固铍处理几种工艺方法讨论

近年来,贵溪冶炼厂贫化电炉渣含铜呈逐年上升趋势,究其原因较多,其中在贫化电炉中处理固铍是主要原因之一.文章主要是时贵溪冶炼厂固铍处理生产现状进行介绍,对贵冶固铍处理的几种可能方法进行分析和讨论,并进行相应的技术经济比较.     

液压夹轨装置夹不紧原因分析及夹轨装置的改造

本文通过对液压夹轨装置结构和机理分析，指出原设计夹轨装置预留压紧量(Smax-S)不足是导致夹轨装置锁不紧的主要原因，并对相应间隙和零件进行了调整和改造，解决了拖车的锁紧问题。     

浅议数控车床刀架定位法

利用数控车床具有的精确定位能力和刀架的限位作用,实现工件装夹过程中的准确定位,即为刀架定位法。较之传统定位方法,刀架定位法具有定位精度高、适用于不同尺寸的工件,且操作方便、可靠、实用的优点,值得在数控加工生产中优先采用。     

全电压关合试验中的控制策略及实现

对10kV架空绝缘线路的短路电流沿线分布和短路故障切除时间以及雷击闪络概率进行了计算和分析，提出了线路用防弧金具和放电箝位绝缘子的工频电弧试验条件：①工频电弧试验用的短路电流有效值和持续时间分为两挡：有效值取20kA，持续时间为0．1s和有效值取10kA，持续时间为0．5s。②工频电弧试验短路次数取5次比较合适。③绝缘导线和试品应按实际情况布置，水泥电杆高度大于2．0m等。     

Modeling and analysis of workpiece stability based on the linear programming method

After being located on a machine bed, a workpiece will be subject to gravity and cutting forces during the machining operation. In order to keep the locating precision as well as the production safety, it is necessary to maintain the workpiece stability. In this paper, a linear programming method is proposed for stability analysis of the workpiece. Based on the linear approximation of the friction cone, a quantitative criterion is established to verify the workpiece stability in association with the rationality of the clamping sequence, magnitude of clamping forces and clamping placement. This criterion allows designers to plan reasonably the clamping sequence, magnitude of clamping forces as well as clamping placement. Compared with existing methods, the main advantage of this approach lies in that the sophisticated computing of contact forces between fixture elements and the workpiece is avoided. In this work, both friction and frictionless cases can be easily taken into account in stability analysis. Mathematical formulations of the method are given and some numerical tests are finally demonstrated to validate the proposed method.     

Influence of the gasket materials on the clamping pressure distribution in a PEM water electrolyzer: Bolt torques and operation mode in pre-conditioning

To keep optimally connected, all electrolysis cell elements is one of the most important design criteria. The optimal distribution of the clamping points is crucial to increasing cell performance. In this work, the compression pressure distribution inside of a 25 cm² PEM electrolysis cell was evaluated, using different materials: Teflon®, Viton®, ethylene propylene diene monomer rubber (EPDM), and nitrile rubber. Sealing material evaluation was performed taking as performance indicators: total compressed area (%) and compression pressure, for different torques applied. Pressure distribution was obtained by using pressure-sensitive films, analyzing the distribution of pressure points from three-dimensional plots (3D), and quantifying intensities of the images obtained. Results showed that pressure points distribution depends on the stiffness and thickness of the gasket materials. For a tightening torque of 3.70 N m, a pressure of 2.23 MPa is obtained with 85% of the membrane area compressed using nitrile rubber-EPDM gaskets.     

Prediction of fatigue life in aircraft double lap bolted joints using several multiaxial fatigue criteria

In this research, the effects of torque tightening on the fatigue strength of 2024-T3 aluminium alloy double lap bolted joints have been studied via experimental and multiaxial fatigue analysis. To do so, three sets of the specimens were prepared and each subjected to different levels of torque i.e. 1, 2.5 and 5 N m and then fatigue tests were carried out at various cyclic longitudinal load levels. A non-linear finite element ANSYS code was used to obtain stress and strain distribution in the joint plates due to torque tightening of bolt and longitudinal applied loads. Fatigue lives of the specimens were estimated with six different multiaxial fatigue criteria by means of local stress and strain distribution obtained from finite element analysis. Multiaxial fatigue analysis and experimental results revealed that the fatigue life of double lap bolted joints were improved by increasing the clamping force due to compressive stresses which appeared around the hole.     

机械增力丝杠增力机构的有限元仿真

对机械增力丝杠增力机构的增力原理进行了分析,并通过有限元仿真指出了楔形块是增力机构中最为薄弱的环节,有限元分析结果表明,合理设计增力机构,首先要考虑楔形块的载荷承受能力,其次要考虑斜块与楔形块接触面的承载能力.     

基于电机电流检测的汽车电动车窗纹波防夹系统设计

为了有效地解决汽车电动车窗夹伤乘员的安全问题,提出了一种新的汽车电动车窗防夹系统——基于电机电流检测的纹波防夹系统。在硬件设计中,以S9S12ZCL32为核心,设计了电机电流采集及其处理方法;在软件设计中,验证了电机电流与外界阻力的关系,提出了利用电流积分的方法判断夹持力大小,并实现防夹功能。经过多次实验,结果证明了该方法的可行性和系统的稳定性。     

液压锁紧轴套锁紧扭矩计算与实验研究

液压锁紧轴套是五轴联动机床的关键部件,能够在压力载荷作用下发生较大的弹性变形,锁紧进给轴的转动自由度,对机床定位锁紧和加工精度有重要的影响,锁紧扭矩是液压锁紧轴套设计的重要参数。为研究轴套壁厚、压力载荷、配合间隙及轴套长度4个参数对液压锁紧轴套锁紧进给轴时产生的锁紧扭矩影响,首先用有限元方法计算了液压锁紧轴套工作时的变形、轴套与进给轴之间的接触应力分布;然后在进给轴外表面对接触压力积分得到轴套作用在进给轴上的正压力,进而得到锁紧扭矩;最后在自主设计的实验台上进行锁紧扭矩测试实验,对有限元方法计算数据进行验证。结果表明:有限元方法计算得到的理论数据相对实验数据相对偏差均小于4.87%,验证了有限元方法计算的理论数据可靠性。该有限元方法计算的理论数据可以对液压锁紧轴套结构设计提供参考。