精密冲裁力的滑移线法计算

在分析精密冲裁的基础上，运用滑移线理论推导了计算精密冲裁力的理论公式，并通过实例验证，该公式比常用的计算公式更接近实际值。     

侧刃的成形冲切

论述了变普通标准侧刃为成形侧刃、落料侧刃，从而将有搭边排样的有废料冲裁转变为无搭边排样的无废料冲裁或无搭边小沿边排样的少废料冲裁的方法。     

大间隙薄板冲裁模的设计与应用

该文讨论了薄板冲裁的特点，分析了冲裁变形的过程，简述了设计方法，重点介绍了大间隙薄板冲裁模的结构及主要工艺参数的确定。     

少无废料冲裁在电机零件生产中的应用

通过对少无废料冲裁的应用研究,分析了少无废料冲裁在电机零件生产中的应用,介绍了一种少无废料冲裁模结构,总结了少无废料冲裁应用的效果,对电机制造厂降低成本有一定的借鉴意义。     

大间隙薄板冲裁模的设计与应用

讨论了薄板冲裁的特点，重点介绍大间隙薄板冲裁模的结构及主要工艺参数的确定。     

无废料冲裁模

<正> 冲裁的工件如图1所示,排料为交叉排料。图2所示为无废料冲裁模。一般无废料冲裁模定位档料与出料较为困难。图2所示的模具结构,采用了一种档料机构解决了档料与出料的问题,达到了无废料冲裁。     

精密冲裁力理论计算公式推导

在分析精密冲裁的基础上运用滑移线理论推导了计算精密冲裁力的理论公式，并通过实践证明了该计算公式比常用的计算公式更接近实际值。     

聚氨酯橡胶在冲裁模中的应用

通过对聚氨酯橡胶用作薄板类冲压件冲裁凹模的工艺分析，探索了减小薄板类零件冲裁毛刺，提高零件表面质量的方法。     

冲裁凸模抗压弯能力校核的探讨

针对冲裁凸模抗压弯能力校核问题,在理论推导并结合实例计算验证的基础上进行了探讨,可为冲模设计人员提供理论上的指导,依据材料力学中杆件受轴向压力的Euler公式及压杆稳定的校核条件,推导出冲裁凸模纵向抗弯强度校核公式的一般形式,再结合冲裁凸模的结构及工作条件,得到冲裁凸模在有导向装置和无导向装置下符合实际工作情况的一组校核公式,最后以一凸模为例,对该公式进行了验证。     

基于剪切面分析的冲裁模具磨损预测

针对薄板冲裁过程中模具与板料的摩擦分析,推导出凸模侧壁的摩擦力公式,得到了板料剪切面光亮带与凸模侧壁磨损之间的量化关系。在此基础上,建立凸模磨损的灰色预测模型,并采用端子高速冲裁试验,对该模型进行验证,通过比较实际磨损值与模型预测值以及残差计算,证明了该模型对于凸模磨损预测的准确性。     

材料的塑性泊松比μp和弹塑性泊松比μep

本文在塑性变形体积不可压缩的条件下导出了以塑性应变εｐ定义的塑性泊松比μｐ和以弹塑性总应变εｅｐ定义的弹塑性泊松比μｅｐ的计算式,指出在小变形范围内可以看作μｐ＝０．５,而μｅｐ则总是小于０．５;当变形较大时,无论是μｐ还是μｅｐ均远小于０．５。本文提供的计算式可用于解决大变形问题     

Inference of plastic deformation in weldment with parallel cracks from infrared thermography

Tensile tests are carried out by using the welded plate with two parallel cracks. The effects of the residual stress, the hardened zone by welding and the interaction between cracks on the plastic deformation near cracks and the crack opening displacement are examined by the experiment as well as the elasto plastic finite element analysis. A new technique for evaluating nondestructively the plastic deformation near cracks by using the infrared thermography is proposed. The heated region and the temperature rise measured by the thermography are compared with the plastic zone and the work of plastic deformation obtained by the analysis. The validity and the limitations of the application of the infrared thermography to the evaluation of the plastic deformation are discussed.     

基于塑变成筒壁环料的筒件成形工艺分析——简介“一种筒形件成形工艺分析方法”的发明专利

与国内外现行的以各类经验数表为标准进行参照估算设计的方法不同,提出了以在成形过程中实际塑变成筒壁的环形材料为研究对象,把拉深过程看成是筒周长×环宽的(矩形)基本材料吸收消化其余三角形材料的过程,从而得到环料变形的基本特性因子(b/d)lg(b/t).以实验数据为依据.基于变化规律和数量关系建立起关于拉深极限、拉深力、压边力、拉深次数、圆角选取、坯料修正和内孔翻边以及带缺口或凸耳的简件直接拉深成形等工艺分析问题的数学公式.该方法将工艺分析从经验数表参照估算改为公式计算精确判定,形成了一个完整的分析计算体系,能够满足生产的实际要求,可作为编制先进计算机应用软件的技术基础.     

厚板滚弯回弹计算新方法

理论分析表明板材弯曲时后继变形中弹性变形所占比例较大,对于Q235而言,其比例达到了10％.新的回弹计算方法考虑了板材后继变形中弹性变形.将文献回弹公式、新的回弹公式与实际使用的经验公式和数值模拟进行对比,对比结果表明：新的回弹公式介于模拟结果与经验公式之间,更接近于经验公式,并且误差在10％以内,成形内半径越大,新旧方法之间的差距越大,新方法的优势越明显.     

爆炸焊接波状结合区塑性变形机理的计算分析

爆炸焊接结合区产生大的塑性变形及波状结合,是爆炸焊接工艺的主要特征,也是实现良好冶金结合的必要条件。但是,塑性变形及波状结合的形成机理尚不明确。该文引入牛顿应力公式到弹塑性模型,以近似描述结合区材料行为,建立了连续介质模型,对波状结合区的塑性变形及爆轰速度对塑性变形的影响进行计算分析,并与试验结果对比。结果表明,结合界面呈波形,结合区材料产生大量的塑性变形,并且向界面集中,变形集中的区域沿爆轰方向由宽变窄,材料变形量逐渐增大;随着爆轰速度的增大,界面变形区域扩大,且变形量增大。     

弹塑性变形对张力辊电机扭矩的影响

根据弹塑性变形耗散能量的理论基础，对张力辊进行了受力分析，得出张力辊在电动和发电两种状态下电机扭矩的计算公式，并给出弹塑性力的计算公式，为今后张力辊电机扭矩计算提供更加精确的理论计算依据。     

用有限元逆算法计算板料成形毛坯形状和应变分布

针对传统的毛坯展开方法所存在的问题 ,本文采用形变理论并利用理想形变的假设 ,导出用于板料成形设计的逆算法。理想形变假设认为变形是在整体塑性功取得相对极值的条件下得到的 ,文中给出了理想形变的数学公式和有限元表达。将此数值方法的结果与实验数据对照 ,得到了满意的结果     

Determining mechanical characteristics of material resistance to deformation in machining

This paper analyses experimental results and different hypotheses about the resistance of the machined material to plastic deformation in machining. It is necessary to take into account that strain rate and temperature affects the mechanical properties of the material. It is useful to describe the regularities of material resistance to plastic deformation with differential equations, determining a dependence of the specific deformation work on deformation. For machining processes, the correlations between yield point and deformation or rather flow curves are analytically deduced from the differentiation of the specific deformation work. It has been found out that the flow curves are vaulted for the adiabatic conditions of deformation in the chip forming area and the accumulation zones near the cutting edge. The yield point here reaches its maximum for deformations that are usually lower than the true final shear of the material penetrating through the chip forming area. It is suggested to take these maximum values of the yield point as mechanical properties of the material to be machined. The main goal of the theoretical and experimental investigations presented in this paper is to establish the analytical dependence of the specific deformation work and therefore also of yield point and specific tangential forces on deformation, taking account of the effect of temperature on yield point. The main advantages of applying the specific deformation work is not only its direct relation to deformation temperature but also the possibility of experimentally determining this work through specific tangential forces and true final shear. In this way it is possible to establish how deformation temperature affects yield point by means of empirical constants.     

RESEARCH ON THE EVALUATION METHOD OF FRICTION AND LUBRICATION IN DEEP DRAWING

1.BasicPrincipleOfSheetMetalFO~['~']Sheetmetalfondngisafoeingmethodthatcanhansformtheblankintoathree--dimensionalPart.Therearesevensdefonnationpatternsinsheetmetalfoeing,suchasbending,stretchinganddeep~ng.InaPinebendingpcness,thestainsandsacssescanbedividedintotwOacs.Inawidestrip(widththicknessratiob/t>3)bendingp~ess,stainsofinnerandouterlayersarebe--dimensional,stressareplain,whileinanarrowstrip(widththicknessratiobit$3)bendingpcness,sabinsOfinnerandouterlayersareplain,snessarehoe--dimens…     

Investigation of Strain Rate Effect by Three-Dimensional Discrete Dislocation Dynamics for fcc Single Crystal During Compression ProcessEI北大核心CSCD

Microelectromechanical systems (MEMS) have become increasingly prevalent in engineering applications. In these MEMS, a lot of micro-components, such as thin films, nanowires, micro-beams and micropillars, are utilized. The characteristic geometrical size of those components is at the same scale as that of grain, the mechanical behavior of crystal materials exhibits significant size effect and discontinuous deformation. In addition, those MEMS are often subjected to high strain rate at work, such collision and impact loading. The coupling deformation characteristics of small scale crystals and high strain rate makes their mechanical behavior more complicated. Accordingly, investigation of the effect of the strain rate on crystal materials at micron scale is significant for both the academia and industry. In this work, a plastic deformation model of fcc crystal under axial compression was developed based on three-dimensional discrete dislocation dynamics (3D-DDD), which considered the influence of externally applied stress, interaction force between dislocation segments, dislocation line tension and image force from free surface on dislocation movement during the process of plastic deformation. It was applied to simulate the plastic deformation process of a Ni single crystal micropillar during compression under different loading strain rates. 3D-DDD and theoretical analysis are carried out to extensively investigate the effect of strain rate on flow stress and deformation mechanisms during plastic deformation process of crystal materials. The results show that the flow stress and the dislocation density increased with the loading strain rate. In the case of low strain rate, the flow stress was dominated by the activation stress of FreakRead (FR) source in plastic deformation. With the increase of strain rate, the contribution of activation stress of FR source to the flow stress decreases and the effective stress gradually dominated the flow stress. Under high strain rate loading, with the increase of the initial FR source, the dislocation density also increased at the same strain correspondingly, which makes it easier to meet the requirement of the loading strain rate, so the flow stress is smaller. In addition, under the low strain rate loading, a few activated FR sources can meet the requirement of the plastic deformation, a single slip deformation come up as a result. While, as the loading strain rate increases, more and more activated FR sources would be needed to coordinate the plastic deformation, the deformation mechanisms of the single crystal micropillar transformed from single slip to multiple slip.