基于虚拟仪器技术的多功能摩擦磨损试验机的研制

摩擦磨损试验机是摩擦学研究必不可少的重要试验工具,但目前大多摩擦磨损试验机功能简单、工况参数不可控或可控性不好。阐述多功能摩擦磨损试验机的研制和其主要功能特点。试验机采用交流伺服技术直接驱动,速度闭环可控;静载荷通过压缩加载弹簧实现,使用可控激振器进行动载荷加载,加载操作简单易控;由润滑油泵控制润滑液的添加。这些参数由计算机实现自动控制,能很好地模拟实际工况。测控系统软件在虚拟仪器技术基础上采用Lab-VIEW平台开发,实现对数据的自动实时采集、处理和结果显示等功能。试验证明该试验机能很好地模拟实际工况,满足多种摩擦学研究需要。     

义齿材料摩擦磨损试验机及控制系统设计

根据义齿摩擦磨损试验环境标准开发设计了温度和湿度可控制的往复式摩擦磨损试验机.该试验机采用曲柄导杆滑块机构实现往复运动,使用球一盘接触方式进行试件摩擦磨损,利用半导体应变片对摩擦过程中摩擦系数进行动态跟踪测试,通过调整砝码实现正压力的改变,通过改变偏心轮的偏心距实现往复行程变化.该试验机不但可对义齿材料进行摩擦磨损试验,还可对金属及其他非金属材料进行摩擦磨损试验.     

冲击-滑动工况条件下套管磨损机制图像分析

为实验验证套管磨损机制的理论研究,在冲击-滑动工况条件下进行了套管磨损的试验研究。运用SK2005工业显微镜、铁谱显微镜和扫描电镜,对套管磨损试验后的磨擦磨损表面进行了显微图像分析。研究发现在冲击-滑动工况条件下,深井超深井套管磨损机制主要为接触疲劳磨损、粘着磨损和磨粒磨损,从试验角度验证了深井超深井套管磨损的主要原因是钻杆对套管的横向冲击。     

基于UHMWPE基复合材料摩擦性能研究试验机的设计

基于UHMWPE基复合材料在特殊条件下摩擦磨损性能设计了一台摩擦磨损试验机.试验机主要包括电气控制、数据采集和机械装置3部分.系统结构紧凑,操作方便,克服了传统摩擦磨损试验机体积大、质量大、成本高、试件结构尺寸单一的缺点,同时可研究UHMWPE基复合材料在摩擦条件下的温度场变化规律.摩擦试验结果表明:试验机运转稳定,数据检测方便.     

磨损间隙调整式环块摩擦试验机的研制

为了优选橡胶材料和掌握其摩擦磨损机制,以提高橡胶衬套材料的耐磨性和液体介质输送设备的使用寿命,研制一台磨损间隙调整式环块摩擦试验机。该试验机可通过加载机构可实现对橡胶试块的垂直加载或橡胶试块与摩擦环之间的间隙调整,并可实现干摩擦和含固体颗粒黏稠液体介质润滑下金属摩擦环与橡胶之间的摩擦磨损试验。利用该试验机对丁腈橡胶在不同磨损间隙下的摩擦磨损性能进行测试。试验结果表明,该试验机在过盈配合及不同磨损间隙下均具有较高的试验精度。     

基于人工神经网络技术的环块试验机智能测控系统

针对目前大多数摩擦磨损试验机环境因素不可控、线速度不能实时优化调控的缺点,利用虚拟仪器开发平台LabVIEW开发一种基于人工神经网络技术的摩擦磨损试验机智能测控系统。该智能测控系统以工控机为核心,集数据采集、数据处理和实验环境控制为一体,既可实现温度、载荷、摩擦力、线速度和摩擦因数等参数的实时检测,又能对线速度进行实时调控。该试验机可更好地模拟现实工况条件,可开展多种环境因素的摩擦学实验研究。     

钻杆接头材料35CrMo钢硫氮共渗层的摩擦学性能

为了提高钻杆接头的使用寿命,利用离子渗氮和硫氮共渗技术在钻杆接头材料35CrMo钢表面制备了氮化层和硫氮共渗层。在油润滑条件下采用自制的球-盘磨损试验机考察了表面渗层的摩擦磨损性能。利用了XRD研究了表面层的相结构,采用了带EDS的SEM对表面改性层和磨损表面进行了分析。结果表明:35CrMo钢硫氮共渗层的摩擦学性能明显优于原始渗氮层;具有优良润滑作用的FeS固体润滑膜在高硬度氮化层的支撑下,可以有效地改善钻杆接头的摩擦磨损性能。     

钛合金TC4与铝青铜在冲击滑动耦合作用下的磨损特性

采用正交试验方法,利用冲击滑动磨损试验装置研究钛合金TC4与铝青铜在冲击滑动耦合作用下的磨损特性,运用极差分析处理试验数据,研究试验因素对冲击试件(铝青铜)平均磨损体积,回转试件(钛合金)平均磨损体积及两者比值的影响.结果表明:较硬的钛合金的磨损体积大于较软的铝青铜.对磨痕表面形貌分析表明,冲击频率增大,冲击试件(铝青铜)的磨损形式呈现由机械作用到黏着剥落的变化;回转试件(钛合金) 磨痕表面呈片状剥落,随滑动速度的增加,片状剥落趋向严重;冲击试件与回转试件之间存在物质转移,主要为钛合金向铝青铜转移.     

桩基础施工新技术专题讲座(二十三) 气动潜孔锤与长螺旋钻孔机组合技术(上)

气动潜孔锤长螺旋钻孔灌注桩成孔原理该成孔原理属于气动潜孔锤同步跟管成孔施工技术,利用双动力头分别驱动钻杆和设在钻杆底部的气动潜孔锤及外部钢套管。钻杆动力头带动长螺旋钻杆及底部潜孔锤作顺时针转动,潜孔锤在压缩空气作用下所产生的冲击功和冲击频率直接传给锤头快速破碎孔内岩石;同时套管动力头驱动钢套管逆时针旋转,钢套管下端环状合金钻头切割岩层与潜孔锤同步跟进成孔;穿管过程中形成的渣土和岩石颗粒借助于潜孔锤排出的压缩空气从钢套管与螺旋杆之间向上吹起排出套管外,从而实现孔底冲击回转钻进与清孔同步施工。     

钻杆内壁腐蚀的交直流复合磁化漏磁检测方法

钻杆长期服役后内壁出现的腐蚀是造成钻杆断裂的主要原因,针对钻杆内壁腐蚀的检测,提出了一种基于复合磁化的漏磁检测方法。该方法通过阵列感应线圈拾取钻杆外壁交流磁场的变化,进而评价内壁腐蚀产生的壁厚减薄状态,规避了强背景磁场下用霍尔元件测量磁场时量程范围不足、灵敏度不够等问题。利用有限元仿真软件分析壁厚减薄上方的相对磁导率分布,对比了有、无壁厚减薄的磁感应强度变化率,仿真与实验结果表明该方法可以实现钻杆内壁壁厚减薄的检测。     

一种新型套管磨损表面形貌检测装置的研制及应用

介绍了一种自行研制的套管表面形貌检测仪的结构、工作原理。以S135钻杆和P110套管为摩擦副,以不同的钻井液（清水和不同成分的泥浆）为中间介质,在套管磨损实验机上进行了磨损实验,采用研制的套管表面形貌检测仪测试了摩擦副磨损表面形貌。测试结果表明,自行设计的套管表面磨损检测仪可检测套管磨损表面形貌,并可用于计算表面形貌参数。结合磨损条件,该检测仪可以分析套管的摩擦磨损性能。     

基于不同冲击频率条件下的套管磨损表面分形特征及磨损机制研究

选取TP140套管在自行研制的套管磨损试验机上进行磨损试验,利用表面形貌仪测量在不同冲击频率条件下的套管表面磨损形貌,选用结构函数法考察磨损形貌的分形特征,使用拟合误差法确定分形曲线的无标度区间并计算分形维数,利用扫描电子显微镜分析其磨损机制。结果表明:在不同冲击频率条件下的套管表面形貌存在明显的分形特征,但分形维数会随频率的不同而有所变化。从光学图像和扫描电镜图像可以看出磨损机制主要有粘着磨损和犁沟。     

Dry sliding friction and casing wear behavior of PCD reinforced WC matrix composites

The friction and casing wear properties of PCD reinforced WC matrix composites were investigated using a cylinder-on-ring wear-testing machine against N80 casing steel counterface under dry sliding conditions. The results indicate that the friction and casing wear rate of PCD reinforced WC matrix composites are the lowest among the materials. As the applied load and sliding speed steadily increase, the friction coefficients of PCD reinforced WC matrix composites decrease. In addition, the casing wear rates increase with increasing load, but decline with sliding velocity. The dominant wear mechanism of the PCD composite is the micro-cutting wear, accompanied by adhesive wear.     

Analysis on collapse strength of casing wear

Carrying capacity of the casing will reduce after the casing is worn, which seriously affects the subsequent well drilling, well completion, oil extraction and well repair. A lot of researches on calculation of casing wear collapse strength have been done, but few of them focus on collapsing failure mechanism, and influencing factors and law of collapse strength. So, significant difference between estimated value and actual value of collapse strength comes into being. By theoretical analysis, numerical simulation and actual test, the collapsing failure mechanism of casing wear as well as the influencing factors and laws of collapse strength are investigated, and the investigation results show that collapse of crescent casing wear belongs to "three hinged" instability. The severely-worn position on the casing is yielded into the plastic zone first then deformed greatly, which causes the plastic instability of the whole structure. The casing wear collapse strength presents changes of exponent, power function and linear trend with the residual casing wall thickness, wear radius and axial load, respectively. When the flexibility is less than 10°/30 m, the borehole bending has less impact on casing collapse strength. Thus, the computation model for the casing wear collapsing strength is established by introducing wear radius coefficient and casing equivalent yield strength, at the same time, the model is tested. The test results show that the relative error for the computation model is less than 5%. The research results provide a basis for design of the casing string strength and evaluation of down-hole safety.     

钻井液用植物油润滑剂的制备及摩擦学性能研究

为了使钻井液用植物油润滑剂在高压和高温氧化后仍具有良好的抗磨减摩性能,将层状固体润滑剂石墨、蛇纹石加入植物油中,合成了几种含固体润滑剂的钻井液用植物油润滑剂;利用UMT-2球盘式摩擦试验机考察了各润滑剂的摩擦性能;在摇臂钻床上模拟钻探的摩擦工况,考察了合成的润滑剂的抗磨性能,利用扫描电子显微镜观察了钻头的磨损形貌。结果表明,在植物油中添加石墨、蛇纹石可以降低植物油的摩擦因数和摩擦副的磨损,同时可使植物油在高温氧化后仍能保持良好的减摩抗磨性能。     

O-ring wear test machine

An abrasive wear test machine was built to study the friction and wear resistance of O-ring materials. In this test machine, two O-ring segments are held against a rotating roughened metal disc. The disc and the O-ring specimens are submerged in an abrasive fluid (drilling mud). The roughened disc surface draws the abrasive particles between the O-ring and the disc surface to produce three-body abrasive wear. Wear occurs on both the specimen and the disc. The wear of the O-ring specimen is determined by weight loss measurements. By careful design of the disc and selection of the test conditions, wear surface similarity was obtained between machine-tested O-rings and O-rings used in field-operated equipment. The testing machine is described, preliminary wear results are presented and photographs of field-worn and machine-worn specimens are shown for three materials.     

Notes for contributors

The load carrying capacity of a tribological system can be increased by superposition of a dynamic load to a statically applied load. In this note an example of a test result with a pin-on-disk machine is shown which demonstrates the changes of different characteristic parameters (friction coefficient, pin temperature, contact resistance and wear rate) as a result of the induced vibrations.     

Numerical simulation of concrete pumping process and investigation of wear mechanism of the piping wall

A numerical simulation has been conducted to study the solid-fluid multi-phase flow problem in concrete pumping process. The kinematics and trajectory of the discrete particles as well as the particle-particle interaction were predicted by DEM while the motion of the continuous fluid phase was evaluated by a Navier-Stokes solver, and a pressure gradient force model was adopted to calculate the solid-fluid interaction force. A case of pneumatic conveying was utilized to demonstrate the capability of the coupling model. The concrete pumping process was then simulated, where several flow features were observed such as roping, particle segregation and particle concentration. The frequency of the particles impacting on the bended pipe was monitored, a new time average collision intensity model based on impact force has been proposed to investigate the wear mechanism of the elbow. The location of maximum erosive wear damage in the elbow was predicted. Statistical results were in good agreement with that observed in actual pumping process. It is found that the present multi-phase coupling model can predict the wear behavior of the bended pipe accurately, and consequently provide an effective guidance for the design of concrete pumping pipe.