户外电子设备箱结构设计及应用

基于户外机箱结构设计的特点,阐述了一种电子设备结构设计流程。论述了结构总体方案设计要点、密封性设计、电磁兼容性设计、三防设计、维修性设计、热设计,给出了密封条压缩量、波导通风板结构尺寸的计算公式。运用此设计流程,设计了一种户外电子设备,详细分析了产品的结构设计。产品样机各项指标满足设计要求,验证了该设计方法的工程应用性。     

现代设计方法在机电产品中的应用

本文简单介绍了现代设计方法的一般概念与市场需求,简要提出了现代设计对机电产品的指导性作用,结合现代设计方法的特点,从绿色设计、并行设计、可靠性设计、虚拟设计、智能优化设计、模糊设计几个方面系统地阐述了现代设计方法在机电产品中的应用。     

共用性设计及其在工业设计中的应用

阐述了共用性设计的概念,分析了共用性设计产生的原因,探讨了共用性设计的原则。在此基础上,分析了共用性设计和工业设计的关系。以洗衣机为例,说明共用性设计在工业设计中的应用。     

基于设计结构矩阵的起重机设计过程建模研究

把设计结构矩阵和设计参数指标结合起来,扩展了设计结构矩阵表达的信息量,较全面地反映设计开发过程.用此扩展的设计矩阵分析了桥式起重机小车的设计开发过程,将其设计过程模块化;通过设计活动重组,降低了原有设计过程的耦合程度.     

不确定性设计优化理论与方法研究

系统地开展了不确定性设计优化理论与方法研究,定义了设计不确定性、设计稳健性和设计可靠性等概念,阐述了不确定性设计优化理论体系框架,建立了不确定性设计优化模型,提出了解决不确定性设计优化建模、求解和计算复杂性问题的有效途径.     

设计思维研究现状及发展趋势

为研究设计者的设计思维状态,探索设计的内在认知规律,从而为系统指导设计尤其是创新设计奠定基础,探讨了设计思维的概念,从设计思维的理论基础和模型构建、外在表现和影响因素等方面分析和探讨了设计思维理论研究现状,阐述了设计思维的研究技术和方法,在此基础上探讨了设计思维进一步的发展趋势,为理解设计的本质思维规律、促进设计创新的产生提供了有益的参考.     

基于公理化设计矩阵与设计结构矩阵集成的研究

分析公理化设计与设计结构矩阵的优缺点,利用二者的优势互补性,提出了公理化设计矩阵与设计结构矩阵集成思想,详细研究了公理化设计与设计结构矩阵集成的方法与步骤,并提出了基于公理化设计矩阵与设计结构矩阵集成的框架模型,促成产品功能与结构的同步演化;开发了计算机辅助概念设计系统以支持公理化设计与设计结构矩阵的集成;最后以自动化物料运输系统为实例,详细阐明了公理化设计矩阵与设计结构矩阵集成的过程.     

设计意图驱动的产品形态设计方法

为减小用户和设计师对产品形态方案的认知差异,将产品形态设计中的设计意图分为设计需求意图、设计编码意图和设计解码意图,建立了设计意图模型,构建了以满足用户需求意图、体现设计师设计编码意图及减小用户解码与设计师编码之间差异为目标的设计意图模型求解算法,探讨了设计意图驱动的产品形态设计过程,研究了基于交互式遗传算法的设计意图求解方法。以家用轿车前脸形态设计为例,分别进行了设计需求意图获取与映射、设计编码意图表达以及交互遗传解码研究,验证了所提方法的有效性。     

汽车整车逆向设计内容总结及正向设计流程探讨

分析了逆向设计与正向设计的差异,给出了逆向设计的一般流程,并结合汽车设计特点,论述了汽车逆向设计对于企业积累设计知识、明确产品定位、实现快速开发的重要性,在此基础上,将汽车逆向设计工作按内容不同细分为几个阶段,并概括总结了汽车逆向设计各阶段的主要内容。分析指出了如果汽车设计开发中逆向和正向设计之间流程设置不当,将不可避免地会给汽车正向设计带来隐患,并给出了融合汽车正向设计与标杆车逆向设计的流程建议。     

柴油机曲轴的公理化设计

通过对公理化设计基本概念和设计过程的研究 ,提出了将公理化设计思想运用于柴油机曲轴设计的方法 ,建立了应用公理化设计进行曲轴设计的系统框架 ,开发了在UGII软件平台上进行公理化设计的软件系统。     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.     

OUT-OF-PLANE COMPRESSIVE PROPERTIES OF HEXAGONAL PAPER HONEYCOMBS

The compressive behaviour of paper honeycombs is studied by means of an experimental analysis. Experiment results show how geometry aspects of hexagonal paper honeycombs,e.g. the height of paper honeycomb,the thickness and length of honeycomb cell-wall,the drawing ratio of hexagonal honeycomb,affect the compressive properties of the paper honeycombs. It is in good agreement with the theory model. The constraint factor K of the critical buckling stress is mainly determined by the length of honeycomb cell-wall. It can be described as K=1.54 for B type paper honeycombs and K=3.32 for D type paper honeycombs. The plateau stress is the power exponent function of the thickness to length ratio of honeycomb cell-wall,and the experiment results show that the constant is 13.2 and the power exponent is 1.77. The research results can be used to characterize and improve efficiently the compressive properties of paper honeycombs.     

A method for TEM visualization of the extracellular matrix three-dimensional organization in tissues

A method for obtaining high-resolution three-dimensional images of the extracellular matrix organization in tissues is described. It consists of TEM observation of rotary-shadowed platinum–carbon replicas obtained from critical-point dried resinless sections of polyethylene glycol-embedded specimens. The procedure is simple and rapid, with high rates of sample recovery. An example of its application to EM immunocytochemistry (fibronectin localization) is presented. The utilization of the method to demonstrate cell-extracellular matrix relationships, and its limitations in the study of cells are discussed.     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.     

DESIGN AND ANALYSIS OF NOVEL ACTIVE ACTUATOR TO CONTROL LOW FREQUENCY VIBRATIONS OF SHAFT SYSTEM

Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.     

Effects of prebuckling deformations on the elastic flexural-torsional buckling of laterally fixed arches

The effect of the prebuckling in-plane deformations on the elastic flexural-torsional buckling of laterally fixed circular arches is studied in this paper. The finite strains and the energy equation for the flexural-torsional buckling of arches have been derived based on an accurate orthogonal rotation matrix. A closed form solution for the elastic flexural-torsional buckling resistance of laterally fixed arches in uniform bending, including the effects of the prebuckling deformations, is obtained. It is found that the notion that the prebuckling deformations increase the flexural-torsional buckling moment of an arch or of a beam is not necessarily correct for a laterally fixed arch or beam in uniform bending, in deference to a laterally pinned arch. When a laterally fixed arch is subjected to positive uniform bending, the effects of the prebuckling deformations decrease the buckling moment, and the reduction of the buckling moment increases with an increase of the included angle and of the out-of-plane slenderness ratio of the arch. When a laterally fixed arch is subjected to negative uniform bending, the effects of the prebuckling deformations decrease the absolute value of its buckling moment when the included angle is very small, but increase the absolute value of the buckling moment when the included angle exceeds a certain value. The increase in the absolute value of the buckling moment increases with an increase of the included angle and of the out-of-plane slenderness ratio of the arch. When the ratio of the out-of-plane to the in-plane second moments of area of the cross-section is not small, both the reduction of the buckling moment of a laterally fixed arch in positive uniform bending and the increase of the buckling moment of a laterally fixed arch in negative uniform bending, are substantial.     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

PHENOMENON OF CARVED DRIVING WHEELS

A newly found phenomenon of carved driving wheels of a rear-wheel-drive tractor used in an airport is discussed. The circum of every driving wheel is damaged at three regions,which distribute regularly and uniformly. Everyday,the tractor tows a trailer which are times heavier than the tractor,and moves on the same road in the airport. The phenomenon is explained by the torsional self-excited vibration system of the powertrain. The simplified torsional vibration system is discribed by a 2-order ordinary differential equation,which has a limit circle. Experiments and numerical simulations show the followings: Because of the heavy trailer,the slip ratio of the tractor’s driving wheels is very large. Therefore,there is severe torsional self-excited vibration in the tractor’s drivetrain,and the self-excited vibration results in severe and regular fluctuations of the rear wheel’s velocity. The severe fluctuations in velocity fastens the damage of the driving wheels. At the same time,the time interval in which an arbitrary point in the circum of the driving wheel contacts with the road twice is two times more than the period of the torsional self-excited vibration,and this times explained the existence of three damaged regions. At last,it points out that the phenomenon can be avoided when the torsional damping is large enough.     

The simulation and error analysis of raindrop size distribution obtained by micro rain radar

Observation of raindrop size distribution( DSD) with a vertically pointing micro rain radar( MRR) has important significance in the precipitation measurement field. The Mie scattering of large particle,vertical wind and air turbulence have great influences on the retrieval of DSD measured by MRR. This paper simulates the process of how three factors affect the inversion of DSD and the calculation of other precipitation parameters,then makes the errors analysis. Because the wavelength of MRR is 12.5mm,M ie theory is more suitable for the precipitation particle than Rayleigh approximation,w hich may cause the underestimation of number density of small droplets and the overestimation of that in middle field. The vertical wind results in inaccurate estimation of particle terminal velocity,so the diameter is measured with some errors by empirical relationship,w hich affects the calculating accuracy of radar reflectivity and rain rate. Air turbulence can broaden the pow er spectral density,of which the impact on the inversion of DSD are concentrated in small droplets field. Then the measured data from MRR is analyzed and the results prove the impacts of those factors. Finally,according to the analysis and application limits,the prospect of the future research trend of particle size distribution is conducted.     

MODELING METHOD FOR PRODUCT STRUCTURE MAPPING BASED ON REVERSE SOLVING OF LOCUS AND MOTION

Aiming at the problem of structure design in reverse-design of mechanism, a structure mapping method based on reverse solving of locus and motion (RSLM) is presented. The mechanism scheme meeting the requirements of geometric and structural features is obtained through RSLM. The element instance subsets related to component are established based on the element type mapping, pair structure type mapping and design knowledge mapping between components and elements layer by layer. The assembly position mapping of elements is established based on the topological structure information of mechanism scheme, and the product modeling of structure mapping is realized. The algorithm program and prototype system of product structure mapping based on RSLM are developed. Application samples show that the method implements the integration of scheme design, assembly design and structure design, and modeling for product structure mapping based on RSLM. The feasibility of assembly is analyzed in scheme design that contributes to reducing the design error, and raising the design efficiency and quality.