集团级分布式产品数据管理系统的研究与实现

针对集团级分布式产品数据管理系统的需求,结合国产AVIDM 3．0系统,研究了大型高端产品数据管理系统的体系结构设计方法及实现技术,提出了一种基于域的分布式联邦产品数据管理系统架构及基于产品数据管理中间件软件平台的分层域内软件框架。该架构支持集中和分布两种部署模式,以满足大型集团松散耦合的层次组织关系及Down—to—top,Top—to—down,同级异地协同等信息交流的需求。基于项目的设计库、受控库、产品库和系统库概念,提出了电子文件的逻辑和物理全分布、项目级数据库全分布的产品数据存储方案,可满足海量数据存储要求。这些方法提供了一个从数据存储到应用服务全分布的解决方案,适用于支持大型复杂产品研制过程数据管理的高端产品数据管理系统的研制与开发。     

Computerized scaled cells to study the effect of additive ratios and concentrations on nodulation during copper electrorefining

Scaled copper electrorefining cells were designed, built and computerized to simulate as closely as possible industrial conditions at three Canadian copper refineries. The industrial dimensions of Falconbridge, Kidd Metallurgical Division, were considered while designing scaled cells. Anode width to cell width ratio, anode width to cathode width ratio, anodic surface to cathodic surface ratio, as well as electrolyte volume to cathodic surface ratio, which was about 60 L m^–2, were consistent with Kidd's industrial ratios. However, the cell design also allowed simulation of INCO's Copper Cliff Copper Refinery (CCCR) or Noranda's Canadian Copper Refinery (CCR). Electrorefining cells were 135.0 cm deep by 14.7 cm wide. Electrolyte flow rate was parallel to the electrodes. Electrolyte was circulated from the lower part of the electrorefining cells to the top where there was an overflow going to the electrowinning circuit. The equipment was computer controlled using Labview software. Experiments were conducted using this scaled electrorefining set-up to evaluate the effect of various ratios and concentrations of additives on nodulation during copper electrorefining under high current densities. Cathodic polarization curves, SEM micrographs, porosity analyses and copper grain analyses were used to characterize the cathodes produced.     

堆本体抗震试验动力相似关系推导与验证

为确保堆本体抗震试验中流体对流效应、脉冲效应和堆本体结构响应的准确性,需保证重力、流体与固体惯性力、结构弹性力和结构应变的相似性。本文从固体结构的振动方程、不可压牛顿流体的动力学方程、流固交界面的边界条件和环形柱体域内液体线性晃动的动力学公式出发,基于控制方程的量纲分析法,推导了考虑液体晃动效应的堆本体地震响应动力相似关系。基于上述相似关系建立了堆容器堆内构件和堆容器内自由液面流体域的缩尺模型,通过有限体积法分析堆容器堆内构件原型和缩尺模型中液体的晃动固有频率、晃动波高、压力以及液体晃动对堆容器支承裙的倾覆力矩。结果表明本文动力相似关系具有合理性和准确性,可用于堆本体缩尺模型的抗震试验研究。     

Effect of flow fields and humidification of reactant and oxidant on the performance of scaled‐up PEM‐FC using CFD code

The present study focuses on three‐dimensional two‐phase CFD investigation on scaled‐up proton exchange membrane fuel cell (PEM‐FC) for an active area of 100 cm² with different designs of serpentine and parallel flow configuration. The humidification of hydrogen and oxygen is varied from 10% to 100% to study the PEM‐FC performance. The numerical results of polarization curves predicted in this study have been numerically validated with that of the literature for both parallel and counter serpentine flow channels with active area of 24.8‐cm² PEM‐FC. Further upon validation, the numerical study is extended for scaled‐up PEM‐FC with active area of 100 cm² with different flow path designs to study its performance characteristics namely polarization curves, species concentration distribution, water content in the membrane electrolyte, and proton conductivity to evaluate the fuel cell performance. The three‐dimensional CAD models are created in SOLIDWORKS 10.0 and are discretised hexahedrally using finite volume method. The various governing equations namely conservation of mass, momentum, energy, species concentration, and electrochemical equations are solved numerically with the necessary boundary conditions using the CFD code. The novel design of straight zigzag flow path shows the better performance output over the other designs investigated which is having a higher power density of 0.3711 W/cm² for 100% relative humidity of reactant and oxidant.     

蒸汽驱低压比例物理模型改变注采井网试验

为了改变注采井网关系，在蒸汽驱高压比例物理模型和蒸汽驱真空比例物理模型基础，建立了蒸汽驱低压比例物理模型。利用试验温场图，可显著地观察到蒸汽驱油的宏观过程，为研究蒸汽驱工艺机理提供了较完善的物理模拟方法。     

基于SBFEM的心墙坝基座跨尺度精细应力分析

基座是连接混凝土沥青心墙坝心墙和防渗墙的关键部件,其受力特性对结构安全评价至关重要。通过四分树快速离散技术建立5种网格密度的跨尺度分析模型,采用非线性多边形比例边界有限元与传统FEM耦合计算方法,研究了基座结构在施工期的应力性态以及改善对策。结果表明：基座及周围土体网格尺寸对二者相互作用存在较大影响;随着网格的细化,基座应力极值将增大,且压应力极值最大相差约57.4%,拉应力极值相差约59.3%,但最终应力分布规律和数值均趋于收敛;在基座周围局部设置高塑性黏土区可有效改善基座应力状态。建议沥青心墙坝分析中基座网格尺寸宜为0.05~0.10 m,基座周围局部土体网格尺寸宜为0.1~0.2 m,黏土区宽度可取1.0~1.5倍的基座宽度。基于比例边界有限元的跨尺度分析方法可实现高效精细化建模和计算,能更合理地评价高坝防渗系统安全性。     

旋翼飞行机械臂系统的混合视觉伺服控制

旋翼飞行机械臂是一种具有强耦合特性的机器人系统,借助视觉进行自主作业还存在诸多问题,如实时深度估计、目标极易丢失以及目标笛卡尔空间模型重建等.本文针对传统的基于图像与基于位置的视觉伺服的缺陷以及系统自身欠驱动等问题,建立了运动学模型和提出了基于力平衡原理的动力学联合建模,并通过欧几里得单应性矩阵分解设计出旋翼飞行机械臂系统的混合视觉伺服控制方法,在图像空间控制平移、笛卡尔空间控制旋转,减弱了平移与旋转之间的相互影响实现解耦效果,改善了系统对非结构因素的抗扰性能和全局稳定性.通过仿真和实验检验了系统鲁棒性和算法优越性.     

Efficient wave propagation simulation on quadtree meshes using SBFEM with reduced modal basis

We apply a combination of the transient scaled boundary finite element method (SBFEM) and quadtree‐based discretization to model dynamic problems at high frequencies. We demonstrate that the current formulation of the SBFEM for dynamics tends to require more degrees of freedom than a corresponding spectral element discretization when dealing with smooth problems on regular domains. Thus, we improve the efficiency of the SBFEM by proposing a novel approach to reduce the number of auxiliary variables for transient analyses. Based on this improved SBFEM, we present a modified meshing procedure, which creates a quadtree mesh purely based on the geometry and allows arbitrary sizes and orders of elements, as well as an arbitrary number of different materials. The discretization of each subdomain is created automatically based on material parameters and the highest frequency of interest. The transition between regions of different properties is straightforward when using the SBFEM. The proposed approach is applied to image‐based analysis with a particular focus on geological models. Copyright © 2016 John Wiley & Sons, Ltd.     

Numerical investigation of similarity laws for blast simulation: Open-field propagation and interaction with a biomechanical model

In a military context, blast loadings are encountered, with more or less severe consequences on structures in interaction with a shock wave, which travels in a field. With a need of protecting the fighter, the understanding of this physical dynamic phenomenon is of extreme importance to avoid body trauma induced by the primary blast. In this context, this study explores simulations of blast loading, and its interaction with a human torso biomechanical model previously developed, based on referenced experiments from the literature. The concept of similarities is also studied (peak pressure equivalence for long distance and large explosive mass and short distance and small explosive mass). Validations of numerical results are conducted using experimental data from the literature in terms of pressure peak as a function of scaled distance, and also in terms of pressure time history in the biomechanical model. Good agreement between the numerical results and the experimental peak pressure is achieved.     

基于伸缩梯度投影的天文图像复原改进算法

在地基天文观测中,克服大气湍流造成的图像模糊是获取高分辨率天文图像的关键.反卷积是图像复原过程中的重要步骤,基于伸缩梯度投影的反卷积算法具有较高的复原精度和处理效率,且鲁棒性好,适用于天文图像的复原.但由于实际应用中清晰图像是未知的且存在噪声的干扰,该算法存在着无法自行停止迭代的弊端,限制了其应用.结合图像无参考质量度量给出一种可自动停止迭代的改进算法.仿真表明:改进的算法对最优点判断较为准确,能够运用于实际天文图像处理.