叶切面最大厚度的数值计算方法

叶切面最大厚度计算是螺旋曲面加工准备过程中必要的环节.探讨适合于叶切面最大厚度的数值计算方法.详细介绍叶切面厚度数值计算所包括的叶切面最大厚度区域搜索、叶切面最大厚度精确计算过程.     

机械基础虚拟实验室的开发及应用

简要介绍了虚拟实验室在国内外的研究现状,分析了机械基础虚拟实验室的基本要求,探讨了利用仿真技术对机械基础虚拟实验室的开发过程,以组合机构为例介绍了机械基础虚拟实验室的应用。     

电涡流传感器互换性的研究

本文介绍了电涡流传感器互换性的概念及提高互换性的思路和方法,强调了工艺这一关键因素。这些对其它类型的传感器同样有着一定的指导意义。     

Geometrical method of selection of features of diagnostic signals

The paper presents the method of selection of features of diagnostic signals relying on the geometry of observation space. The method presented here uses two criteria of ability to separate (isolate) classes of an object's state: the criterion of average scatters and the original criterion of number of prototypes of classes. The method can be successfully used for initial analysis of input data to a neural network dealing with recognition of patterns and classification of an object's state. It also possible to use the algorithm presented here for determining the prototypes of classes needed for creating the training set for the neural network.     

在线修正大型起重机剩余寿命的研究

基于修正Miner疲劳损伤累积理论,采用在线修正的名义应力估算疲劳寿命的方法,设计了一套大型起重机在线寿命预测系统。通过数据的实时测量对剩余寿命进行修正,更好地结合实际,提供了一种准确、实用的预测起重机安全剩余寿命的新手段。     

计算机能够识别的机构组合模型

为实现计算机辅助机构组合，针对机构组合模式、组合相容性和组合方法进行了研究和探讨，构建出一种计算机能够识别机构组合模型。根据欲通过机构组合获取机构解功能元的具体要求，将机构组合模型分为基于“最小粒度功能元”和基于“非最小粒度功能元”的机构组合模式，两种组合模式均已程序化，并成功地应用于机械自动化组合软件系统研制中，实现了机构间的自动化动态重组。为实现机械运动方案智能CAD奠定了良好基础。     

面向绿色制造的产品模块化设计研究综述

阐述了绿色产品生命周期的涵义,分析了绿色产品生命周期各阶段的特性及关联关系,对目前存在的绿色模块化设计技术和方法进行了分类总结。根据绿色产品生命周期各阶段研究侧重点不同,将目前绿色制造模块化设计归纳为面向产品生命周期模块化设计、绿色设计模块化设计、环境意识模块化设计、再制造模块化设计、可拆卸模块化设计、维修模块化设计、回收模块化设计、重用模块化设计及其他模块化设计,并对其相应的模块化设计方法进行了综述分析。最后展望了今后的研究趋势。     

膨胀套导向机构的设计

通过分析膨胀套在实际使用产生滑移受阻现象、卡死现象原因的实质,并在分析产生问题原因的基础上提出了改进措施即：增加导向机构。     

Natural frequencies of vibration of a class of solids composed of layers of isotropic materials

In a recent paper, the Ritz method with simple algebraic polynomials as trial functions was used to obtain an eigenvalue equation for the free vibration of a class of homogeneous solids with cavities. The method presented is here extended to the study of a class of non-homogeneous solids, in which each solid is composed of a number of isotropic layers with different material properties. The Cartesian coordinate system is used to describe the geometry of the solid which is modelled by means of a segment bounded by the yz, zx and xy orthogonal coordinate planes and by two curved surfaces which are defined by fairly general polynomial expressions in the coordinates x, y and z. The surface representing the interface between two material layers in the solid is also described by a polynomial expression in the coordinates x, y and z. In order to demonstrate the accuracy of the approach, natural frequencies are given for both a two- and three-layered spherical shell and for a homogeneous hollow cylinder, as computed using the present approach, and are compared with those obtained using an exact solution. Results are then given for a number of two- and three-layered cylinders and, to demonstrate the versatility of the approach, natural frequencies are given for a five-layered cantilevered beam with a central circular hole as well as for a number of composite solids of more general shape.     

飞行器上设备软件在线升级方案设计与应用

为解决飞行器上各个设备软件升级困难问题,以飞行器上已有的通信接口为基础,设计了一套成本低、通用性好、可靠性高的飞行器上设备软件在线升级方案。试验结果表明,该方案简单可靠,可用于飞行器嵌入式设备软件的在线升级与维护,具有较好的应用前景。     

MJ系列数控车床的电气模块化设计方法

数控机床的模块化设计包括机械结构的模块化设计和电气控制系统的模块化设计两部分。文章以MJ系列数控车床为例，根据作者的实际工作经验，从电气控制的角度介绍了数控机床电气模块化设计的基本思路，提出了以PLC程序的模块化设计为核心的数控机床的电气模块化设计方法。     

支承辊拆装机液压系统的设计

为提高支承辊拆装作业效率,缩短拆装作业时间,降低工人的劳动强度;避免轴承等设备损坏,消除作业中的安全隐患,设计了一套板带热连轧厂支承辊拆装专用设备。     

浅析汽车零部件检验规程编制

针对汽车零部件检验规程的编制,提出不仅要依据相应零部件图纸和质量体系的有关规定进行科学性编制,更重要的是要依据检验环境进行实用性的编制,使其成为汽车零部件检验人员可操作的工作指导书。     

Features of Eddy-Current Tests of Spherical Components

The paper presents formulas convenient for computer calculations and solutions of electromagnetic problems related to tests of spherical objects made from either magnetic or nonmagnetic materials. Hodographs of relative induced signals for applied and pass-through eddy-current transducers, and the pulsed signal for dynamic tests of balls have been calculated.     

Application of Monte Carlo simulation for estimation of uncertainty of four-point roundness measurements of rolls

Large-scale rotors in the paper and steel industry are called rolls. Rolls are reground at regular intervals and roundness measurements are made throughout the machining process. Measurement systems for roundness and diameter variation of large rolls (diameter <2000 mm) are available on the market, and generally use two to four sensors and a roundness measurement algorithm. These methods are intended to separate roundness of the rotor from its movement. The hybrid four-point method has improved accuracy, even for harmonic component amplitudes. For reliable measurement results, every measurement should be traceable with an estimation of measurement uncertainty. In this paper, the Monte-Carlo method is used for uncertainty evaluation of the harmonic components of the measured roundness profile under typical industrial conditions. According to the evaluation, the standard uncertainties for the harmonic amplitudes with the hybrid method are below 0.5 μm for the even harmonics and from 1.5 μm to 2.5 μm for the odd harmonics, when the standard uncertainty for the four probes is 0.3 μm each. The standard uncertainty for roundness deviation is 3.3 μm.     

Calculation of absolute values of the spectral energy density of polychromatic radiation

A method for calculating absolute values of the spectral distribution of the radiant energy of a polychromatic source is described for the case in which the spectral distribution of the radiant energy is recorded in relative units, and the time dependence of a current pulse of a photodetector the spectral sensitivity of which is known in absolute units is measured. The expression for the time-averaged spectral density of the radiation power for the pulse-periodic operation of a radiant source is given.     

Inclusion of risk in evaluation of advanced technologies

Traditional economic evaluation techniques are often used to rank the technology alternatives for adoption purposes. However, the results of such evaluations are somewhat misleading since these techniques ignore the intangibles. Intangibles are factors that cannot be quantified for inclusions in the economic evaluation techniques but have great impact on the evaluation and adoption process. The current research addresses this issue by first identifying the intangible costs or risks of adopting a new technology and then developing a mechanism for their inclusion in the evaluation process. Taguchi loss functions are used as a tool for quantifying the intangible costs. The loss functions are developed based on the risks’ specification limits set by the decision maker. These loss functions are used to calculate a loss score for each technology candidate. The technology alternatives are then ranked based on their loss scores, and the technology with the lowest loss score is selected for adoption. The proposed methodology offers a powerful tool for evaluation of alternative technologies by complementing the traditional economic evaluation techniques.     

A method for improving the accuracy of evaluating the dimensions of flaws in walls of tubular elements of structures

An algorithm for evaluating the real accuracy of the basic measuring instrument (exterior or in-tube flaw detector) in measuring parameters of flaws of a particular inspected tube was proposed on condition that the basic measuring equipment has no systematic error, while a verification instrument is considered as “absolutely” precise or “reference.” A statistical method of increasing the accuracy of evaluating the dimensions of flaws in thin-walled tube elements was developed on the basis of a correlation between the dimensions of flaw parameters. It can be taken as a basis for finding real values of parameters of flaws and for performing reliable calculations of the residual strength and residual life, for scheduling optimal periods for the next inspection of pipelines, and for ranging segments of a pipeline by a risk criterion, thus providing optimal scheduling of repairs.     

Relation between the amplitude of acoustic emission of an ensemble of microflaws and the deformation rate: Reconstruction of the number of AE events during a change in the dynamic range of detected signals

A model of acoustic emission from a dislocation cluster during its passage through a boundary is considered. A dependence of the amplitude of an acoustic-emission (AE) event on the deformation rate and the loading frequency has been obtained. Algorithms for reconstructing the number of lost AE events below the discrimination threshold of the instrumentation are obtained for the case of a power-law amplitude distribution. A method for correcting the parameters of the detected stream of events at various discrimination thresholds, deformation rates, and loading frequencies is described. A method for estimating the dynamic range on the basis of the average value of the detected AE-signal amplitudes is proposed. We propose using the results of this study for increasing the reliability of the AE method for diagnostics of a prebreakdown state.     

飞行汽车双横臂悬架自由度计算分析

传统空间机构自由度计算多而且复杂,对于具体的计算有很多限制,不适合用来研究空间机构的运动。以飞行汽车悬架为研究对象,对空间自由度计算公式进行了分析,为悬架空间设计计算提供了依据。