Application of Runge–Kutta–Rosenbrock Methods to the Analysis of Flexible Multibody Systems

Numerical integration methods are discussed for general equations of motion for multibody systems with flexible parts, which are fairly stiff, time-dependent and non-linear. A family of semi-implicit methods, which belong to the class of Runge–Kutta–Rosenbrock methods, with rather weak non-linear stability properties, are developed. These comprise methods of first, second and third order of accuracy that are A-stable and L-stable and hence introduce numerical damping and the filtering of high frequency components. It is shown, both from theory and examples, that it is generally preferable to use deformation mode coordinates to global nodal coordinates as independent variables in the formulation of the equations of motion. The methods are applied to a series of examples consisting of an elastic pendulum, a beam supported by springs, a four-bar mechanism, and a robotic manipulator with collocated control.     

Recurrent Neuro-Fuzzy Modeling and Fuzzy MDPP Control for Flexible Servomechanisms

This paper considers the nonlinear system identification and control for flexible servomechanisms. A multi-step-ahead recurrent neuro-fuzzy model consisting of local linear ARMA (autoregressive moving average) models with bias terms is suggested for approximating the dynamic behavior of a servomechanism including the effects of flexibility and friction. The RLS (recursive least squares) algorithm is adopted for obtaining the optimal consequent parameters of the rules. Within each fuzzy operating region, a local MDPP (minimum degree pole placement) control law with integral action can be constructed based on the estimated local model. Then a fuzzy controller composed of these local MDPP controls can be easily constructed for the servomechanism. The techniques are illustrated using computer simulations.     

基于LabVIEW的虚拟双参数核谱获取系统设计

主要介绍利用最新图形化编辑环境LabVIEW平台和NI公司的多功能数据采集卡进行双参数核谱获取与分析的应用研究。     

灯泡贯流式水轮发电机组轴系振动及静挠度计算分析

灯泡贯流式水轮发电机组一般采用卧轴结构，本通过对大轴可能存在的载荷工况进行了全面分析，得出了影响卧式轴系的主要运行工况，为设计和安装提供了技术支持。     

瑞典的职业教育--专业与课程设置分析

瑞典的职业教育，专业和课程设置富有灵活性。以提供基础教育为理念，重视学生基本素质、基本能力的提高。学生享有高度选择自由。     

Effects of superstructure flexibility on strength of reinforced concrete bridge decks

This research studies the impact of the relative rigidity between the concrete bridge deck and the remaining structural components of the bridge superstructure on the behavior of the concrete deck. The study uses non-linear 3-D FEM models, which are developed using ANSYS 5.7 software package. Experimental data from one-span non-composite bridge superstructure are used to validate and calibrate the proposed FEM models. A series of parametric studies is conducted with respect to three parameters: (a) composite action, (b) slenderness ratio, and (c) presence of diaphragms. The analysis results are discussed in detail and conclusions on the behavior of the bridge deck are presented.     

各向异性柔性粘结NdFeB磁体的研制

通过不同的工艺路线制备了各向异性柔性黏结NdFeB磁体,并且分析了影响各向异性柔性黏结NdFeB磁体的因素。试验结果表明,通过溶解造粒和脉冲磁化以及磁场压延等工艺能够显著提高磁体的磁性能。     

三聚氰胺甲醛树脂改性及其纤维的性能

三聚氰胺甲醛树脂是热固性高聚物,成纤性差,成纤纤维韧性差;通过苯代三聚氰胺、聚乙烯醇(PVA)对三聚氰胺树脂进行改性,提高了树脂溶液的可纺性,所制纤维的柔韧性得到了提高。通过红外光谱、SEM、TG-DTA研究了纤维的结构、形态及耐热性。     

电力企业工作流管理系统的设计与实现

介绍了适合电力企业的工怍流管理系统的设计方案和实现方法,并指出了系统的特点。系统采用一种面向用户的工作流建模方法,弥补了Petri网方法的图形复杂和节点多的不足。系统支持工作流实例的动态变化,符合电力企业业务工作流的需要。     

分布式柔性工作流的研究与实现

工作流的柔性问题已经成为工作流研究领域的一个重要方面。笔者首先讨论了实现柔性的必要性，具体分析了柔性的分类。在此基础上给出了应用面向对象的概念和RMI技术来实现这一课题的详细方案。原形系统是基于C/S架构和RMI、采用Java语言开发的。系统中各客户独立地运行在各自的系统机上，通过分布式工作流引擎灵活的调度、控制、柔性协同地完成共同的目标。