The prediction of creep rupture of pressurized tubes using a model for void growth and coalescence

A phenomenological formulation based on a theory of plasticity for voided solids, and power-law creep, to estimate the rupture times and strains for pressurized tubes is presented. Realistic values of the damage parameters involved are selected by satisfying the creep rupture uniaxial data for the same materials. Void growth and coalescence and hence the loss of load-carrying capacity of the tube is taken as a failure criterion. Computed values of rupture times for thin- and thick-walled tubes are shown to be mostly in close agreement with the experimental data found in the literature. Only fair agreement among predicted and experimental fracture strains is observed.     

泛灰数学在机构误差分析中的应用

在概述泛灰数的概念及其运算规则的基础上，介绍了泛灰数与区间数的转化，利用泛灰数的可扩展性对区间进行分析，研究了泛灰线性方程求解，然后将它应用于机构误差分析中，泛灰数不仅具有区间分析的功能，而且能解决区间分析所不能解决的问题。它为机构误差分析提供了新的方法。最后给出了算例作了对比分析。     

套筒与轴热套装过程的接触有限元分析

运用MSC.Marc对套筒与轴的热套装过程进行有限元模拟,涉及热机耦合分析和接触分析。在建立合理的有限元模型、正确定义和选择边界条件的基础上,分析套筒受热自由膨胀状态以及套筒与轴过盈配合的应力应变,最后通过对比分析模拟结果与试验结果验证有限元分析的合理性,为结构的进一步改进提供理论依据。     

三坐标划线仪的回程误差分析与改进

基于汽车转向轮的力学原理,着重以力学分析方法分析三坐标划线仪的机械结构产生回程误差的原因,并提出了改进仪器运动部件的新结构,从而提高三坐标划线仪整体的精度。     

TI蜗杆传动齿面接触误差的计算与分析

采用CAD三维造型技术与数值计算相结合的方法计算分析了各种加工误差及装配误差对TI蜗杆传动齿面接触的影响。其结果对有效提高TI蜗杆副的制造精度有指导意义。     

星载超光谱成像仪摆镜系统轴系的误差分析与设计

摆镜系统轴系的精度会影响星载超光谱成像仪的成像质量。轴系设计时采用了向心推力球轴承来调整轴系的装配误差。分析了摆镜系统工作时影响轴系精度的几个误差源,包括零件的尺寸误差、同轴度误差、配合误差等,按照误差理论设计并计算了各误差值,得到轴系的径向晃动误差和角运动误差。对加工好的轴系进行精度检测,实验结果符合理论结果,验证了该摆镜系统的轴系结构设计的合理性和可靠性,为该类航天运动部件的轴系结构设计提供了参考依据。     

分布式监测系统应用服务器设计

在分析分布式实时监测系统结构及实时数据处理的基础上，提出一种通用实时监测应用服务器设计方案。本应用服务器采有多线程机制，在线采集工业控制的实时数据，通过浏览器可视化组件动态发布设备运转及生产状况信息。本方案具有完善的页面请求、客户请求、以及数据对象的管理和服务功能，其结构灵活，系统维护性强。     

Adaptive modelling of the milling process and application of a neural network for tool wear monitoring

An adaptive signal processing scheme that uses a low-order autoregressive time series model is introduced to model the cutting force data for tool wear monitoring during face milling. The modelling scheme is implemented using an RLS (recursive least square) method to update the model parameters adaptively at each sampling instant. Experiments indicate that AR model parameters are good features for monitoring tool wear, thus tool wear can be detected by monitoring the evolution of the AR parameters during the milling process. The capability of tool wear monitoring is demonstrated with the application of a neural network. As a result, the neural network classifier combined with the suggested adaptive signal processing scheme is shown to be quite suitable for in-process tool wear monitoring     

碱回收燃烧工段自动控制系统的设计及应用

介绍了碱回收燃烧工段的工艺流程,完成了黑液调节、送引风、锅炉供水、燃烧过程控制及连锁保护等子系统的设计及其软硬件实现,并将变频器运用于其中,既可以很细微地调节送、引风量,又有显著的节能效果,极大地降低了运行成本.     

The use of simulation modeling and factorial analysis as a method for process flow improvement

Over the past quarter century, much effort has been devoted to the design and development of simulation modeling languages, and to methods for the development of simulation models themselves. Less effort, however, has been expended on the design of the experimental models upon which simulation studies are based. This paper describes a methodology for the determination of near optimal solutions considering experimental design and simulation modeling. Using this methodology, simulation scenarios are created and analyzed using an analysis of variance (ANOVA)-based experimental design. This paper also presents an application of this method in analyzing a manufacturing system design problem.     

Error analysis and compensation for the volumetric errors of a vertical machining centre using a hemispherical helix ball bar test

Machining accuracy is directly influenced by the quasi-static errors of a machine tool. Since machine errors have a direct effect upon both the surface finish and geometric shape of the finished workpiece, it is imperative to measure the machine errors and to compensate for them. A laser measurement system to identify geometric errors of a machine tool has disadvantages, such as a high cost, a long calibration time and the usage of a volumetric error synthesis model. In this study, we proposed a novel analysis of the geometric errors of a machine tool using a ball bar test without using a complicated error synthesis model. Also, a statistical analysis method was employed to derive geometric errors using a hemispherical helix ball bar test. According to the experimental result, we observed that geometric errors of the vertical machining centre were compensated by 88%.     

分维数结合多分辨分析诊断压缩机轴的运行状况

针对透平压缩机异常运行时轴的振动情况,采用分维数结合双正交小波的多分 辨分析的方法,对轴的振动信号进行处理,为判别不同的故障类型,实现对轴的运行 状态的监测与故障诊断提供了一种可靠的途径。     

行星轮系在烟草机械中的应用与分析

通过对行星轮系在卷烟机中的应用与运动分析，得出吸爪的运动轨迹为椭圆，运动方式为平动；导出了吸爪中心轨迹的计算公式，用来确定吸爪工装上的孔位，可一次装配成功。     

Dynamic analysis of a rotating beam subjected to repeating axial and transverse forces for simulating a lathing process

The dynamics of the workpiece of a lathe is simulated in the presented paper. A rotating Rayleigh beam is chosen as a simple model of the workpiece. The beam or the workpiece is subjected to forces from the cutting tool of the lathe. The external forces, in transverse and axial directions, are traveling in a repeating or periodic motion. The force in the axial direction is a large cutting force resulting in coupled bending deformation while forces in the transverse directions are the contacting forces.In this paper, the governing equations of the rotating Rayleigh beam are derived by Hamilton's principle. The external, periodic forces resulted from the tool are expressed in Fourier series. Galerkin's method is then chosen for disceretizing the partial differential equations. The instability regions of the responses are determined by using the method of multiple scales and the Floquet theory. Fast Fourier transform gives the frequency domain responses for examining the dynamic characteristics. The numerical results are discussed. Parametric studies are also performed.     

The application of a radial basis function neural network for predicting the surface roughness in a turning process

This study considers the performance of a radial basis function neural network for predicting the surface roughness in a turning process. A simple algorithm is proposed for finding the upper and lower estimates of the surface roughness. A code is developed that automatically fits the best network architecture for a given training and testing dataset. The validation of the methodology is carried out for dry and wet turning of mild steel using HSS and carbide tools, and is compared to the performance of the studied network with the reported performance of a multi-layer perception neural network. It is observed that the performance of the radial basis function network is slightly inferior compared to multi-layer perceptron neural network. However, the training procedure is simpler and requires less computational time.     

往复式压缩机气阀运动规律测试系统中传感器的选择与应用

阐述在气阀运动规律测试系统的信号采集部分如何选择合理的传感器,对各种传感器进行详细的说明和对比,通过实验的比较,给出一种最佳的选择方案。     

印刷机高点闭牙机构运动分析方法及应用

针对印刷机高点闭牙机构在高速运行时所产生的冲击、噪声问题,结合机构的运动特征,提出印刷机高点闭牙机构运动分析的一般方法,建立机构分析方程;通过对xj4142型印刷机高点闭牙机构的运动分析,得到机构的运动特性.分析结果表明:高点闭牙机构的冲击、噪声问题的根源在于运动过程中绝对加速度的突变.     

多刚体系统运动学分析的自然坐标法及在悬架运动学分析中的应用

本文介绍了一种适用于计算机分析的多刚体系统运动学分析的自然坐标法。利用自然坐标描述多刚体系统时,只需要一些点和一些单位向量,刚体的约束方程和运动副的约束方程组成了多刚体系统的运动学约束方程。约束方程均为线性或二次方程,因此求解方便。文中利用该方法分析了Maepherson悬架的轮胎横向滑移量、主倾内倾角等与车轮上、下跳动距离的关系。     

基于微差原理的A/D转换方法分析与应用

介绍了一种基于微差原理的A/D转换方法，进行了理论分析，分析和应用表明，该方法非常适合于精确测取被测信号的微小变化量，能有效地避免测量结果有效位数的损失，即使在小信号输入或小变化量情况下，仍能取得满意的测量效果。     

氯甲烷连续回收过程计算机综合控制系统设计与应用

应用WebField JX-300XP系统设计亚磷酸二甲酯-草甘膦联产尾气-氯甲烷连续回收过程的计算机综合控制系统，并用SCX语言编程实现主要设备的控制与连锁保护。实际运行结果表明，该系统稳定可靠，控制精度高，满足生产工艺要求，经济效益明显。