Buckling and vibration of anisotropic or isotropic plate assemblies under combined loadings

This paper describes the underlying theory, and a general-purpose computer program, VIPASA, for determining the critical buckling stresses or natural frequencies of vibration of thin prismatic structures, consisting of a series of plates rigidly connected together along longitudinal edges. Each plate may be either isotropic or anisotropic and may carry a basic stress system consisting of longitudinal and transverse direct stress combined with shear. The structure is assumed to be subjected to a “dead load” system which does not cause buckling; in addition a “live load” system, defined in magnitude by a single load factor, may be applied and the value of the load factor at buckling is determined. Alternatively the natural frequencies of vibration of the structure when subjected to the dead load system are determined. Any number of critical load factors or natural frequencies can be obtained. The theory is based upon the assumption that all modes are sinusoidal, in the sense that all three components of displacement vary sinusoidally along any longitudinal line, but phase differences are incorporated to allow for the effects of anisotropy and shear. Apart from this assumption no further approximations are made other than those inherent in thin plate theory.     

托辊阻力系数的微机测试系统及其数据处理

阐述托辊阻力系数测试仪的测量原理,给出该仪器的结构原理图,设计计算机辅助测试系统及其阻力系统测试数据处理软件的结构,并给出测试数据处理主模块流程图。     

Development of a numerical methodology for analysis and design of weldments

There are many analysis formulas for determining the resultant shear force in welds. However, there is no general procedure which is applicable to a joint with all six possible loadings exerted simultaneously. A numerical methodology and computer program for such a problem were developed, and they are capable of analyzing a weld of any shape composed of straight or circular line segments. The computer program developed in this study can also display the design procedures and results using computer graphics. The development of such a design procedure and an interactive computer program for weldments analysis will lead to lower cost.     

Simulation of chevron crack formation and evolution in drawing

The objective of the present work is to clarify ductile fracture phenomena in bulk metal forming, by means of finite-element analyses and experiments. We have developed a computer program, based on a conventional computer program of the finite-element method, by which the behavior of crack propagation after ductile fracture can be analyzed. The phenomenon that inner fracture defects occur periodically in the axial direction in drawing has been simulated using the computer program. The following results were obtained. First, to analyze multipass drawing we have proposed a method of calculating residual stress after drawing and a method of considering initial stress before drawing. Second, to perform accurate simulation, we have developed a method of fracturing one element in each step and a method of separating nodes at the fracture. Finally, we have proposed a method for evaluating ductile fracture in terms of void volume fraction and axial stress, and we have shown the validity of the method by comparing the analytical results with experimental ones.     

Efficient multi-level substructuring with constraints for buckling and vibration analysis of prismatic plate assemblies

The use of substructuring in the buckling and vibration analysis of large structures permits very substantial improvements in computational efficiency. The exact multi-level substructuring capability of the widely used computer program VICONOPT for the analysis and optimum design of prismatic plate assemblies has been extended by the inclusion of new theory, presented in this paper, which permits constraints on any of the internal or external nodes of substructures. The computational savings by using substructuring in this way are shown to be typically 50–70% compared with previous VICONOPT solutions. The theory is applicable to any method or computer code for structures whose buckling or vibration modes combine responses of different half-wavelengths, with VICONOPT being used as an example.     

模块化系列化产品(减速器)的计算机辅助管理

本文介绍了模块化系列化产品(减速器)的计算机辅助管理软件的设计方法.包括系统的模块编码方法和管理程序的结构.     

洗衣机振动过程的计算机模拟研究

采用计算机模拟方法,以洗衣机工作过程的振动为例,研究了弹性固定机构的振动规律,提出利用动力学有限元技术研究振动的方法－－实时仿真分析技术（real time simulation RTS）。本文模拟洗衣机的振动过程,是有限元技术首次应用于非线性系统振动过程实时仿真的分析。该方法以机械结构的整体模型为分析对象,对结构的振动原因与振动形式综合考虑,获得的分析数据接近系统的实际运行状态,利用模拟分析可以研究激励、结构等因素对振动过程的影响,研究表明该方法是一种有效的辅助设计方法。     

液压支架多机控制系统通信结构分析探讨

根据液压支架在综采工作面中实际存在的互控、协调动作的要求,研究设计了以单片机为核心的分布式多计算机控制系统,分析了几种常见的多机通信结构及每种结构的性能特点,重点介绍了CAN多上位机通信总线控制系统的原理、结构、功能和控制方法．并通过联机实验证明了上位机和下位机之间、下位机和下位机之间的可靠的通信及互控功能。     

A general method for analysis of planar mechanisms using a modular approach

A method that covers both kinematic, inverse dynamic, dynamic, and static analysis of any type of planar mechanism is presented. The method is based on a subdivision of the mechanism to be analyzed into kinematic chains that are categorized as either neutral or expansion modules. The neutral modules are the well known Assur Groups, characterized by the fact that they have no effect on the degree of freedom of the mechanism. On the contrary each expansion module increases the degree of freedom by one. The coordinates that correspond to the indeterminancy of the expansion modules may be identified as a set of independent coordinates for the subdivided mechanism and used in any type of analysis. The method as it is described in the present paper has been implemented in a menu-controlled PC computer program CADME. A number of practical observations concerning the implementation of a modular approach is made and discussed.     

计算汽轮机动态特性的通用程序

本文介绍了在DJS-14机上计算汽轮机动态特性的通用程序及其使用方法。动态特性是衡量汽轮机组工作好坏的重要指标之一。在机组的设计、运行、调试时都要求进行动态分析或动态试验以保证机组有良好的动态性能。但要较精确而全面地计算动态特性各项指标,不仅很费时,甚至有时很困难,特别是当系统的数学模型阶数很高时更是如此。利用本程序可较方便地介决此问题,而且还可以进行大量的方案比较。使用时只需根据本文的规定,将系统的数学模型和相应的系数送入程序即可,程序本身不必作任何变动。     

TMS与计算机通信

分析了TMS与计算机通信的两种方式,根据其特点设计了适合TMS与计算机通信的电路与软件。经调试、仿真,证明其设计是合理的。     

FERImage: an interactive program for fractal dimension, d(per) and d(min) calculation

A computer program has been written for the determination of the D fractal dimension at low scale, of the d(per) representative parameter of the periodical region at high scale, and the d(min), representative parameter of the minimum elemental cell which is repeated in the periodical structure from the variogram. It carries out the simultaneous obtention of the three previous parameters developed by Bonetto and Ladaga. The program also allows to obtain fractal dimension values from the Fourier power spectrum. FERImage has been developed so that the users could choose the rank where the behavior is fractal, not only in the variogram method but also in the Fourier spectrum method.     

三相异步电动机测试分析系统设计

针对电机测试中存在的问题,利用西门子PLC和C#设计了一套三相异步电动机测试分析系统。介绍了系统的试验流程和上/下位机设计方案,采用工业以太网和RS-485网络相结合的方式实现了上/下位机的通信,并给出了网络结构及参数设置。给出了系统需采集的电压、电流等参数的硬件设备和配置;采用C#高级语言开发了上位机测试和分析程序,并用最小二乘法实现了电机测试曲线的拟合。投运结果表明,系统达到了规定的设计性能指标和要求,提高了工作效率。     

蒸发器支座结构分析

通过多个模型的建模及有限元分析支座的受力情况，总结出蒸发器的支座形式，为大型容器支座设计提供相应的参考。     

PLC-单片机-点阵液晶显示器双总线监控系统的研究

本文基于计算机三总线的组成和时序配合的基本原理，提出了可靠程序控制器（PLC）输出信息的总线结构，应用82C55可编程接口芯片作为桥梁，将PLC输出总线与单片机总线结合，组成一种全新的控制系统。论述了其总线与单片机总线时序配合的工作原理，PLC的地址，数据结构与程序设计方法，介绍了PLC－单片机－点阵式液晶显示器监控系统电路组成的基本原则和总线时序配合的编程方法，点阵式液晶显示器汉字和字符显示编程方法，讨论了系统的可靠性，抗干扰性，PLC总线配置的灵活性等问题。     

Stochastic error analysis in cam mechanisms

A probabilistic method is outlined for obtaining the variances in displacement, velocity and acceleration of followers in cam mechanisms for any given manufacturing tolerance on the cam profile. A follower motion equation is obtained by expansion in a Taylor series and considered in both linear and second-order terms. The equation is analyzed with random variables for the kinematic displacement, velocity and acceleration of the follower employing stochiastic techniques including finite differences and the maximum likelihood method. A general computer program allows the designer to obtain projected output errors for any commonly used disc cam type, and an example of one of these is included.     

An upper bound method for analysis of three-dimensional deformation in the flat rolling of bars

A new upper bound method for the analysis of three-dimensional deformation in the flat rolling of bars is proposed. In the conventional upper bound method, stress distribution is not calculated. Hence, a new method of calculating stress distribution is proposed in which the hydrostatic stress in each element and the contact stress on the contact surface between material and roll in each element are calculated. In the conventional upper bound method, the structure of the computer program also depends highly on the kinematically admissible velocity fields assumed. Hence, a new method of analysis in which the structure of the computer program depends minimally on the kinematically admissible velocity fields assumed is proposed. In the analysis of strip rolling, the calculated roll force and roll torque agree with the roll force and roll torque calculated from Sims’ slab method. In the analysis of the flat rolling of bars, the calculated width spread agrees with the width spread obtained by experiments reported in the literature. The effects of a reduction in thickness, roll radius, material width-to-height ratio, front tension, back tension, and front and back tensions on the width spread, forward slip, roll force and roll torque are demonstrated. Hence, the validity of the new upper bound method is confirmed.     

ZLG7290扩展键盘在ARM Linux系统中的应用

针对人机界面按键需求多、资源要求少,模块化,方便移植等问题,提出了将一款支持I2C总线数据格式、提供键盘中断信号的键盘扫描管理芯片ZLG7290应用于ARM Linux系统中.按键通过I2C总线主机通信的方式,克服了传统方法的不足,节约了硬件资源.研究结果表明,该方案便捷、灵活地解决了上述矛盾,稳定、可靠,具有实际应用...     

HITECH触摸屏与单片机的通信协议

触摸屏通常可以直接对PLC的变量进行读写编程,但对于单片机用户,触摸屏提供自定义通信协议,需要根据不同单片机进行编程,实现数据交换。针对此问题,对Hitcech触摸屏自定义通信协议进行了研究,基于单片机PIC18F452介绍了HITECH触摸屏与单片机实现串行通信的方法,给出了硬件电路连接图、通信协议以及关键通信程序。