前桥锁销孔加工机床

文章介绍了一种新型的前桥锁销孔加工的工艺方法.通过对前桥锁销孔加工工艺方法的分析、调查研究,以及大量的生产实践的验证,提供了一种新型的铣削交叉孔的加工工艺方法.该方法具体应用为:一工位用钻头加工实体部分;二工位用铣刀加工两孔相交部分;三工位用钻头钻通孔余下部分;四工位用铰刀通铰全孔.经过一系列的改进,成功地加工出合格的产品,为高精度交叉孔的加工提供了一种新工艺.     

翼子板拉延模具型面优化设计及成形模拟

根据覆盖件拉延成形工艺补充面、压料面和拉延筋的设计原则和方法，设计出了翼子板拉延件。并运用有限元软件Dynaform对拉延成形过程进行分析，根据模拟结果对拉延型面进行修改、优化，最终得到合理的模具型面用于模具加工制造。     

INTERACTION BETWEEN Cu AND LIQUID Sn——Also on Physical Meaning of Wetting Curve

用显微结构方法研究了Cu与液态Sn的相互作用;作出了浸沾时间与Cu溶解扩散的关系图。温度升高至350℃时金属间化合物Cu_6Sn_5的生长有突跃,以羽毛状迅速生长并突破沾Sn层。研究了抑制金属间化合物生长的各种方法。根据上述研究,详细讨论了meniscograph方法所得润湿曲线的物理意义。     

Sn-Zn系无铅钎料的研究现状及发展趋势

介绍了Sn-Zn系无铅钎料的研究及应用现状,阐述了为改善Sn-Zn无铅系钎料存在的不足之处,添加各种合金元素或微量元素如Bi,Ag,In,Ga,Al,RE等元素后,对Sn-Zn系无铅钎料钎焊性能、力学性能的影响以及Sn-Zn系无铅钎料界面反应及界面金属间化合物(IMC)的研究现状.简要综述了国内外有关Sn-Zn系无铅钎料专用助焊剂的研究状况,对Sn-Zn系无铅钎料今后的研究、改进及应用方面的前景和发展方向进行了分析与预测.     

客车前大灯支架加强板工艺改进

对客车前大灯支架加强板原工艺进行分析，并进行工艺改进，且对改进的每道工序的模具进行合理设计，模具设计较完善，实际应用效果良好。     

FATIGUE LIVES FOR INDUCTION HARDENED SHAFTS MATERIALS ACCORDING TO THE ENVIRONMENTAL TEMPERATURES

Rotary bending fatigue tests were carried out with two kinds of materials, S43C and S50C, using the front engine and front drive shaft （FF shaft） of vehicle. The specimens were induction hardened about 1.0mm depth from the specimen surface, and the hardness value on the surface was about HRC56-60. The tested environment temperatures were -30, 25 and 80℃ in order to look over effect of the induction hardening and the environmental temperatures on the fatigue characteristics. The fatigue limit of induction hardened specimens increased more about 45% than non-hardened specimens showing that the endurances of S43C and S50C were 98.1 and 107.9MPa in non-hardened samples, 147.1 and 156.9MPa in hardened samplesrespectably. The maximum tensile and compressive stress on the small circular defect was about ＋250 and -450MPa respectively when circular defect is situated on top and bottom. The fatigue life increased 80, 25 and -30℃ in order regardless of hardening. In comparison of the fatigue lives on the basis of tested result at 25℃, the fatigue lives of non-hardened specimens decreased about 35%, but that of hardened specimens decreased about only 5% at 80℃ more than at 25℃. And fatigue life of non-hardened and hardened specimens were about 110% and 120% higher at -30℃ than that of 25℃. Based on the result of stress distribution near the defect, the tensile and compressive stress repeatedly generated by load direction were the largest on the small circular defect due to the stress concentration.     

An object oriented implementation of a front tracking finite element method for directional solidification processes

This paper focuses on the numerical simulation of phase‐change processes using a moving finite element technique. In particular, directional solidification and melting processes for pure materials and binary alloys are studied. The melt is modelled as a Boussinesq fluid and the transient Navier–Stokes equations are solved simultaneously with the transient heat and mass transport equations as well as the Stefan condition. The various streamline‐upwind/Petrov–Galerkin‐based FEM simulators developed for the heat, flow and mass transport subproblems are reviewed. The use of classes, virtual functions and smart pointers to represent and link the particular simulators in order to model a phase change process is discussed. The freezing front is modelled using a spline interpolation, while the mesh motion is defined from the freezing front motion using a transfinite mapping technique. Various two‐ and three‐dimensional numerical tests are analysed and discussed to demonstrate the efficiency of the proposed techniques. Copyright © 1999 John Wiley & Sons, Ltd.     

Q‐Morph: an indirect approach to advancing front quad meshing

Q‐Morph is a new algorithm for generating all‐quadrilateral meshes on bounded three‐dimensional surfaces. After first triangulating the surface, the triangles are systematically transformed to create an all‐quadrilateral mesh. An advancing front algorithm determines the sequence of triangle transformations. Quadrilaterals are formed by using existing edges in the triangulation, by inserting additional nodes, or by performing local transformations to the triangles. A method typically used for recovering the boundary of a Delaunay mesh is used on interior triangles to recover quadrilateral edges. Any number of triangles may be merged to form a single quadrilateral. Topological clean‐up and smoothing are used to improve final element quality. Q‐Morph generates well‐aligned rows of quadrilaterals parallel to the boundary of the domain while maintaining a limited number of irregular internal nodes. The proposed method also offers the advantage of avoiding expensive intersection calculations commonly associated with advancing front procedures. A series of examples of Q‐Morph meshes are also presented to demonstrate the versatility of the proposed method. Copyright © 1999 John Wiley & Sons, Ltd.     

Interfacial properties of polyacrylamide solutions

Surface tension of the polyacrylamide solution was measured as a function of the polyacrylamide concentration (0–1000 gm/m³) and temperature (10–60°C). The static contact angles of the polyacrylamide solutions in the range of 0–1000 gm/m³ were reported on the polyvinyl chloride and Teflon substrates. Surface tension, static contact angle, and spreading behavior of the polyacrylamide solutions in the presence of different concentrations of NaCl, CaCl₂, and AlCl₃ are discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 219–227, 1999     

双振子系统的动力学分析

用经典力学建模和数形结合的方法,分析了一道常见的关于恒力作用下双振子振动的问题,解释和廓清了相关的概念,并将此问题的提问扩展,从而使原题更完整而具有趣味。