确定冲模压力中心的计算机作图法

提出基于AutoCAD软件的确定冲模压力中心的计算机作图法 ,这种方法理论严谨 ,结果准确 ,比原有的计算法和作图法简捷、快速 ,具有应用推广价值     

A novel optimal working process in the design of parametric progressive dies

The objective of this study was to establish a genetic algorithm to solve the problems of ranking the working steps in progressive dies. The working area of punch in working station of progressive die was regarded as the basic reference for gene coding. The moment generated from punch to mold center is defined as fitness function. A common method, remainder stochastic sampling with replacement (RSSR), was adopted to carry out gene reproduction process calculation. We combined the fixed crossover rate and mutation rate to be the crossover and mutation process calculation basis and then obtained the optimum process in which the total moment relative to the mold center was at a minimum. Finally, we developed a “dimension-driven” Windows graphical program written in Visual C++ as an interface for parametric input and communicated with the ACAD software through a DXF file. This system is expected to be a helpful tool for designers facing demands for higher quality, lower cost and shorter delivery time for sheet metal products.     

A new data analysis method to determine pesticide concentrations by cyclic voltammetry

Determining pesticide concentration is very important for safe agricultural products. In this study, a new data analysis method was developed to determine the concentration of Carbofuran pesticides by cyclic voltammetry. The peak current and two specific area indexes calculated from the cyclic voltammetry curves served as the dependent variables. The concentrations of Carbofuran pesticides were used as the independent variables. The inverse calibration equation was used to evaluate the predictive performance. The results indicated that the numeric values of the cyclic voltammogram area ranging from 0.5 to 0.9 V were the best index value of pesticide concentration. The precision of this index was better than that of others two indexes. The accuracy of the determination technique with the calibration equation was within 5 ppm by the adequate calibration equation.     

多波长消光测粒技术的一种改进方法

:在详细研究现有多波长消光测粒技术的基础上 ,分析了各个波长下各透射光强之间的内在联系 ,并提出消光测粒技术在具体应用中的一种新的改进方法。     

A new method to determine the number of experimental data using statistical modeling methods

For analyzing the statistical performance of physical systems, statistical characteristics of physical parameters such as material properties need to be estimated by collecting experimental data. For accurate statistical modeling, many such experiments may be required, but data are usually quite limited owing to the cost and time constraints of experiments. In this study, a new method for determining a reasonable number of experimental data is proposed using an area metric, after obtaining statistical models using the information on the underlying distribution, the Sequential statistical modeling (SSM) approach, and the Kernel density estimation (KDE) approach. The area metric is used as a convergence criterion to determine the necessary and sufficient number of experimental data to be acquired. The proposed method is validated in simulations, using different statistical modeling methods, different true models, and different convergence criteria. An example data set with 29 data describing the fatigue strength coefficient of SAE 950X is used for demonstrating the performance of the obtained statistical models that use a pre-determined number of experimental data in predicting the probability of failure for a target fatigue life.

     

Development of a geometric modeling tool for rectangular drawbeads in draw dies

This paper presents the development of a geometric modeling tool for rectangular drawbeads on curved binder surfaces in draw dies. The developed tool provides a fully automated and robust modeling procedure for the geometry of the drawbeads. Given a bead curve on the binder surface, the section profiles are computed at the points on the bead curve. The section profiles and the given bead curve make the three-dimensional drawbead as a sweep solid. The sweep solid is mounted and combined on the binder surfaces. Finally, the shoulder and exit edges of the drawbead are rounded. The value of the rounds is easily modified, because the rounding is the last procedure of the modeling process. The developed tool was tested and it was verified that it helps to reduce the modeling time and increase the quality of the drawbeads.     

黑板原理在级进模工步排样方案构造系统中的应用研究

首先对黑板原理及相关技术进行了简单阐述。全文着重介绍了构造复杂级进模工步排样方案生成系统中，黑板模型的建立，并论述了该模型的推理机制。随后，还介绍了黑板结构的实现，通过原型系统的开发，论证了该理论在系统实现中的合理性和优越性。     

级进模工步设计的专家系统实现方案

提出级进模工步设计的专家系统实现方案,利用AutoCADR14提供的ObjectARX获取冲裁件图形信息,建立起基于关系型数据库的知识库和事实库,提出了分级推理、二次排序的推理机制,模拟了专家的设计过程。     

A calorimetric method to determine water activity

A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg(-1) to 3 mol kg(-1) and seven saturated aqueous salt solutions (LiCl, MgCl(2), NaBr, NaCl, KCl, KNO(3), and K(2)SO(4)) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities.     

Development of a process sequence determination technique by fuzzy set theory for an electric product with piercing and bending operation

This paper describes a research work to develop a computer-aided design of a product with bending and piercing operations for progressive working. The approach to the system is based on knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results and the empirical knowledge of experts in the field. The system has been written in AutoLISP with AutoCAD on a personal computer and is composed of three main modules: input and shape treatment, flat pattern layout, and strip layout modules. The system is designed by considering several factors, such as piercing and bending sequence by fuzzy set theory, complexities of blank geometry, punch profiles, and the availability of press equipment. The strip layout module generates the 3D strip layout drawing with the punch profiles for the external area of a product according to the results of the FVM set. The system could serve as a valuable system for experts and as a dependable training aid for beginners.     

链环钩冷弯模具及自动卸料机构的研制

为提高链环钩生产效率，采用一次弯曲成形的工艺方案，并研制了带有自动卸料装置的弯曲模具。该模具应用于大批量生产中可显著降低制造成本。     

Development of a new method for joint damping identification in a bolted lap joint

Mechanical joints have considerable effects on dynamic behaviour of machine tools; thus, joint damping identification is important in studying the dynamics of mechanical structures. Due to the difficulties in analysis of microslip friction, the experimental prediction of microslip joint dynamics is of great importance. In this study, a new experimental approach is proposed to determine the damping of bolted lap joints. Because of the complex nature of the mechanical joints, the lap joint is isolated through the addition of a mechanical resonator, which consists of a lumped mass and spring, to the bolted structure. The frequency response function (FRF) of this system is used for joint damping identification. This approach is used for bolted structures under both translational and torsional excitations and overcomes difficulties associated with slip boundaries identification in the joint interface. The method is verified by comparing the obtained results with those of the hysteresis loop approach.     

Computerized method to determine crystal orientations from Kikuchi patterns

A computerized method for determining crystal orientations from Kikuchi line patterns is described. The method is rapid and easy to use. When the Bravais lattice is known, the user need only specify a reference direction and the coordinates of the origin and of two points on each of six Kikuchi lines (three pairs). The programs yield the hkl indices of the Kikuchi lines, the beam direction, and the rotation matrix relating the crystal to a chosen reference frame. This rotation matrix can be used for various purposes, e.g., to specify an angle of rotation around a chosen axis or to calculate the misorientation between any two crystals.     

一种新型石油管材高温高压三点弯压力釜设计

为模拟油井管及接头在深井中受到的高温、高压、拉伸/压缩等复杂工况,设计了一种新型石油管材高温高压三点弯压力釜装置。提出了依据爆破压力设计关键尺寸,再通过有限元法进行强度校核的设计模式。创新设计了釜体端部密封结构及三点弯导杆密封结构。对新设计的高温高压三点弯压力釜进行了油井管三点弯试验。试验结果表明:新型高温高压三点弯压力釜强度、刚度符合设计及使用要求,密封可靠,三点弯机构满足试验需求。得到结论:该设计有效地解决了高温高压环境石油管材施加弯曲载荷的难题。     

A systematic method for studying a manufacturing enterprise to determine the possibilities for integration

There is a need to develop a framework for integration in manufacturing. This paper gives a framework for an ‘integration audit’, i.e. an approach which identifies areas for integration and produces an integration profile which summarizes the findings. An integration audit takes the form of asking and answering questions. A progressive approach to integration is recommended which (1) establishes performance measures, (2) integrates the material flow system, (3) plans integration inside each management function, (4) plans the dataflow between functions and (5) organizes the system by assigning responsibility to individuals for different sets of tasks.     

冲裁模CAD系统的开发研究

开发了冲裁模CAD系统,建立了零件图形输入、冲裁件优化排样、工艺分析与设计、结构设计等模块。采用该系统可大大提高冲模设计效率和可靠性。     

新型数字混沌密钥序列发生器的周期扩展方法及实现

混沌的良好统计特征和初值的敏感性适合加密系统设计,但由于数字混沌是在有限精度下进行的,导致混沌系统特性的退化,尤其是输出序列呈现出周期性,不利于加密系统组建.针对数字混沌序列的短周期现象提出改进方案,这种新系统输出的序列周期可根据加密需要进行设定,弥补数字混沌短周期现象,并有更加良好的抗多径干扰与多址干扰的能力.使数字混沌密钥序列发生器可安全应用到加密系统中.根据理论,利用FPGA设计了其硬件电路并应用在实际项目中.