基于Pro/E Wildfire 和VC++6.0的行星锥齿轮参数化设计

介绍了在Pro/E Wildfire环境下,运用笛卡儿坐标系创建渐开线齿廓并利用其开发工具参数(Parameters)结合关系式(Relations)功能来实现行星锥齿轮参数化造型的关键技术.利用高级编程语言VC 6.0和Pro/E Wildfire的二次开发工具Pro/Toolkit,通过动态连接库,成功地实现了行星锥齿轮参数化设计系统的二次开发.     

焊管轧辊特征造型系统的研究与开发

简述了焊管轧辊三维特征造型技术的原理,并以VisualC++6.0为开发语言,在MDT环境下,利用AutoCAD中ObjectARX面向对象的开发技术,采用基于轧辊形状特征的原理,综合利用参数化设计技术,开发出焊管轧辊特征造型系统从而实现了轧辊孔型设计轧辊零件参数化绘图及三维特征造型设计的一体化     

基于CBR的飞机典型零件快速变型设计

飞机产品具有典型的品种多,批量小的特点。为了提高飞机零件设计效率,降低飞机零件的复杂程度,在参数化建模的基础上,将实例推理技术(CBR)引入到飞机零件的变型设计中。借助CATIA二次开发平台,建立飞机典型零件实例库,运用最近相邻算法计算相似度,检索出飞机典型零件实例库中与设计问题相似度最高的实例模型。利用特征造型和参数化设计相结合的三维建模方法,通过CATIA中超级拷贝功能按照新的建模基准拷贝检索出的实例模型,在已有的设计基础上,进行模型特征的更改,完成飞机典型零件的变型设计。该技术有效地减少了设计反复,提高了飞机零件的设计效率和对复杂产品的设计能力。     

基于UGNX4的自上而下参数化建模装配设计

在产品设计开发过程中,通常是完成创建装配图以确定零件配合是否合理以及产品是否按预期的设想运行.本文结合参数化特征造型方法,提出自上而下的参数化建模装配设计方法.通过简单实例,在UGNX4中建立关联几何对象,从而可以实现对设计过程的驱动,提高设计速度,减少修改设计的成本,保持设计的一致性,对实际复杂产品的虚拟设计及优化有很大的意义.     

基于UG的皮带轮压铸模设计系统研究

利用UG软件进行皮带轮模具模块的三维实体造型,以VC+ +6.0作为开发平台,结合UG/OPEN API编程技术进行UG软件的二次开发,并且引入Access2003来构建模具模块参数数据库.创建完成的设计系统可以实现模具模块的参数化建模,以及通过访问数据库直接更新零件模型,缩短了模具开发周期,提高生产效率.     

基于Pro／E的可控制起动行星齿轮减速装置虚拟样机的设计

利用Pro/E创建可控制起动行星齿轮减速装置零件的三维实体模型,通过利用Pro/E的Relations(关系式)等功能来实现齿轮的参数化建模设计,阐述了Pro/E在可控制起动行星齿轮减速装置中渐开线直齿圆柱齿轮设计中的具体应用.在二维工程图的基础上,运用三维实体造型软件Pro/Engineer对行星齿轮减速装置的各个零部件进行了三维特征造型,实现了虚拟样机的装配,为产品的生产提供了依据.     

成组技术在汽车冲压模具设计中的应用

研究了成组技术在汽车冲压模具参数化设计中的运用,分析了汽车冲压模具参数化系统的设计过程.在UG平台上开发了汽车冲压模具参数化系统,实现了零件参数库、装配模型参数库和模型管理3个部分的功能,完成了汽车冲压模具的参数化设计.     

I-DEAS环境下宏程序的应用

文章介绍了在I-DEAS环境宏程序的特点和使用方法.利用宏程序作为二次开发的工具,可以大大提高三维模型参数化设计的效率,同时满足标准化、参数化、系列化产品开发的要求.结合斜齿轮的三维建模和参数化设计,给出了宏程序的创建技术和方法.     

基于Pro／ENGINEER的化工机器零件造型设计

针对化工机器零件的特征和设计中存在的问题，应用基于特征的参数化造型软件Pro／ENGINEER对零件进行参数化造型，对造型设计技术要点进行了探讨，通过叶轮特征建模实例，实现了基于Pro／ENGINEER的参数化特征设计，提高了设计效率。     

注射模CAD参数化特征造型技术研究

参数化特征造型技术是通过规划或代数方程的形式定义尺寸或要素之间的约束关系 ,实现对已建模型的动态修改 ,可大大提高注射模设计的自动化程度。作为解决CAD/CAE/CAM接口问题的特征造型技术 ,将参数化思想和方法吸收进来 ,并有机结合 ,产生了先进的参数化特征造型方法 ,成为现代注射模CAD领域的重要研究方向。     

DYNAMIC MODELLING OF MECHANICAL STRUCTURE VIAUNDETERMINED PARAMETER METHOD

ＤＹＮＡＭＩＣＭＯＤＥＬＬＩＮＧＯＦＭＥＣＨＡＮＩＣＡＬＳＴＲＵＣＴＵＲＥＶＩＡＵＮＤＥＴＥＲＭＩＮＥＤＰＡＲＡＭＥＴＥＲＭＥＴＨＯＤＣｈｅｎＱｉａｎｇｅｎ，ＬｕｏＸｉａｏｌｉｎｇＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，...     

长管道对阀控缸液压系统动态特性的影响

通过利用管道算子将阀的压力-流量方程转换成负载的压力-流量方程,将管道的分布参数模型与阀控对称缸液压系统的模型相结合,建立起整个系统的传递函数,通过MATLAB编程绘制该系统的Bode图,并得出管道长度和内径对阀控对称缸液压系统快速性与稳定性的影响。结果表明:管道直径和内径的增加都会使系统固有频率降低,系统频响变慢;管道效应对系统中高频特性影响明显,系统中高频幅值特性出现波动,相频特性出现阶梯式滞后。     

Semi-analytical calculation of the impedance of a differential sensor for eddy current non-destructive testing

In this contribution, we aim at the modelling of the impedance of a differential sensor in eddy-current non-destructive testing. This mode of control is very common in the detection of abrupt geometrical and electromagnetic variations, disturbances generated by slow variations of dimensions and temperature being in particular not observed. We develop a direct semi-analytical model of a voltage-excited system. The formulation is based upon the use of coupled electric circuits. It provides a particular form of the differential impedance, which clarifies the role of the electromagnetic and geometric characteristics. This form of impedance will allow the investigation of non-destructive testing by means of differential sensors and will facilitate the development of real-time inversion procedures. The model is validated by results published in the literature. We exploit it in order to study various electric and geometrical parameters of the control system.     

Hole Taper Characterisation and Control in Laser Percussion Drilling

Small hole (< 1 mm diameter) drilling by lasers is widely applied in various manufacturing processes. Hole tapering is one of the inherent manufacturing problems associated with laser percussion drilling (multiple pulse drilling) whereby material is ejected in the form of molten droplets when a series of laser pulses are delivered to a point on a workpiece. This paper reports an investigation into the mechanisms of hole taper formation, its characteristics and the development of a taper control technique. A statistical modelling technique is used to characterise the parameter relationships during hole-taper formation. Laser beam inter-pulse shaping is used to control the hole-taper. Parallel holes are produced as a result of this new development.     

Methodology to improve applicability of welding simulation

Abstract

The objective of this paper is to demonstrate a new simulation technique which allows fast and automatic generation of temperature fields as input for subsequent thermomechanical welding simulation. The basic idea is to decompose the process model into an empirical part based on neural networks and a phenomenological part that describes the physical phenomena. The strength of this composite modelling approach is the automatic calibration of mathematical models against experimental data without the need for manual interference by an experienced user. As an example for typical applications in laser beam and GMA–laser hybrid welding, it is shown that even 3D heat conduction models of a low complexity can approximate measured temperature fields with a sufficient accuracy. In general, any derivation of model fitting parameters from the real process adds uncertainties to the simulation independent of the complexity of the underlying phenomenological model. The modelling technique presented hybridises empirical and phenomenological models. It reduces the model uncertainties by exploiting additional information which keeps normally hidden in the data measured when the model calibration is performed against few experimental data sets. In contrast, here the optimal model parameter set corresponding to a given process parameter is computed by means of an empirical submodel based on relatively large set of experimental data. The approach allows making a contribution to an efficient compensation of modelling inaccuracies and lack of knowledge about thermophysical material properties or boundary conditions. Two illustrating examples are provided.     

缺陷试板拉伸过程声发射信号特性的相关性分析

为了研究含不同缺陷的16MnR焊接试样的声发射信号特征参数的分布特点及相关性,制作了板状焊接试样。分别进行了含气孔、条渣、未焊透及无缺陷试样的拉伸试验。对试验中声发射信号的计数、能量和幅值的分布特点及其相关性进行了分析,得出了不同缺陷的特征参数分布特点和各参数之间的相关性。提出了运用特征参数的分布特点、相关性分析及特征参量累积分析可以确定某一类型含缺陷材料的声发射特性。但由于缺陷的形状特征、尺寸及混合特性不同,得出的特性曲线和特征点也会不同。尽可能建立多种缺陷的声发射信号特性参数的试验数据,利用各种方法对试验数据进行分析,才能为检测人员更好地评估设备的完整性提供支持。     

稀土磁性塑料充模流动过程模拟

介绍了用高压毛细管流变仪,测试研究钕铁硼磁性塑料的流变特性,并利用非线性回归分析技术得到的流变参数,建立流动本构方程和钕铁硼流变体在注射模浇注系统内的流动模型,运用该模型对磁性材料注射模流道和浇口设计、流道料的冷却凝固时间等进行优化。实验及其分析表明,钕铁硼熔料体系符合假塑性连续流体的流动特性,遵从幂律流体的流动模型,具有超高的熔体粘度,在流道内流动压降远远高于普通塑料流动压降,有其特殊的成型加工规律。     

Modelling and experimental analysis of the effects of tool wear on form errors in stainless steel blanking

The main defects that characterize the quality and accuracy of blanked parts are the form errors which can be found on the blanked surface. These defects are basically related to tool wear and process parameters. This work presents theoretical modelling of the effects of tool wear on the shearing mechanism and resulting form errors. To this end, a new parameter denominated effective clearance, which characterizes the distance between a punch and the die cutting edge when a tool is worn, is defined. An experimental analysis of form errors as a function of this new parameter is made, using 6 and 8 mm AISI A2 steel punches and 1 mm thick AISI 304 stainless steel sheet. Finally, design criteria are proposed for the process parameters to fulfil the quality requirements of blanked parts.     

Modelling of Abrasive Waterjet Machining: A New Approach

Abrasive waterjet (AWJ) machining is one of the recent non-traditional methods starting to be used widely in industry for material removal of different materials. The cutting performance of AWJ is achieved by a very high speed, small-scale erosion process. In this paper, a modified form of Finnie's model for erosion is developed for application to AWJ. This modified form is able to deal with curved surfaces rather than flat surfaces only. Furthermore, the new modelling approach is capable of simulating multiple particle erosion. This approach uses standard material properties and requires no calibration constants. The modelled results agreed well with both experimental and analytical data.     

面向原理图的液压系统自动建模与仿真技术研究

研究了在AutoCAD和Simulink下液压系统动态特性自动建模与仿真的实现问题。以AutoCAD为平台，建立了液压元件图形库和参数数据库，实现了液压系统原理图的计算机辅助绘制、元件选型和参数赋值；设计了原理图拓扑结构自动识别程序，能够自动提取液压原理图中元件的参数及相互间的连接关系，并生成数据文件。在Simulink下，建立了面向液压元件的仿真模型库。基于数据文件和仿真模型库，可以方便地实现液压系统仿真模型构建、参数赋值与仿真计算的自动化。