Bond-slip constitutive relationship between bars and mortar for block masonry

Ten specimens were tested in this paper in order to study the bond behavior and the process of force transfer when bars adhered to mortar. The development of the bond stress between bars and mortar was calculated. Test results show that the maximum bond-stress is not influenced by the bar bond length and increases as the increased splitting strength of mortar for block. The local bond stress-slip curve was obtained. Then,based on the regressive analysis of test data,two bond shearing stress-slip constitutive models between bars and mortar were proposed. The models can be used in the numerical simulation or finite element analysis and provide references for the improvement of the corresponding design codes.     

Slab Tracking and Controlling on Hot Plate Rolling Line

By studying the slab moving in detail in the plate rolling process, the problem of slab tracking and controlling was solved by using the distributed control system. The problems of rhythm control for the big-complex system, the exchange of manual and automatic operations, the data exchange between the levelⅠ, TCS (technology control system) and levelⅡ, PCS (process control system), are solved. By this way, the automatic level of the plate production line is improved.     

Product Knowledge Representation and Integration Technology in Web-based Collaborative Design

1 Introduction 1 .1 Product KnowledgeProduct knowledge , which consists of a characteristic set and correlative constraint and rule sets ,can beusedtocontrol andi mprovethe quality of product informationchange[1 ,2].Fig.1 showsthe relationship betweenproduct information and knowledge .Product information,such as BOM(Bill of Material) and CAD(ComputerAided Design) models ,is the basic data for product manufacturing while product knowledge describes the con-straints of product information. …     

Modeling and finite element analysis of rod and wire steel rolling process

Two thermomechanical coupled elastic-plastic finite element （FE） models were developed for predicting the 12-pass continuous rolling process of GCrl 5 rod and wire steel. The distances between stands in the proposed models were set according to the actual values, and the billets were shortened in the models to reduce the calculation time. To keep the continuity of simulation, a technique was developed to transfer temperature data between the meshes of different models in terms of nodal parameters by interpolation functions. The different process variables related to the rolling process, such as temperature, total equivalent plastic strain, equivalent plastic strain rate, and contact friction force, were analyzed. Also, the proposed models were applied to analyze the reason for the occurrence of an excessive spread in width. Meanwhile, it was also utilized to assess the influence of the roll diameter change on the simulated results such as temperature and rolling force. The simulated results of temperature are found to agree well with the measured results.     

Oil production rate predictions for steam assisted gravity drainage based on high-pressure experiments

Dual-well steam assisted gravity drainage(SAGD) has significant potential for extra-heavy oil recovery.China is conducting two dual-well SAGD pilot projects in the Fengcheng extra-heavy oil reservoir.Quick,direct predictions of the oil production rate by algebraic models rather than complex numerical models are of great importance for designing and adjusting the SAGD operations.A low-pressure scaled physical simulation was previously used to develop two separate theoretical models corresponding to the two different growth stages observed in the SAGD steam chambers,which are the steam chamber rising stage and the steam chamber spreading stage.A high-pressure scaled model experiment is presented here for one dual-well SAGD pattern to further improve the prediction models to reasonably predict oil production rates for full production.Parameters that significantly affect the oil recovery during SAGD were scaled for the model size based on the reservoir characteristics of the Fengcheng reservoir in China.Experimental results show the relationship between the evolution of the steam chamber and the oil production rate during the entire production stage.High-pressure scaled model test was used to improve the gravity drainage models by modifying empirical factors for the rising model and the depletion model.A new division of the SAGD production regime was developed based on the relationship between the oil production rate and the evolution of steam chamber.A method was developed to couple the rising and depletion models to predict oil production rates during the SAGD production,especially during the transition period.The method was validated with experiment data and field data from the literature.The model was then used to predict the oil production rate in the Fengcheng reservoir in China and the Athabasca reservoir in Canada.     

Thermodynamic study of K2CrO4-KAlO2-KOH-H2O and NaeCrO4-NaALO2-NaOH-H2O systems

Phase diagrams of complex multi-component aqueous chromium salt system are the important theoretical bases for increasing the recovery ratio of chromium and reducing the poisonous waste in the chromate production process. Phase equilibrium of multi-component system has been calculated from the limited known data with thermodynamic models. The phase equilibriums of KOH-K2CrO4-H2O, KOH-KAlO2-H2O, NaOH-Na2CrO4-H2O and NaOH-NaAlO2-H2O systems were calculated with thermodynamic models. The solubilities of Cr and Al was measured in the systems at different temperatures. The results were compared with experimental data and they are consistent with each other. It shows that the lower concentration of KOH (or NaOH) is favorable for thecrystallization of KAlO2 (or NaAlO2) and higher concentration of KOH (or NaOH) is favorable for the crystallization of K2CrO4(Na2CrO4). Therefore, K2CrO4 (or Na2CrO4) can be separated from KAlO2 (or NaAlO2) with controlling the KOH concentration in solutions of KOH-K2CrO4-KAlO2-H2O or NaOH-Na2CrO4-NaAlO2-H2O systems.     

Construction method of Chinese sentential semantic structure

A new method is proposed for constructing the Chinese sentential semantic structure in this paper.The method adopts the features including predicates,relations between predicates and basic arguments,relations between words,and case types to train the models of CRF + + and dependency parser. On the basis of the data set in Beijing Forest Studio-Chinese Tagged Corpus( BFS-CTC),the proposed method obtains precision value of 73. 63% in open test. This result shows that the formalized computer processing can construct the sentential semantic structure absolutely. The features of predicates,topic and comment extracted with the method can be applied in Chinese information processing directly for promoting the development of Chinese semantic analysis.The method makes the analysis of sentential semantic analysis based on large scale of data possible. It is a tool for expanding the corpus and has certain theoretical research and practical application value.     

Relationship between speed and traffic accident and speed limit on freeway

To develop an equation between discrete degree of speed and traffic accident on freeway in China and give reasonable suggestions of speed management, the relation model was established between speed standard deviation and accident rate per 100,000,000 vehicle kilometers by regression analysis. The model shows that the more discrete is the speed distribution, the higher is the accident rate, which provides theoretical gist for speed limit on freeway. It is suggested that speed limit should be set according to 85th percentile speed obtained by the relationship between 85th percentile speed and RCCs （curvature change rate of single circular curve）, and different speed limits should be set for cars and trucks. Through analyzing spot speed data of eight freeways in China, regression models were established between 85th percentile speed and RCCs and 15th percentile speed and RCCs Reasonable speed limit suggestion values are put forward through these models.     

Utilizing partial least square and support vector machine for TBM penetration rate prediction in hard rock conditions

Rate of penetration(ROP) of a tunnel boring machine(TBM) in a rock environment is generally a key parameter for the successful accomplishment of a tunneling project. The objectives of this work are to compare the accuracy of prediction models employing partial least squares(PLS) regression and support vector machine(SVM) regression technique for modeling the penetration rate of TBM. To develop the proposed models, the database that is composed of intact rock properties including uniaxial compressive strength(UCS), Brazilian tensile strength(BTS), and peak slope index(PSI), and also rock mass properties including distance between planes of weakness(DPW) and the alpha angle(α) are input as dependent variables and the measured ROP is chosen as an independent variable. Two hundred sets of data are collected from Queens Water Tunnel and Karaj-Tehran water transfer tunnel TBM project. The accuracy of the prediction models is measured by the coefficient of determination(R2) and root mean squares error(RMSE) between predicted and observed yield employing 10-fold cross-validation schemes. The R2 and RMSE of prediction are 0.8183 and 0.1807 for SVMR method, and 0.9999 and 0.0011 for PLS method, respectively. Comparison between the values of statistical parameters reveals the superiority of the PLSR model over SVMR one.     

Thermodynamic study of K_2CrO_4-KAlO_2-KOH-H_2O and Na_2CrO_4-NaAlO_2-NaOH-H_2O systems

Phase diagrams of complex multi-component aqueous chromium salt system are the important theoretical bases for increasing the recovery ratio of chromium and reducing the poisonous waste in the chromate production process. Phase equilibrium of multi-component system has been calculated from the limited known data with thermodynamic models. The phase equilibriums of KOH-K2CrO4-H2O, KOH-KAlO2-H2O, NaOH-Na2CrO4-H2O and NaOH-NaAlO2-H2O systems were calculated with thermodynamic models. The solubilities of Cr and Al was measured in the systems at different temperatures. The results were compared with experimental data and they are consistent with each other. It shows that the lower concentration of KOH (or NaOH) is favorable for the crystallization of KAlO2 (or NaAlO2) and higher concentration of KOH (or NaOH) is favorable for the crystallization of K2CrO4 (Na2CrO4). Therefore, K2CrO4 (or Na2CrO4) can be separated from KAlO2 (or NaAlO2) with controlling the KOH concentration in solutions of KOH-K2CrO4-KAlO2-H2     

基于CMM反求工程中的数据转换

反求工程表现为对原型的参照设计，在只有实体而没有工程图纸的情况下，利用三维数据获取设备取得实体的三维数据，然后利用三维重构软件生成实体的几何模型，最后在此基础上生成数控加工程序控制数控机床或应用快速原型机加工出样件.三坐标测量机(CMM)是反求工程的一种重要数据获取设备，针对我国许多企业中的CMM未更新换代，不能以标准的IGES格式输出数据，为此提出了一种中间数据格式，可以实现多种CMM与多个CAD/CAM系统的数据转换，并可以实现数据的自动分色分层.     

数据交换标准在CMM/CAD系统中的应用研究

为了解决逆向工程中三坐标测量机测量数据与CAD/CAM系统之间的数据交换问题,研究了VDA-FS文件并设计了基于VDA-FS文件格式的数据转换模块,利用Quindos测量语言编制数据转换文件程序,实现了将测量机的点位数据转换为标准的VDA-FS格式文件。经过测试,几何数据转换完整,结果可靠。     

基于PLIB的开放式零件库系统的开发与研究

通过对ISO 13584(零件库)标准及其发展应用趋势的研究，自定义所需的标准接口函数集，扩充并完善PUB31标准；另一方面采用STEP应用协议来实现零件库信息的表达与交换，增加了一种新的零件库的实现方式；提出了一种基于网络的开放式零件库系统的总体开发模式，并讨论了此库的构造、零件信息编码、几何编程接口、标准数据访问接口SDAI的函数联编和零件库的几种信息交换的实现方法，在此基础上为零件库提供了库开发工具。     

An Inspection Information Integration System of CAD and CMM

Manual definition of inspection feature in Coordinate Measuring Machines (CMM) is time-consuming and error- potential.Since CAD model contains all design data,an integration system of CAD/CMM is constructed to automate above pro- cess.First,tolerance feature and its attributes,including tolerance type,value and tag of related geometry,are extracted from CAD model and written to QDAS file,based on feature technology.The tags are then added as attribute to related geometry in CAD model.Thereby they can be automatically remarked in the parameter list of their corresponding geometric item when exporting STEP file.At last,both STEP and QDAS file are imported to CMM system.Based on the mapping between geometric and toler- ance feature in neutral files,inspection features can be recognized by CMM without manual interruption.The system has been im- plemented on Unigraphics platform,and proved to applicable for all types of tolerance and geometry.     

曲面造型的几何体素构造法

在ＣＡＤ，ＣＡＭ系统中，怎样更好地构造出有效的物体几何模型是系统的关键问题．现代几何造型技术的引入使其迎刃而解．本文通过对几何造型技术的研究，采用几何体素构造法对某些复合曲面进行了构造，并运用所开发的ＧＭＳ曲面造型系统进行了锻模型腔中圆弧、圆环过渡面的造型设计．     

三维几何造型在机械设计中的应用

三维几何造型是当前 CAD 技术主要课题之一,可分为线框、表面和实体三种。几何模型通过图形或数学关系来描述一个零件的形状。线框模型是三维几何造型中最简单的一种,使用计算机时间和内存也少,但不能用作复杂表面分析。描述零件复杂表面要用表面或实体模型。表面模型能揭示零件表面信息,但不能提供其内部数据。实体模型不仅定义零件的表面,而且还能揭示有关设计的内部信息。模型建立后,可以进行零件设计和制造。     

基于STEP-NC的工艺过程设计与优化技术研究

为了简化工艺决策过程的复杂性和实现工艺决策过程的模型化和算法化,在深入分析STEP-NC数据模型的基础上,针对数控工艺的特点,提出了元加工操作及制造特征加工链等概念,建立了支持非线性工艺设计的分步工艺决策过程;进而提出了基于排列和辅助时间的加工工步排序和优化的方法,实现了加工工步排序和优化过程的统一处理,使CAPP系统能够提供多个可选的工艺方案。通过一个基于STEP-NC的CAPP原型系统的实现及实例零件的工艺过程设计表明,所提出的工艺决策过程和优化方法是简单有效的。     

基于STEP-NC的特征建模及工艺设计系统研究

为了提供描述产品整个生命周期信息的统一数据模型,实现整个制造过程中产品信息的标准化,解决实现基于STEP-NC的CAD/CAPP集成问题,分析了ISO14649-10的制造特征标准定义和STEP-NC的数据模型与数据结构,提出了制造特征自动生成和STEP-NC工艺规划的一种方法,生成了STEP-NC文件。本文采用UG6.0和VC#2005软件,实现零件的设计、工艺规划和STEP-NC文件生成一体化。在统一的数据模型基础上,用STEP-NC程序建立了产品信息,保证了数据信息的集成和共享,加快了计算机集成制造系统的发展.     

基于多种CAD平台的振动筛产品开发

分析了不同CAD系统间实现数据交换的两种方法。针对新型钻井液振动筛的开发 ,使用了基于多种CAD平台下的产品设计方法 ,并对设计过程中CAD平台的选择和不同平台间的数据交换进行了分析。     

基于DXF文件的数控加工系统的实现研究

从CAD系统的图形数据库中提取零件的几何信息和工艺信息,是实现CAD/CAPP/CAM系统集成的一种方法.本文介绍了如何从AutoCAD生成的DXF文件中读取直线、圆、圆弧、椭圆弧等信息,结合面向对象的程序设计方法,将所读取的图元信息转化成数控加工代码.