the axes height of collecting head, and the rotate speed） are chosen as the optimized parameters. According to the force on the cutting pick, the collecting size of the cobalt crust and bedrock and the optimized energy consumption of the collecting head, the optimized design model of collecting head is built. Taking two hundred groups seabed microtopography for grand in the range of depth displacement from 4.5 to 5.5 era, then making use of the improved simulated annealing genetic algorithm （SAGA）, the corresponding optimized result can be obtained. At the same time, in order to speed up the controlling of collecting head, the optimization results are analyzed using the regression analysis method, and the conclusion of the second parameter of the seabed microtopography is drawn.

Influence of preload discreteness on air-operated separation process of low-shock separation device

To investigate the influence of design parameters on the performance of separation device,the structure and air-operated test of a low-shock separation device are introduced and analyzed in this paper.According to the law of energy conservation and aerodynamics,a mathematical model is built.Because the preload used to ensure the connection reliability has the discreteness,which will influence the separation process,the influence of preload discreteness on the air-operated separation process is simulated and tested.Simulation results are consistent with the experimental results.It is shown that the change of preload has an obvious influence on the separation process.The study is useful for the design and optimization of separation device.

Parametric design of an electrorheological shock absorber with the mixed-mode

A mathematical model based on an electrorheological (ER) shock absorber with the mixed-mode is presented. Its application to the parametric design of an electrorheological fluid shock absorber with the simulation calculation performed by program MATLAB demonstrates that the model can predict the behavior of ER shock absorbers satisfactorily, shorten the design period of an electrorheological shock absorber, and reduce the cost in the prototype manufacturing. The strength analysis based on a three-dimensional finite element model for the electrorheological shock absorber confirm that the structure design of the ER shock absorber is reasonable, and the stress distribution is uniform.

Theoretical generalization of Markov chain random field from potential function perspective

The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial Markov chain(SMC) that can move in the whole space. Generally, the theoretical backbone of MCRF is conditional independence assumption, which is a way around the problem of knowing joint probabilities of multi-points. This so-called Naive Bayes assumption should not be taken lightly and should be checked whenever possible because it is mathematically difficult to prove. Rather than trap in this independence proving, an appropriate potential function in MRF theory is chosen instead. The MCRF formulas are well deduced and the joint probability of MRF is presented by localization approach, so that the complicated parameter estimation algorithm and iteration process can be avoided. The MCRF model is then applied to the lithofacies identification of a region and compared with triplex Markov chain(TMC) simulation. Analyses show that the MCRF model will not cause underestimation problem and can better reflect the geological sedimentation process.

Structural Optimization of Concrete Slab Frame Bridges Considering Investment Cost

The present study investigates computer-antomated design and structural optimization of concrete slab frame bridges considering investment cost based on a complete 3D model. Thus, a computer code with several modules has been developed to produce parametric models of slab frame bridges. Design loads and load combinations are based on the Eurocode design standard and the Swedish design standard for bridges. The necessary reinforcement diagrams to satisfy the ultimate and serviceability limit states, including fatigue checks for the whole bridge, are calculated according to the aforementioned standards. Optimization techniques based on the genetic algorithm and the pattern search method are applied. A case study is presented to highlight the efficiency of the applied optimization algorithms. This methodology has been applied in the design process for the time-effective, material-efficient, and optimal design of concrete slab frame bridges.