舰船用水润滑轴承微观界面润滑机理研究

针对水润滑轴承微观界面润滑状态和润滑机理存在的不清楚、不明朗等问题,开展微凹痕对轴承微观界面润滑机理影响的研究。在建立单一微凹痕内部流体动力学模型的基础上,研究微凹痕内部涡流结构变化特性,分析微凹痕内部流场动力学特征,讨论形貌特征参数与润滑性能的变化规律,证明流体动力学特性随表面形貌的演化规律,验证微凹痕对轴承微观界面润滑机理的影响规律,从而提出微尺度下水润滑轴承润滑理论,并从微观层面探究粗糙峰与轴承润滑状态转变之间的关系,进而提出判断润滑状态转变的微观尺度标准。结果表明,微动压效应、微空化效应、微惯性效应三者共同构成水润滑轴承微观界面的润滑机理,大量微凹痕累积进而可以增强轴承承载能力、降低摩擦功耗。     

凹槽形补焊缝维氏硬度的梯度试验

在铸钢件补焊工艺评定时,要求对试样中的焊缝、热影响区、母材部位进行维氏硬度的梯度试验。硬度压痕与压痕之间必须呈等间距,且为直线行排列。选用了HV-120型维氏硬度计进行试验,用两块方形磁铁起到固定试样的作用;同时,还要用游标卡尺的精度来保证压痕之间的距离准确。其操作方法简单易行,达到了试样成直线平稳移动的效果,使压痕的间距尺寸误差为±0．02mm。定位准确,硬度压痕的对角线清晰,数值可靠,符合规程的要求。     

工艺参数对激光冲击微造型效果的影响

激光表面织构(LST)是一种广泛应用的表面微造型方法,然而其主要缺点是消融过程会导致材料熔化、断裂以及改变表面微观组织。基于激光冲击强化(LSP)技术在Al7075表面开展微凹坑造型研究,其特点是既能克服激光表面织构的缺点,又能继承激光冲击强化的优点。使用AxioCSM700真彩色共聚焦扫描显微镜和VeccoWYKO表面形貌仪观察微凹坑的几何形貌,用HXD-1000TMSC/LCD MH-VK双压头显微硬度计测量微凹坑的内部以及周围表面的硬度。实验结果表明,微凹坑的直径和深度随激光的脉冲能量、冲击次数、离焦量、约束层K9玻璃厚度的变化呈现一定的变化规律;微凹坑的影响区域,沿着凹坑径向方向硬度逐渐增加,中心位置硬度最大,这有利于提高材料的抗磨损能力。     

Analysis of Pipes Containing Plain and Gouged Dents

Abstract: The paper discusses numerical results obtained for pipes subjected to transverse denting by a rigid indenter. Dents produced by different shapes of indenters are assessed for the amount of cross‐sectional distortion of the pipe and for propagation of this distortion along the length of the pipe. The contact area between the rigid indenter and the deformable pipe, as well as between the pipe and the rigid support is calculated for different loading configurations and for different shapes of indenters. Pipe supports considered include elastic springs, a rigid saddle and a rigid plate. In numerical work, axial cracks and gouges of different sizes have been introduced to the pipe's outer surface. Damaged pipes are then subjected to denting and results, including denting forces, distortion of the cross‐sectional area and limit loads are compared with the corresponding results obtained for non‐dented and non‐gouged geometries as well as with non‐dented but gouged cases. Finally, selected numerical results are compared to experimental data in order to demonstrate the adequacy of the adopted modelling and analysis approach.     

异形筘片模具的刃磨

说明了异形筘片模具刃磨的重要性，应在生产中正确选用设备、砂轮及磨削规范，以便保证模具的精度和寿命。     

Collapse of pipes with plain or gouged dents by bending moment

This paper discusses collapse caused by the bending moment of mild steel pipes containing plain or gouged dents.     

宝钢电镀锌汽车板生产技术的最新进展

2003年,宝钢在解决厚镀锌层汽车外板生产的关键技术方面获得突破性进展:即提出了控制导电辊粘锌的有效措施;掌握了控制预磷化板磷化膜质量的诀窍;解决了边部枝晶问题,使得宝钢具备了稳定大批量生产O5板的能力以及与国外钢铁列强角逐高档电镀锌O5板市场的实力.     

FR-4覆铜板外观质量改进与提高

该文主要介绍了影响FR-4覆铜板外观质量的原因,并提出一些改进方法。     

高纵向应变下管道凹坑的评价方法

管道施工建设和服役期间发生的外部干扰经常会导致管道产生凹坑,在地面运动和地震活动区域,管道也会产生高纵向应变。在假定主要载荷为内压且纵向应变水平较低的情况下,开发并验证了目前的凹坑评价方法,凹坑在高纵向应变下的行为尚不清楚。讨论了由美国DOT（美国交通运输部）和PHMSA（美国管道与危险材料安全管理局）资助的关于高纵向应变下凹坑评价准则。通过参数数值分析,确定并研究了带凹坑管道中,控制压缩应变能力（CSC）的关键参数和原理。通过参数分析和全尺寸验证试验,制定了高纵向应变条件下带凹坑钢管的CSC评价方法。     

Strength assessment of steel plates subjected to compressive load and dent deformation

This work presents an assessment of the ultimate compressive strength of damaged steel plates with a local dent. Extensive non-linear finite element analyses are performed, where three groups of analyses are considered. In the first group, the effect of the dent orientation (longitudinal and transverse) is studied for three plate thicknesses. For the second group, the direction of the dent depth (upward and downward) with respect to the global initial imperfection is explored. In the third group, the variation of the dent size for several plate thicknesses and its influence on ultimate compressive strength is investigated. The post-collapse behaviours are discussed and the inflection plate slenderness with and without dent is observed, at which the behaviour of the plate changed. A certain dent breadth to the plate breadth ratio is established, revealing the different plate response. Based on the performed analyses, a generalised expression of the ultimate strength reduction factor due to dent is developed.