注塑成型工艺对包塑成型嵌件变形的影响

利用ANSYS Workbench软件对汽车接插件成型过程中嵌件受力变形进行分析,分析细针状嵌件在注塑成型过程中的变形情况。采用包塑成型的优化工艺方案,先设计一个工艺过渡件,对细针状嵌件进行定位,再将工艺过渡件以嵌件的形式进行注塑成型,并对其嵌件受力进行分析。实际生产表明,应用包塑成型重叠注塑工艺可以提高产品质量,使其满足使用要求。     

基于FEM的可转位浅孔钻几何参数的优化

建立了刀体与刀片的坐标系，定义出可转位浅孔钻的五个主要安装角度，并对其进行优化，得到径向合力近似为零的结果。为浅孔钻的结构设计和进一步研究钻削力、钻削温度等提供了依据。     

有关金刚石钻进原理的研究

结合试验研究及国内外经验，提出以控制钻头切入量为准的钻进规范，获取最优化钻进；依据增大切入量原则，分析论述研究优质大粒聚晶体的必要性和可能性，突破现用金刚石钻进的局限；分析了当前专业技术状况，提出加强科学试验和研究的重大意义。     

管内插物强化换热性能分析及应用

管内插物的种类很多，扭带、螺旋线圈以及绕花丝是三种较常用的管内插物强化换热技术，对它们的强化换热性能以及应用进行分析比较，是非常有必要的。从综合强化性能来看，螺旋线圈内插物比扭带内插物效果好；绕花丝内插物是一种新型综合强化换热技术，它优于前两种内插物的特点是：可使流体在流动方向上做复杂的三维混合流动，并且所产生的阻力降非常小，所以综合强化换热性能最好。图7表1参10     

G308、YJ2.1R硬质合金在复合钎头上的应用

介绍了G30 8、YJ2 .1R新型凿岩硬质合金的物理机械性能 ,并就镶嵌该 2种硬质合金的飞龙 4 0、 4 2 -4PIC锥体连接复合钎头 ,与我国目前广泛流行的镶YG11C硬质合金片的 4 0、4 2mm“一”字形钎头在同一场地进行了对比应用     

Theoretical, numerical, and experimental modal analysis of a single-winding gradient coil insert cylinder

The objective of this paper is to find the relatively low-frequency (200–2,000 Hz) mode shapes of a single-winding gradient coil cylinder with intermediate wall thickness. The dynamic behavior of a gradient coil cylinder plays a crucial role in determining and controlling the vibroacoustic performance of magnetic resonance imaging (MRI) scanners. Modal analyses of the gradient coil cylinder were carried out under different boundary conditions to obtain the various mode shapes. Theoretical modes, predicted by using modified Love’s governing equations, and numerical modes simulated using a finite element method show close agreement with experimental modal results and reveal the mode shapes for both free-end and fixed-end boundary conditions. These results were further compared to in situ measurements of the mode shapes of the gradient coil cylinder insert during scanning in a 4 Tesla MRI. The general agreement among the analytical, numerical, and experimental mode shapes indicates that a linear combination of basic beam vibration and ring vibration patterns occupy the dynamic vibration modes in the low frequency range. The in situ vibration measurements show that the forcing function developed by the distributed Lorentz forces on the surface of the single-winding gradient coil results in predominantly beam-type bending mode patterns in the low frequency range.     

高温环境下蜂窝夹层结构埋件拉脱性能研究

介绍了常温环境下和高温环境下蜂窝夹层结构埋件拉脱性能的试验和结果,对比分析了高温环境对埋件拉脱性能的影响。结果发现,埋件在受法向拉脱力时,高温环境中承载力下降为常温的8%左右,且失效模式也发生了变化,由常温的蜂窝芯剪切破坏变为面板与蜂窝芯脱粘破坏;埋件在受面内拉脱力时,常温环境和高温环境下埋件分别呈现出了两种典型的失效模式,常温环境中失效模式为面板压缩破坏,高温环境中失效模式为面板皱褶失稳破坏,且拉脱力降为常温的28%左右。     

Substrate treatments/modifications to improve the adhesion of diamond-coated cutting inserts

In this paper we first describe the basic idea of adhesion and various methods for measuring adhesion. We then discuss the various state-of-the-art techniques for the improvement of the adhesion between diamond films and substrates. The techniques discussed are categorized into two main types: (a) those which reduce internal stress and (b) those which increase the ideal or basic adhesion itself. Techniques in category (a) include forming a composition gradient layer on top of an insert substrate surface to reduce the detrimental effect caused by the difference in thermal expansion with diamond, and/or the use of insert substrates themselves having a smaller difference in thermal expansion with diamond. Techniques in category (b) include modification of cemented carbide substrates so as to reduce the detrimental effect caused by Co and the increase of the mechanical interlocking effect using a special etching process.     

Effect of MgO particle size on the microstructure, mechanical properties and wear performance of ZTA-MgO ceramic cutting inserts

The mechanical properties, microstructure and wear performance of zirconia-toughened alumina (ZTA) cutting inserts with Magnesia (MgO) in different particle sizes as additives was investigated. The MgO particle sizes were varied from 80 nm to 7000 nm. The alumina (Al₂O₃), yittria stabilized zirconia (YSZ) and MgO powders were mixed, compacted and sintered at 1600 °C using the solid-state sintering method. The mechanical and physical properties of the samples such as wear resistance, Vickers hardness, fracture toughness, microstructure and density were analyzed. Commercially available stainless steel (316L) was used as the workpiece for the wear resistance study. It was observed that smaller MgO particle sizes induce better wear performance and mechanical properties for the cutting inserts. Wear resistance analysis showed that the cutting insert with nano-sized MgO (particle size 80 nm) had the lowest wear area of 0.019 mm². The same cutting insert also possessed the highest Vickers hardness value of 1740 Hv compared to the other samples. Furthermore, microstructural observations show that the Al₂O₃ grain size depends on the particle size of MgO, and is directly related to its hardness property.     

超声弯曲工具头的动态特性仿真与实验研究

牙种植超声工具利用弯曲工具头能够制备异型种植窝孔,为了研究工具头弯曲角度对位移响应的影响,利用有限元软件Abaqus对弯曲工具头进行动态仿真,得到不同弯曲角度工具头的位移响应,并通过实验验证有限元分析结果。验证实验表明,有限元分析结果与实验结果基本保持一致,为具有弯曲工具头的牙种植超声工具的设计提供了方法和依据。