知识熔接技术在管道设计中的应用研究

知识工程与CAD技术相结合是先进制造技术发展的必然趋势。利用CAD系统的用户自定义特征与KBE的工程处理能力,构建了管道智能参数化设计的基本构架,通过建立专业知识库来实现对管道模型的知识驱动,并结合工程实际给出优化方案。在此基础上,运用UG提供的KF工具开发了管道智能设计模块。     

Pro/E Wild Fire中零件库的建立方法

以Pro／E WildFire软件为基础,详细地论述了零件库的建立方法,分析了每种方法的优缺点,提出了适用范围,使零件库的建立更加简单化,从而有效的提高了实体建模速度,缩短了设计周期。     

可调式液力变矩器导轮调节特性分析

液力变矩器内部流动极其复杂,目前其CFD计算已由稳态发展到瞬态。在分析液力变矩器瞬态流场特性基础上,通过UDF和动网格技术,对导叶调节过程中变矩器瞬态流场进行了CFD计算和实验研究。研究结果表明,计算得到动态特性曲线与试验曲线误差较小,说明采用的动态特性数值计算方法是正确有效的。     

Gekoppelte Simulation zur Spezifikation von Heiz‐ und Kühlkörpern

Combined thermal building simulation for advanced heating and cooling specification. Modern concepts of buildings and rooms require a rethinking concerning conventional solutions for heating or cooling of buildings. But often it is not possible to quantify, whether a new idea is worthwhile because of missing sharpness of simple assessments. Therefore a programming system for combined thermal building simulation and indoor air flow calculation, mainly developed and successfully applied by the authors is extended by a highly resolved model for heating and cooling devices. In that way it is possible to model the specification of radiators in a test chamber or under operating conditions. In addition, the effect of cooling by radiators can be investigated. The approaches for modelling will be explained in short and some selected results are presented and discussed.     

用户自定义特征库分类模型研究*

针对传统CAD系统中用户自定义特征库分类不支持特征共享的问题,提出了基于有向无环图的用户自定义特征库分类模型。通过将特征信息作为公共子节点附加到分类树中形成有向无环图,实现了特征的分类和共享,并利用中性的XML文档实现了模型的存储,提高了模型的移植性;最后给出了模型的建立过程。实例表明,该模型简单灵活,极大地提高了用户自定义特征库的分类和共享能力。     

基于自定义特征的透平叶轮产品族参数化建模方法研究

针对制冷透平膨胀机叶轮的结构特点,以UG软件为支撑平台,运用实体建模概念,结合表达式、电子表格以及用户自定义特征等功能,提出了叶轮产品族三维参数化建模的方法,为企业实现叶轮产品的快速开发提供了一种新的途径.     

螺杆泵腔室内流场的数值模拟研究

在SolidWorks软件中建立了螺杆泵定子与转子模型,并成功地进行装配,运用Fluent提供的UDF功能建立描述螺杆泵转子运动的动网格;运用Fluent求解器对螺杆泵腔室内的非定常流动进行数值模拟,得到流场的速度分布、压力分布和应力场;分析流体粘度、转子转速以及螺杆泵偏心距对流场的影响。计算结果表明:当转子要离开定子的两端面时,泵内流场总会出现十分明显的涡流;粘度仅影响速度、压力和应力数值的大小,而对分布规律的影响不大;转子转速对速度分布影响比较大,流场速度随转子转速的增大而增大;此外,偏心距对流场有较大的影响,且偏心距越大流场参数变化幅度越大,这表明偏心距对螺杆泵的稳定性影响很大。     

基于Fluent异型模杯模具的设计

针对双子弹模压机异型模杯成型时出现的黄变、破损等问题,构建UG异型模,采用Fluent进行热流耦合数值模拟,编写UDF程序控制涡旋风入口条件,采用正交试验法进行极差分析,得出最佳异型模模具的参数.通过实测异型模具表面温度,并与数值模拟数据对比.结果表明:双子弹模压机可达到高表面质量的异型模杯成型要求,符合实际生产的模具...     

全氧燃烧玻璃熔池玻璃液的数值模拟

以优化玻璃熔窑结构,提高全氧燃烧玻璃熔窑寿命为目的,利用Fluent软件,结合配合料物性参数变化的经验公式编写UDF函数导入模型中,得到熔池内玻璃液的流动情况以及温度场、速度场.通过模拟的结果与工厂实际比较可以看出,该模型能够比较客观地反映全氧燃烧玻璃熔池中玻璃液的流动情况和温度分布,进面对窑池设计及选材具有一定的指导意义.     

Experimental evaluation of underride analysis techniques and empirical validation of a new analytical technique

Accident reconstructionists are often faced with damage patterns and locations on vehicles that are not well defined by available barrier impact data. One such example is a frontal underride collision. Underride impacts occur when there is a height mismatch between the primary structural components of the impacting vehicles, and the vehicle with the lower height is forced beneath the structure of the other vehicle. The lack of structural engagement typically allows for significantly different damage patterns due to the inherently lower stiffness of the underriding vehicle's contacting surfaces coupled with complex interactions between varying surfaces. In this study, a series of two-vehicle impact tests between a small pickup (bullet vehicle) and a large dump truck (target vehicle) were performed and studied. These tests involved a severe underride configuration in which the dump truck bed's vertical alignment was above the base of the windshield of the pickup. Coupled with these impacting surfaces was a single vertical support, a remnant of a commonly referred to ICC (Interstate Commerce Commission) bumper, which caused a narrow object-type impact, but did not extend down to the pickup's bumper. Multiple prior authors’ analytical and empirical relationships to predict impact speed based on crush damage were evaluated using the results of these tests as well as other published underride tests. No single model was sufficient at predicting the mixed mode of impact present in these impact scenarios. However, a system of equations was developed to predict the impact parameters utilizing a combination of previously reported methods and a new empirical relationship presented in this study. This new method shows high correlation and supports the authors’ hypothesis that separate crush models can be applied to multiple discrete areas of a vehicle and then combined to form a more complete predictive systematic model.