基于新型环保车建模过程的多维数据格式转换研究

以新型环保车为例,首先介绍了该产品的结构,分析了该产品的建模思路;其次对相关三维软件及其数据格式进行了初步探讨;最后,深入研究了新型环保车的建模和数据格式转换问题.该研究是对当前主流三维软件数据格式转换问题的一次系统性探讨,为产品的快速建模和设计规划提供了科学借鉴.     

Investigation of erosion-corrosion mechanisms of UNS S31603 using FIB and TEM

Accelerated wear due to synergy during erosion-corrosion of UNS S31603 is extremely complex. It is this reason that current modelling approaches fail to accurately model the physical mechanisms in this wear process. The objective of this work was to perform FIB and TEM analysis on UNS S31603 to investigate the subsurface deformation mechanisms and microstructural changes in the material during erosion-corrosion. FIB investigation revealed a decrease in grain size at the surface and a change in grain orientation towards the impact direction. Networks of cracks were observed near the surface which is believed to be caused by work hardening of the material which increased the material susceptibility to fatigue cracking. Folding of lips is also proposed as an important mechanism for subsurface wear. The large amount of strain imposed on the material also induced martensitic phase transformation. Fragmented erodent particles and oxide film were found embedded into the material which caused formation stress concentrated regions in the material and contributed to crack initiation. A composite structure is formed consisting silicon oxide sand particles and chromium oxide film along with the martensitic phase transformed metal. The corrosive environment is also believed to have played a significant role in the initiation and propagation of cracks. Crack initiation and propagation due to the mechanical and electrochemical processes enhances the material mass loss as the crack networks coalesce and subsequently cause material spalling. Physical models are developed based on these observations to explain the microstructural changes and synergistic mechanisms.     

基于性能驱动的可拓数据挖掘产品配置设计方法研究

针对现有产品配置设计方法中对客户性能需求研究的不足,结合可拓数据挖掘方法提出了基于性能驱动的可拓数据挖掘产品配置设计方法研究。首先通过对客户个性化需求的定量与定性化分析,建立客户需求分析模型;其次对配置模型的参数知识进行可拓知识挖掘,并对产品布局结构的变换阈值知识进行相互匹配与矛盾问题消解,建立变换消解模型及满足客户需求的可变换阈值解空间;然后在此基础上,对产品配置过程中的知识组合矛盾问题,进行基于可拓数据挖掘的传导变换,求解出满足客户需求的配置解空间;最后基于Visual C++6.0、Solidworks等平台开发软件建立了产品的快速配置系统,通过实例测试,验证了该方法的准确性和有效性。     

Investigating material removal rate and surface roughness using multi-objective optimization for focused ion beam (FIB) micro-milling of cemented carbide

Cemented carbide has been investigated as a useful material for the fabrication of micro devices. Focused ion beam (FIB) micro-milling has been found to be one of the most appropriate methods for the fabrication of micro devices. The experimental FIB micro-milling on cemented carbide have been conducted according to the L₁₆ orthogonal array of Taguchi technique. Beam current, extraction voltage, angle of beam incidence, dwell time and percentage overlap between beam diameters have been considered as process variables of FIB micro-milling in experimental design. Material removal rate (MRR) and surface roughness have been determined experimentally for FIB micro-milling of cemented carbide and beam current has been identified as the most significant parameter. The minimum surface roughness of 5.6 nm has been reported on cemented carbide, which is not a usual practice to achieve on such polycrystalline material, and hence it may be considered as a significant research contribution. Maximum MRR of 0.4836 μm³/s has been reported. Moreover, genetic algorithm toolbox of MATLAB has been utilized for multi-objective optimization between MRR and surface roughness. The corresponding optimum values of MRR and surface roughness for multi-objective optimization have been represented by pareto optimum solution generated by genetic algorithm. The research work presented in this paper determines the setting of process parameters of FIB micro-milling for achieving a specific combination of MRR and surface roughness on cemented carbide.     

面向制造型企业数据仓库的数据模型设计

引用了数据仓库、数据集市的概念 ,探讨了以压缩机厂为背景的面向制造型企业数据仓库的系统结构和数据模型设计。     

Evolution of residual stress and crack morphologies during 3D FIB tomographic analysis of alumina

Three‐dimensional focused ion beam (FIB) tomography is increasingly being used for 3D characterization of microstructures in the 50 nm–20 μm range. FIB tomography is a destructive, invasive process, and microstructural changes may potentially occur during the analysis process. Here residual stress and crack morphologies in single‐crystal sapphire samples have been concurrently analyzed using Cr³⁺ fluorescence spectroscopy and FIB tomography. Specifically, maps of surface residual stress have been obtained from optically polished single‐crystal alumina [surface orientation (1 ī 0 2)], from FIB milled surface trenches, from Vickers micro‐indentation sites (loads 50 g–300 g), and from Vickers micro‐indentation sites during FIB serial sectioning. The residual stress maps clearly show that FIB sputtering generates residual stress changes. For the case of the Vickers micro‐indentations, FIB sputtering causes significant changes in residual stress during the FIB tomographic serial sectioning. 3D reconstruction of the crack distribution around micro‐indentation sites shows that the cracks observed are influenced by the location of the FIB milled surface trenches due to localized stress changes.     

Investigation of Submicron Linewidth Direct Deposition for High-Density IC Chip Modification by Focused Ion Beam

Submicron linewidth direct deposition is a challenge for focused ion beam technology. A high-resolution image is the first necessary condition in order to obtain such a fine deposited line. Besides this, dwell time, X and Y pixel space, beam current, residual gas pressure, and work chamber vacuum are also important parameters for the deposition process. The quality of the deposited line depends on reasonable selection and optimisation of these parameters. Based on influence factor analysis, suitable parameters are arrived at for submicron linewidth deposition. The procedure was tested by its application of high-density IC chip modification.     

利用VB进行AutoCAD图形格式的批量自动转换

介绍了一种利用VB对AutoCAD进行二次开发,将DWG文件批量自动转换为WMF文件的方法.     

数据采集卡在流量标定装置控制系统改造中的应用

介绍了数据采集卡在流量标定装置控制系统改造中应用的关键技术。     

基于STL文件格式的线框模型算法的研究与实现

介绍了基于 STL文件格式的线框模型算法 ,该算法是通过寻找 STL文件每个平面的轮廓环设计的 ,同时给出了一个该算法在基于 STL文件格式的快速模具设计系统中的应用例子     

基于组件的AutoCAD图形格式转换及其网络传输

讨论了在组件中实现AutoCAD的连接、AutoCAD图形格式转换及其网络传输的实现方法。通过使用组件,可以在Web环境下运用AutoCAD进行设计。     

Studies on ZDDP Thermal Film Formation by XANES Spectroscopy, Atomic Force Microscopy, FIB/SEM and 31P NMR

X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of thermal films on steel samples, which were generated from a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive. These films were formed at 150 °C by immersing steel coupons in ZDDP oil solutions. The phosphorus L-edge XANES spectra show that these films are composed of polyphosphates, unreacted ZDDP and other thiophosphate intermediates. Phosphorus K-edge FY XANES was used to monitor the thickness of these films, and the data are consistent with thickness derived by focussed ion beam (FIB) milling and SEM imaging. The sulphur K-edge TEY and FY XANES spectra show that these films are composed of different sulphur components, which depend upon the formation times. The surface morphology of these films was investigated using atomic force microscopy (AFM). These images show that the surface morphology of the thermal films changes with the formation time. 31P NMR spectra show that both primary and secondary ZDDP decomposes gradually at 150 °C.     

零部件数据处理平台研究

零部件的数据信息来源多,数据格式不同。提出了针对零部件数据处理的数据清洗、数据转换、数据验证及数据分析算法并加以实现。     

Solidworks中齿轮二次开发的数据处理

通过应用数据离散化和数据程序化对基于Solidworks齿轮二次开发的数据处理进行研究.     

基于互联网的公开数据挖掘研究

研究了数据挖掘在互联网上公开数据的收集与处理中的应用.将数据挖掘技术应用于数据收集、数据管理、数据分析等各个阶段,从而形成有用的情报,在不同层次上促进了情报工作的深入与相应问题的解决.     

Registration and Data Merging for Multiple Sets of Scan Data

It is generally necessary in 3D scanning to divide a wrap-around object into several regions, each of which is measured individually. A series of pre-processing procedures must be implemented to prepare the data for use for surface reconstruction. Registration is a procedure for unifying the coordinate systems for multiple sets of scan data. Three registration algorithms, 3 points to 3 points, 3 spheres to 3 spheres and 3 planes to 3 planes, are proposed to suit different applications. Data merging is a procedure for removing overlapping data for multiple sets of scan data and for merging them into one set. A data search algorithm, based on triangulation, is com-bined with a few merging rules to merge the data in terms of different needs. Several experimental results are presented to demonstrate the feasibility of the proposed algorithm.     

Point Data Reduction Using 3D Grids

Reverse engineering refers to the process of obtaining a CAD model from an existing physical part. Advances in laser scanning technologies have facilitated this process by sampling part surface data with speed and accuracy. With the help of this technology, it is now possible to acquire the geometry of a part having complex and freeform surfaces. However, it creates the burden of large amounts of point data which must be manipulated, therefore, data from a laser scan must be significantly reduced to proceed with the computations and to lower the storage requirement. Many point data reduction methods for image processing have been developed in the past. However, there is little published work on laser-scanned data, and what exists focuses only on 2D point data. This paper presents a data reduction method that reduces the amount of 3D point data using part geometry information. The method reduces the point data, based on normal values of points using 3D grids. The method is applied to two sample models and the results are discussed.     

数据筛选技术在数据采集系统中的应用

本文介绍了数据库中的数据筛选技术在数据采集系统中的应用方法，使得筛选后的数据量少而且还能满足数据采集精度的要求，并给出了VB环境下采集数据筛选的具体的程序实现。     

CS File – An Improved Interface Between CAD and Rapid Prototyping Systems

The STL file, which is de facto standard for the rapid prototyping industries, has too large a file size. This paper proposes an improved interface between CAD and rapid prototyping systems, i.e. a CS (compressed STL) file that has very low data storage redundancies and is completely compatible with the STL file. The CS file is about a quarter of the size of the original binary STL file, without any model information loss. This is very suitable for file transferring via the Internet. Removing coordinate data of duplicate vertices, bit-compression technology, and a comparison of the size and compressed performance of the STL and the CS are also discussed. ID="A1"Correspondance and offprint requests to: Dr Li-Chao Zhang, Rapid Prototyping Building, State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, PR China. E-mail: elegantteac@yahoo.com     

Error Compensation for Three-Dimensional Line Laser Scanning Data

In this paper, the problem of compensation of 3D line laser scanning data for improved inspection accuracy is addressed. This problem is important, as a 3D line laser scanner is about one order less accurate than a touch probe. The approach taken is to compensate through error characterisation. In other words, a software compensation is performed, instead of a hardware compensation, which is probably more expensive. To do so, the errors associated with a 3D line laser scanning system are first characterised. With error characterisation, an empirical formula is obtained relating the errors to the influencing factors including the projected angle and the scan depth. This empirical formula is used to compensate for the digitised surface data obtained by the corresponding laser scanning system. The results show that the proposed approach effectively improves inspection accuracy.