Use of a computer molecular simulation to describe lubricating layer structure

The potential of methods of computer molecule dynamics for determining the characteristics of lubricating layers are considered for hydrodynamic and boundary lubrication regimes. Examples of finding parameters of adsorption, supermolecular self-organization, and rheology in lubricating layers are given for model lubricants.     

VBA及MATLAB环境下焊接机器人计算机图形仿真系统的开发

论述AutoCAD2004环境下，以VBA为二次开发工具，实行VBA和数学软件MATLAB的混合编程，把MATLAB作为后拿矩阵计算引擎，成功地实现了焊接机器人计算机三维动态图形仿真。该系统对机器人的研制、设计和试验有实际应用价值。     

Molecular dynamics simulation of poiseuille flow in ultra thin film

The effect of a solid wall on Poiseuille flow of ultra thin film has been simulated by molecular dynamics for a simple Lennard-Jones fluid. Results showed that the velocity profile and flow are consistent with the prediction of the Stokes equations when the film thickness is considerably greater than the molecular ‘diameter’; that Poiseuille or hydrodynamic flow will be blocked by the solid walls, and the effective viscosity will increase as the film thickness corresponds more closely to only a few molecular diameters; and that when the film thickness is reduced to just the molecular diameter, the fluid molecules between the walls will be solidified or crystallised, and the Poiseuille flow will vanish. This may be one of the mechanisms of transition from hydrodynamic to boundary lubrication.     

Model and computer simulation of friction

A model, consisting of the stochastic formulae which describe the relationship between the friction coefficient and the parameters known to be significant in dry friction, is proposed for dry sliding friction between two randomly rough surfaces. The model considers the frictional phenomena which dominate in energy dissipation and which may occur simultaneously between contacting elements. The kind of interaction in a given spot of asperity contact depends on the local energy flux density. The effect of several parameters on the friction coefficient, the real area of contact, and the number of contact spots can be calculated with the FRI-SIM program. A comparison of the simulation and experimental data shows a convergence of results.     

A shear cell for the determination of the dynamic shear strength and flow behaviour of particulate materials

A new form of shear cell consisting of a torsional split-Hopkinson bar apparatus, modified to act as a new form of annular shear cell, has been developed and used to determine the dynamic shear strength and flow behaviour of particulate materials.     

基于失效—安全的磁流变液减振器阀的设计与仿真

首先,介绍了盘形缝隙式磁流变液减振器(MRD)阀的结构与原理.然后,以阀在零磁场下所需阻力系数的计算模型和盘形缝隙式MRD阀可调倍数的计算模型为理论基础,详细分析了基于失效-安全的盘形缝隙式MRD阀的设计步骤.最后,对通过理论计算得到的一种典型盘形缝隙式MRD阀的2个设计方案进行了仿真,并将其仿真结果与理论计算结果做了比较.     

The effect of branching on slip and rheological properties of lubricants in molecular dynamics simulation of Couette shear flow

Molecularly thin liquid films of alkane in extreme conditions in a thin film lubrication regime have been investigated. To get an insight into the effects of molecular architecture in the behaviour of these thin lubricant films we have studied six different molecules, mainly isomers of C₃₀. In this work the effect of branching on rheological properties and behaviour of lubricant film is examined. Our study shows viscosity and normal stress effects depend on the degree of branching. Dynamics of the molecules and their orientation are also affected by the degree of branching. A weaker layering near the wall is observed for branched molecules. Slip between the wall and lubricant film also was larger for branched molecules. Branched molecules had less tendency to change their orientation under the flow. The results obtained here could be helpful in designing new lubricants at the molecular level.     

颚式破碎机运动轨迹的计算机仿真研究

研究复摆颚式破碎机工作原理,建立动颚的运动模型,根据其模型开发了运动轨迹的计算机仿真软件,可以动态地显示动颚的运动情况,解出了进料口、出料口的最大水平和最大垂直位移及轨迹性能值,显示进料口、出料口位移的方向,解决了传统设计方法不能直观得到设计结果的问题,仿真结果为修改设计参数提供了依据。     

近钻头平衡钻井井底流场的计算机模拟

以PDC钻头为模拟对象,充分考虑钻头三维、旋转和喷嘴对称性等因素的影响,借助于CFD软件CFX5.6对近钻头平衡钻井井底的流场进行了模拟分析,并利用软件的后处理方式对井底的速度场分布作了精细的描述。对钻头的设计以及井底流场的真实情况的分析有着重要的指导意义。     

磁场复合电解加工流场分布特性的数值模拟

采用欧拉-欧拉多流体方法,对磁场复合电解加工的气液两相流进行了数值模拟,研究磁场作用下电解质流场流速、气泡体积分数分布等流体力学信息.仿真表明,静液状态时,在磁场的作用下,液相产生了流速,流速呈环状分布,气相呈搅拌状分布.入口添加流速后,在低流速下,液相速度仍呈环状分布,气相呈搅拌状分布;在较高流速下,液相和气相的分布与无磁场时的分布相近.     

LabVIEW application for computer simulation of the conversion technique of dual-slope analog-to-digital converter

The application designed in the LabVIEW environment for computer simulation of the work and simulation testing of analog-to-digital converter (ADC) with dual-slope conversion method is presented. The front panel contains graphical objects, permitting interactive communication with the user and the animation effects allow illustration of the ADC operation principle. The application permits the performance of virtual experiments thanks to the possibility of modification of the ADC parameters and the input signal parameters. The virtual electronic experiments presented in the paper simulate the real measurement processes. The application can be used for both education and specific research purposes.     

数控代码的计算机图形仿真

数控代码在正确性检验是一项极其重要的工作。计算机图形学和计算机仿真的飞速发展,使采用计算机图形仿真动画演示加工过程来检验数控加工程序的正确性成为最有效、经济、快的方法。作者利用ＶＣ＋＋６．０开发了相应的数控程序仿真软件,并就如何读取数控程序,分析、存取代码,及用动画演示切削加工过程方面的问题做了一些探讨。     

三阶段叶片式磁流变液减振器设计与磁路仿真

介绍了车用缝隙式阻尼型和孔式阻尼型叶片MRF减振器的磁路设计方案,并针对缝隙式阻尼型相对于孔式阻尼型间隙处磁感应强度小的不足,提出了采取切向放置铁芯的三阶段叶片式MRF减振器的设计。根据ANSOFT电磁场分析软件的仿真分析结果,该设计可增强缝隙处的磁场强度,并提高其均匀性。     

计算机模拟技术在生产计划安排中的应用

论述了计算机模拟技术在生产计划安排中的应用问题，建立了相关模型及约束条件，对计算机模拟过程进行了较为详细的说明，对于解决生产作业排序问题，计算机模拟被认为是一种有效的方法。     

圆筒形零件拉深压边力的数值模拟

采用板料成形模拟软件Dynaform对圆筒形零件拉深工艺过程进行了模拟,计算了理论压迫力,并与模拟结果进行了比较,分析了压迫力对成形件壁厚、应力和应变的影响。验证了理论计算压力在实践中是可以应用的。     

高温管式膨胀系统的计算机模拟

对2400kg／h高温管式膨胀系统,采用“小滑移”模型,并利用ANSYS／FLOTRAN CFD进行了数值模拟,得出整个模型流场的温度、速度及气固两相的分布,与实测值吻合较好。结果表明,提出的“分离考虑法”很好地解决了含水率和温度对烟丝混合气体变物性参数的交叉影响,得到的烟丝混合气体物性参数是正确的,可用于大输送量高温管式膨胀系统的计算机数值模拟。     

Direct measurement of bottom shear stress under high-velocity flow conditions

The objectives of the present research are to accurately measure bottom shear stress under high-velocity flow conditions. To achieve high-velocity flow conditions, a laboratory-scale flume has been specially built in which flow velocity can reach over 3 m s⁻¹. Also an instrument that can directly measure bottom shear stress has been developed and validated. Then, the flow resistance has been estimated by simultaneously measuring flow velocity and bottom shear stress. It appears that the shear stress is indeed proportional to velocity squared and also to Reynolds number. On the other hand, Manning's n value and the skin friction factor are more or less uniform across all experimental cases.     

安全假人的外形设计与计算机模拟

计算机辅助设计（CAD）已经成为了设计中重要的辅助手段。在设计中,通过计算机进行模拟、评价、分析和修改,增强了设计的可视化程度,降低了生产成本,大大提高了设计的品质和效率。鉴于人体模型的复杂性,安全假人外形采用的主要建模方式是善于建立生物模型3ds max中的多边形（polygon）建模。     

基于计算机仿真的带式输送机动态特性预测和控制

描述了带式输送机动力学现象，用有限元方法建立了带式输送机系统的运动微分方程。用仿真方法分析了带式输送机的动态特性，并与实测结果进行了比较。预测了紧急停车和起动过程中突然停电等工况下带式输送机的动态特性，并通过选择飞轮质量来达到控制和优化其性能的目的。     

基于Pro／E和ADAMS的双足步行机器人三维造型及仿真

随着科技的发展,机器人技术及仿真技术飞速发展。双足步行机器人相对于四足和多足机器人,其运动的稳定性和可靠性更难保证。现利用如今使用广泛、通用性强的Pro／E软件对人形机器人运动过程中最主要的支撑受力部位——腿部,进行三维的造型设计与装配,阐述其造型步骤及注意事项,并在零力矩判据下得出转动关节的转角值。为了更方便的研究机器人的稳定步行过程中各关节转角的插值,将腿部模型简化后倒入ADAMS中进行步行仿真实验,经观测其步行过程的平稳度,验证了关节转角插值的正确合理性。