金属薄板螺纹底孔变薄翻边的数学分析

本文根据金属材料的机械性能，用数学分析的方法，论证了现今关于金属板材圆孔翻边的计算公式，它对于小螺纹底孔变薄翻边是不相适应的。作者应用等体积原理，推导出金属板材小螺纹底孔变薄翻边的计算公式及可借鉴的数据。     

圆孔精冲挤压翻边工艺的研究

传统的圆孔翻边工艺是在板料上预先冲出底孔．在翻边凸模和凹模的作用下,将底孔周边材料拉深形成竖直边。常以板料的底孔直径d0与翻边完成后的孔径d之比值,即Kf=d0／d来表示变形程度的大小,Kf称为翻边系数,Kf越小翻边时板料的变形程度就越大,最终越难成形。当翻边系数减小到孔的边缘濒于拉裂时,这种极限状态下的翻边系数就称为极限翻边系数,通过Kfmin表示。本文通过对传统翻边工艺难成形的工件进行工艺研究,采用全新的设计理念形成独特的圆孔挤压翻边工艺,加工出了符合要求的圆孔翻边制件。     

螺纹用变薄翻边孔的几何尺寸试验值

在板料冲压件的螺孔结构中,广泛应用变薄翻边工艺方法。通过变薄翻过,一方面增加了螺纹的接触长度,有利于零件的紧固性能,另一方面在同样螺纹接触长度的情况下,又节省了材料减轻了零件重量。 目前,由于有关变薄翻边孔几何尺寸的比较全面的资料较少,且不同的资料介绍其数据又各不一致,以致形成产品设计之间与     

移动式冲孔翻边复合模设计

深拉伸件冲底孔翻边,冲压力不大,但由于拉伸件较高,为了取放工件,需要选用行程较大的大吨位冲床,为了解决这个矛盾,本文介绍了一种在小吨位小行程压力机上使用的下模移动式冲孔翻边复合模。为类似零件的冲压探索出了一条行之有效的途径。     

TC1Mδ2.5钛板圆孔翻边成形极限与翘曲的研究

室温下用厚度为2．5mm、中心有预制底孔的TC1M钛合金圆板坯料进行圆孔翻边成形试验,结果表明：除翻边底孔尺寸小于极限值时在唇口边缘发生破裂的正常失效方式之外,卸载后翻边制件还会出现突缘平面翘曲、翻边孔口部椭圆化、口部收缩等形状翘曲现象,这些都造成钛合金薄板翻边零件无法满足尺寸和位置精度要求。在给出极限翻边系数的同时,对这种形状非轴对称化程度进行了定量描述,并给出了理论上的解释。     

TC1Mδ1·5mm钛板圆孔冷翻边极限与翘曲变形的研究

室温条件下采用有预制底孔的TC1Mδ1.5mm钛合金坯料进行圆孔翻边成形试验,结果表明,除底孔尺寸小于极限值时在唇口边缘发生破裂的正常失效方式之外,卸载后翻边制件还会出现突缘平面翘曲、翻边孔口部椭圆化、口部收缩等形状翘曲现象,这些都造成钛合金薄板翻边零件无法满足尺寸和位置精度要求。在给出极限翻边系数的同时,对这种形状非轴对称化程度进行了定量描述,并解释了此类现象产生的原因。     

高温合金冲压件翻孔成形工艺改进研究

GH536高温合金具有良好的热加工性能,但其在冷成形过程中易出现加工硬化现象。使用GH536高温合金材料的高翻边孔冲压件在一般翻孔工艺成形过程中,会出现翻孔边缘开裂和翻孔竖边高度达不到要求的问题。通过分析冲压件在一般翻孔工艺过程中产生以上问题的原因,对一般翻孔工艺进行改进,采用先拉伸再冲孔后翻孔的新工艺。使用DYNAFORM软件模拟冲压件在新工艺条件下的翻孔成形过程,并根据材料变形的特点及翻边孔的质量,确定翻孔工艺的新方案,解决高温合金材料的高翻边孔冲压件在翻孔成形过程中孔开裂和翻孔竖边高度达不到要求的问题。     

影响孔翻边质量的因素及对策

<正> 1 孔翻边的应力应变状态 八号小口瓶铁壳铝底孔翻边的工序是采用先拉伸冲底孔再翻边的方法,如果我们在预冲孔周围画出若干等距离圆环,则翻孔后可以发现圆环之间的距离变化不大,但圆环本身却大大的伸长了。通过对翻孔壁上取下单元体进行应力分析(图1),就可以知道金属材料在切向和径向都受到拉伸应力,以切     

汽车冲压件翻边缺陷的解决方案

在冲压件的生产过程中,翻边缺陷较为常见,严重影响了冲压件的品质,快速解决此类问题显得尤为重要。以一个典型的案例对汽车冲压件翻边产生的起皱现象进行了分析,详细介绍了两个不同的方案来优化零件的成形工艺、整改模具结构和现场调试的结果。通过这两个不同方案介绍了对于在不同情况下解决此类问题的选用依据,以便有效地避免产生缺陷。     

大孔径冲孔翻边一次成型的设计

此文主要根据冲压件“前顶梁”冲孔翻边一次成型模设计的实践经验，提出大孔径冲孔翻边一次成型的工艺分析和计算及典型结构的设计，突破了冲孔与翻边同时进行只能在Ф８以下圆孔翻边的局限，并成功地一次试模合格，为类似的圆孔翻边在Ф８以上提供了宝贵的经验。     

无心磨削工艺参数的非线性优化研究

为了选择无心磨削的最佳工艺参数,通过对其加工原理及工艺参数进行分析,在满足产品技术要求和磨削加工条件等设计约束的前提下,建立磨削工艺参数优化的非线性数学模型。应用MATLAB优化工具箱对工艺参数进行优化计算,得到最佳的工艺参数。优化后的工艺参数使得单位时间内的金属切除率大幅度提高,优化计算的结果验证了此方法的有效性。     

柔性机座-转子系统动力学参数优化仿真

以M701F重型燃气轮机转子系统作为研究对象,建立柔性机座-转子系统动力学模型;计入柔性机座-转子系统动力学参数全局性变化范围,提出全局匹配分析方法并实现了动力学参数全局最佳匹配数值计算软件系统;通过跟踪研究计入全局动力学参数下机座动力参数最佳匹配点和轨迹的变化规律,揭示不同转子动力学参数下机座参数最佳匹配点轨迹特征,...     

Sensitivity analysis of submerged arc welding process parameters

Selection of process parameters has great influence on the quality of a welded connection. Mathematical modelling can be utilized in the optimization and control procedure of parameters. Rather than the well-known effects of main process parameters, this study focuses on the sensitivity analysis of parameters and fine tuning requirements of the parameters for optimum weld bead geometry. Changeable process parameters such as welding current, welding voltage and welding speed are used as design variables. The objective function is formed using width, height and penetration of the weld bead. Experimental part of the study is based on three level factorial design of three process parameters. In order to investigate the effects of input (process) parameters on output parameters, which determine the weld bead geometry, a mathematical model is constructed by using multiple curvilinear regression analysis. After carrying out a sensitivity analysis using developed empirical equations, relative effects of input parameters on output parameters are obtained. Effects of all three design parameters on the bead width and bead height show that even small changes in these parameters play an important role in the quality of welding operation. The results also reveal that the penetration is almost non-sensitive to the variations in voltage and speed.     

电火花加工工艺参数的优化及其应用

论述了在电火花加工中工艺参数对工艺效果的影响关系和目前常用的工艺参数优化的方法。介绍了KBE技术及其在电火花加工工艺参数优化中的应用前景，提出应用KBE技术将为电火花加工的工艺参数优化提供比较完美的解决方案。     

Optimization of spray conditions in cold spraying based on numerical analysis of particle velocity

The effects of the parameters involved in cold spray on the acceleration of particles are systematically investigated by a CFD code in order to reveal the main factors influencing significantly particle velocity. The parameters involved include nozzle geometry parameters, processing parameters and properties of spray particles. It is found that driving gas type, operating pressure and temperature are main processing parameters which influence particle velocity. As for nozzle geometry, the expansion ratio and divergent section length of spray gun nozzle show significant effects. Moreover, the density, size and morphology of powder also have significant effects on particle velocity. The effects of those main parameters are summarized in a comprehensive equation obtained through nonlinear regression of the simulated results for the estimation of particle velocity. The interactions of the parameters on particle acceleration can be examined through the equation. Moreover, the optimization of the dimensions of spray gun nozzle and spray parameters can be realized based on the obtained results.     

螺旋埋弧焊管焊缝形状参数分析

螺旋焊管焊缝形状的好坏,直接影响焊缝接头服役时的力学性能、焊缝的内部质量以及防腐涂层的成本,并反映焊接工艺参数选择的合理性。分类描述了焊缝形状的几何参数（选择性参数和操作性参数）,重点论述了焊缝的余高、熔宽、熔深、熔合比、重合度、过渡角、错边量、焊偏量等参数及其对焊接质量的影响。     

Modeling and measurement of active parameters and workpiece home position of a multi-axis machine tool

The complex structures of a multi-axis machine tool may produce inaccuracies at the tool tip caused by dimensional errors in the machine's link parameters. This paper addresses two important issues for precision machining: (1) which link parameters (denoted as active parameters) of a machine tool can affect the machining accuracy of a workpiece and (2) how to measure the active parameters by using a grinding wheel as a measuring probe. To achieve this, a modified Denavit–Hartenberg (D–H) notation is introduced to model a multi-axis machine tool. The NC data equations are then derived in terms of the machine's link parameters. It is found that the link parameters of a machine tool can be divided into two types: active and nonactive parameters. The prerequisite for obtaining an accurately machined workpiece is to have correct values of the active parameters and the workpiece home position. Based on the developed NC data equations of a multi-axis machine tool, this paper also addresses the technique of using a grinding wheel as a measuring probe to determine the active parameters and the workpiece home position. Experimental results are also given with illustrative examples.     

A study of the process of continuous forming of nanocrystalline composite powders

Results of a theoretical and experimental study of the process of continuous forming of nanocrystalline powder materials for making long-length articles with nanocrystalline structure are presented. The laws relating the energy and force parameters of the process and the geometric parameters of the tool are determined. Relations for minimizing the energy and force parameters of the process by optimizing the geometric parameters of the tool are obtained.     

附加参数与基本参数空间关系的度量

合理地选择参数,避免参数间的强复共线性,是参数有效估计的关键之一。通过将参数Ｘ分为两类,即基本参数Ｘ１和附加参数Ｘ２。并假定附加参数的选取不当是造成参数间强复共线性的主要原因,提出了用点（Ｘ２中的一列向量）到空间（由Ｘ１所对应的列向量张成Ｈｉｌｂｅｒｔ空间的子空间Ｈ０）夹角的正弦值作为度量标准来优选附加参数,给出了该方法的理论论证,并用两个算便对度量方法进行了验证和说明。     

PMSM控制器参数自整定研究

文章研究永磁同步电动机( Permanent Magnet Synchronous Motor,PMSM)转速电流双闭环控制系统控制器参数的自整定方法.电流环根据辨识得到对象参数按照工程设计方法进行整定.速度环采用模糊自整定的方法.根据速度响应的超调量和调节时间,经模糊化、模糊推理和清晰化得到控制器参数调整量,从而改变速度控制器参数,直到满足指标要求,最后将参数固定.实验表明,该方法改善了速度响应性能,实现了永磁同步电机安装后伺服驱动控制器参数的快速自整定.