DEVELOPMENT OF COMPUTER AIDED PROCESS PLANNING SUBSYSTEM FOR A CAD/CAPP INTEGRATED SYSTEM

Based on Group Technology, a CAD/CAPP integrated system is developed. This paper mainly covers the research work of the CAPP subsystem. In this subsystem, geometric and manufacturing information is obtained from the CAD data base, modular block programming and full Chinese menu are adopted, process planning is produced with the semi-generative method, and process card involved the operation charts is yielded by printer. The operation is simple and convenient, and the performance is quick. The ? CAPP subsystem is successfully integrated with the CAD subsystem. The subsystem is an advanced CAPP system.     

Study on CAD System of Slope Pile-Anchor Retaining Structure

The process of designing the common slope pile-anchor retaining structure in Chongqing is analyzed, the finite element method is applied to calculate the force of the structure and design the anchor bar, pile and holding sheet. The CAD system is developed including fore-process, post-process, calculation of the structure and drawing by computer in order to make the designing of slope pile-anchor retaining structure more quickly, more economical and convenient. It has been applied in practice of the slope engineering with a good result.     

3-D Reinforcing CAD System of Hydropower Station Dam Passageway

By researching passageway, the features of passageway reinforcing design and draw are analyzed, and the mathematics model of orthogonal passageway and slant passageway are established. The method of applying CATIA V5 to hydro-structure is explored and a scheme of 3-D visual reinforcing CAD System is designed. It is proved by practice that the system is not only convenient to input parameter, but also to use universally. The system can use in design and researching of orthogonal passageway and slant passageway. It is very quick and easy that revise reinforcing bar of reinforcing drawing in construction.     

氯氧镁水泥混凝土中钢筋的腐蚀与防护试验研究

结合氯氧镁水泥混凝土耐水性，研究氯氧镁水泥混凝土中钢筋的腐蚀与防护，试验变量包括钢筋种类、混凝土保护层厚度和腐蚀龄期等。钢筋种类包括裸露钢筋和美加力涂层钢筋；混凝土保护层厚度包括25、50 mm；腐蚀龄期包括60、120、180、240、300、360 d。试验采用自来水长期浸泡至试块2/3处，并采用扫描电子显微镜（SEM）和能谱仪（EDS）对腐蚀后的钢筋微观结构和化学元素组成进行分析，研究钢筋的腐蚀机理。结果表明，通过软化系数分析，氯氧镁水泥混凝土的软化系数处于0.78～0.87，说明试验设计的氯氧镁水泥混凝土可用于干燥地区、受潮较轻地区或次要建筑结构。通过极化曲线及其电化学参数分析，裸露钢筋腐蚀速率为美加力涂层钢筋腐蚀速率的40～80倍，说明涂层防腐效果明显。     

Study on Pre- & Post- Processing Program for Multi -storey & Tall Steel Frame

A vast amount of information data must be input before finite element analysis of steel frames, such as node information, element information and load information. It is necessary to develop a computer aided design system with 3D interactive function. A CAD system for steel frame based on object ARX is developed with AutoCAD API and the Object -oriented technique. In this paper, some key programming technologies is studied, including design of structures, identification of floor system, also, it has presented the relevant implementing code.     

A METHOD FOR THE ORIENTATION OF CHINESE CHARACTERS IN THE INTERFACE PROGRAMMING OF AUTO CAD DXF DOCUMENT

The orientation of Chinese characters is very importantin the interface programming design of Auto CAD DXF documents.Beca-use some parameters are automatically computed by the Auto CADsystem,it is very difficult for Chinese characters to be oriented in DXFinterface programmings.This paper reports the calculating method of ori-ented parameters and the orientation method of Chinese characters in theinterface programming of DXF documents,and gives a general Fortran 77subroutine for the orientation of Chinese characters.The method solves thedifficulty of the orientation of Chinese characters in the interface program-mings of DXF documents,and makes it convenient for various CAD pic-tures to be oriented in Chinese Characters.     

Discussion on Interactive Method for CAD Drawing andCalculation in Building Water Supply and Drainage Design

According to the features of CAD for building water supply and drainage design,the interactive method for CAD calculation and drawing in building water supply and drainage engineering are discussed . A practical example of ADS for hydraulic calculation has been given in this paper .     

Experimental Research on High-strength Inorganic Anchoring Material

A new type of inorganic anchoring material is developed as a substitution for anchoring adhesive to overcome some imperfections in the process of planting reinforcing steel bar.The mix proportion of the anchoring material is determined by experiments.The compressive strength,adhesive force to concrete,volume stability and anchoring force with steel bar are studied.The early strength of the anchoring inorganic material is quite high: for 1d up to 38.5MPa and 3d up to 60MPa.It is a good adhesive to concrete and the adhesive strength of 28d is about 2MPa.The anchoring material will have tiny volume expansion with the age,which is beneficial to enhancing the anchoring force.The essential component of the inorganic anchoring material is cement-based material,so some defects of the organic macromolecular material can be avoided,such as poor stability and requirement for vigorous construction conditions.Its characteristics in early strength,adhesive force to concrete and volume expansion can satisfy the requirement of the construction to the planting reinforcing steel bar and the loading force,thus it can be used as a substituting material for anchoring adhesive.     

SERIES-PARALLEL CORRECTION AND CAA FOR CANONICAL SYSTEM TYPE 2

This paper presents a simple and efficient engineering design method of series-parallel correction for canonical system type 2 and gives a practical design example.The following and anti-disturbance performances of the system by means of digital simulation are analyzed.The performance indexes in different design parameters are listed.This paper is available for reference in engineerng design.     

A COMPUTER METHOD FOR COMPARISON BETWEEN EHVAC AND EHVDC TRANSMISSIONS

A computer method for comprehensive comparison between EHVAC and EHVDC is presented in this paper after analyzing the fundamental characteristics and studying the design methods of these two types of transmi-sson schemes. Some formulas are developed and an appropriate mathematical model is established. A generally applicable computer program is exploited which is acceptable to IBM-pc and its compatible micro-computers. The results of numerical practical project of the program are given to prove the correctness of the model and the program described in this paper,and it also shows that the method proposed is an efficient one with the practical values in power system planning.     

A SENSITIVITY METHOD FOR THE WEIGHTING MATRIX SELECTION OF LINEAR OPTIMAL CONTROL

The paper analyses the relations between closed-loop system dynamic qualities and linear optimal control weighting matrix Q and offers a sensitivity method for selecting weighting matrix Q. As a practical example, a linear optimal supplement excitation control system is designed for a single machine-infinite bus power system using the presented method. Theoretical . analysis and simulation results have shown that the dynamic qulities of the control system are very satisfactory.     

THE DECENTRALIZED LOAD FREGUENCY CONTROL FOR MULTI-AREA POWER SYSTEMS

A decoupled load-frequency control model of a multi-area interconnecting power system is presented and a practical and effective decentralized control method is developed, which needs only its own state information and the information measured in it. It can also improve the stability and dynamic characters of the system. The dynamic simulation of the numerical example of a three-area interconnecting system with this controller showes the dynamic characters are almost the same as the centralized full state feedback optimal control.     

PROTOTYPE: A NEW MIXED PATTERN FOR KNOWLEDGE REPRESENTATION

In this paper, it is pointed out that some kind of mixed pattern for knowledge representation should be needed in CAD systems, and prototype is just one of this kind of pattern, which is most suitable to representing the relative design knowledge.The paper particularly elaborates the notion of prototype and introduces how to represent a design prototype.Operations on prototypes are also demonstrated in order to conceive the reasoning mechanism in a prototype-based design system.     

The Finite Element Method for Frame Structure with Fuzzy Elastic Connections

The connections of frame structure elements at a node are ofen an elastic connection between hinged and rigid.In this paper,the stiffness matrix and the loading transfer matrix of frame element with turn elastic connections is deduced,the cross shear effect has been taken into consideration simultaneously.The stiffness matrices of some bar elements,such as both ends of the bar are hinged or rigid and one end is hinged but the other is rigid,are special cases of the stiffness matrices presented in this paper.After pointing out that the elastic coefficient at a node of a bar element with elastic joint is really a fuzzy quantity,the fuzzy stiffness matrix of the bar element is obtained,and a solution to structural fuzzy finite element equilibrium equations is presented.The fuzzy solution obtained from above is not only containing the solution of ordinary finite element method but also providing some additional informations with practical value.[WT5HZ]     

Theoretical Contour Line of Reinforcement Bar of Non uniform Corrosion

Most of the previous studies on corrosion of the steel bar in reinforced concrete structures is based on the assumption that the bar is uniformly corroded. The actual measurement in projects proved that most of the reinforcement bar is in non uniform corrosion state. Based on electrochemical principles of metal corrosion and combined with the real corrosion course of the bar in concrete structures, a theoretical model of the contour line of reinforcement bar due to non uniform corrosion is established, through deducing the speed of corrosion and theoretical corrosion penetration and volume changes due to corrosion of reinforcement in general air at different position and different time. At the same time, the model is verified with the results from relative references and measured data.     

Breaking incompatibility of Brassica oleracea L. by steel-brush pollination

Summary A method is described of breaking self-incompatibility in Brussels sprouts by mutilating the stigmata during pollination with a brush of which the hair had been replaced by steel wire. The results are similar to those obtained with bud pollination and the method opens up prospects for practical use.     

Analysis of Flexural Failure Mode of RC Beams Reinforced with Prestressed FRP Bars

The flexural performance of the beams reinforced with both non-prestressed bars and prestressed bonded FRP bars was theoretically analyzed. Both the CFRP bar and the AFRP bar were taken as the representatives in the study. Correlativity of two kinds of balanced relative depth of compressive area, respectively corresponding to the yield of steel bar and to the rupture of FRP bar, was investigated. Therefore the influence of performance parameters of FRP on the flexural failure modes was analyzed. The results indicate that failure modes and two kinds of balanced relative depth of compressive area are with direct correlation, and the latter is directly influenced by the performance of the FRP bars. Adopting the short-term performance parameters or the long-term performance parameters, which considers the environmental factor, creep fracture factor, relaxation factor and materials coefficiency, would have different results. Failure mode I is the ideal one, while the others should be avoided. Prestressed control stress of CFRP bars with low-ductility should not be too high, otherwise the rupture of CFRP bars will happen before the yield of steel bars.     

THE OVERLAPPING DECOMPOSITION DECENTRALIZED CONTRAL FOR GENERATOR''S EXCITER/GOVERNOR SYSTEMS

In this paper the generator's exciter/governor system are decomposed by using the overlapping decomposition method, and an overlapping decomposition decentralized control (ODDC) system is designed for the exciter /governor systems. In or.dar to enhance the dynamic qualities of the decentralized control system, the concept of the second feedback system is introduced to modify the first feedback gain matrix on the condition of the structure of the original decentralized control system maintaining unchanged. The practical decentralized control system design and its; simulation results show that this method greatly improves the control effect of the ODDC system and also holds all the advantages of the ODDC system. Besides, this paper indicates that it is a simple and effective method to control excitor/governor system by overlapping decomposition decentralized control strategy.     

冻融环境下钢筋与粉煤灰混凝土的粘结性能

通过对内贴应变片钢筋的直接拔出试验,分析冻融作用下粉煤灰掺量对钢筋与粉煤灰混凝土间粘结性能的影响,得出冻融循环作用对钢筋与粉煤灰混凝土之间粘结性能的影响规律。试验结果表明：钢筋与粉煤灰混凝土的粘结强度随粉煤灰掺量的增加而降低;当粉煤灰掺量一定时,随着冻融循环次数的增加,混凝土强度有所下降,钢筋与粉煤灰混凝土间极限粘结强度降低;当粉煤灰掺量较大,达到40%时,随冻融次数的增加,钢筋粉煤灰混凝土试件极限粘结强度的下降幅度明显减缓,极限粘结强度对应的滑移量增大。表明掺入较多粉煤灰可使试件的冻融损伤现象得到缓解,冻融环境下钢筋混凝土的粘结性能得到提高。     

About the Synthesis Method of Planar Multilink Mechanisms Based on Genetic Algorithm

This paper discusses the method of synthesizing planar multilink mechanisms based on GA. The pivotal technology is coding, creating population, account fitness, genetic operation and defining population size. This method does not require initial mechanisms and can search for plural appropriate mechanisms simultaneously. It is efficient about the non-linear problem. As an example, configuration of 4-bar planar mechanisms is decided in a practical application. It can be used the synthesis of 6-bar or more bar planar mechanisms as well.