基于数值仿真技术求解铰链机构磨损概率寿命

以数值仿真技术对曲柄滑块机构中的铰链摩擦副磨损状态进行了研究,建立了同时考虑压力和温度影响时铰链机构的磨损仿真模型,对3对铰链接触处的磨损提出了具体的算法方案,在Visual Basic环境下编写了通用程序获得了更加准确的仿真结果。首次提出了磨损概率寿命的概念,在载荷呈正态随机分布时利用蒙特卡洛法计算出3对铰链摩擦副的磨损概率寿命。     

基于数值仿真技术求解铰链机构磨损概率寿命

基于离散数学理论和计算机技术,用数值仿真方法,以曲柄滑块机构中的铰链摩擦副磨损状态为研究对象,针对光面磨损失效形式,建立同时考虑压力和温度影响时铰链机构的磨损数值仿真模型,提出具体的算法方案并编写了通用程序.引入位置矢量和磨损步长的概念,使连续的磨损过程离散化,并对铰链机构的运动规律做了动态跟踪.提出磨损概率寿命的概念,利用蒙特卡洛法,通过算例实现对铰链机构磨损概率寿命的可靠性计算,解决了零件磨损寿命的可靠性预测问题.结果表明:复杂的磨损过程可用数值法进行模拟仿真,从而摆脱传统的仅依赖试验的研究方法,通过一系列离散性准静态模型解决经典微积分数学方法无法解决的动态和非线性磨损问题,具有良好的工程应用前景.     

某型通风隔离阀传动机构铰链副磨损可靠性分析

通风隔离阀传动机构铰链副的磨损可靠性对其运动功能的精确实现至关重要,文中提出了一种较为精确的计算其传动机构铰链副磨损可靠度的方法,首先基于应力-强度干涉模型建立铰链副磨损可靠性分析模型,然后将铰链副间隙误差看作随机变量,分别确定了许用磨损量和实际磨损量的分布情况,最后计算了磨损可靠度,为制定传动机构设计和使用维护方案提供了科学合理的建议。在确定铰链副实际磨损量的分布情况时,基于Archard磨损理论,建立了新的铰链副磨损量计算模型,通过动态仿真分析,测量并拟合获得运动和受力变化规律,并基于蒙特卡罗原理较为精确地模拟磨损量的分布,使之更加贴近实际。     

平面四杆机构的可靠性分析

将诸原始误差均视为随机变量，对平面四杆机构具有杆长尺寸误差、铰链间隙误差及磨损量等各项随机变量分别进行了分析；应用微小位移的线性叠加原理综合出各项误差导致的机构运动输出总误差，建立了机构运动精度可靠性分析模型；利用计算机数字仿真技术，考察了机构中杆长尺寸误差和铰链间隙(或磨损)误差随机变量均值和方差的改变，对机构输出运动精度可靠度的影响，从中获得了一些有意义的结论。     

多因素耦合下机构运动精度可靠性仿真试验及寿命评估

针对影响平面机构运动精度因素较多且不能忽视的问题,将影响机构运动精度可靠性因素分为非累积性因素和累积性因素,提出了非累积性因素和累积性因素耦合作用下平面机构的运动精度可靠性仿真试验方法;根据可靠性仿真试验得出了累积性因素中机构允许的最大磨损量,利用Archard磨损模型分析铰链的磨损速率,然后基于最大允许磨损量和磨损速率建立了概率可靠性寿命评估模型和模糊可靠性寿命评估模型,根据该模型分别对机构进行寿命评估,并进行了对比。以曲柄滑块机构为例进行分析,得到了该机构不同铰链间隙下运动精度可靠度以及该机构的可靠性寿命,验证了方法的可行性。     

磨损对曲柄压力机滑块机构运动可靠性的影响

以典型磨损规律，可靠性工程理论以及概率工程设计方法对曲柄压力机的滑块机构运动参数精度进行了分析研究，全面反映了滑块机构铰链连接处的磨损对曲柄压力机运动可靠性的影响。     

基于SimMechanics的平面铰链四杆机构控制系统计算机仿真

使用SimMechanics建立了平面铰链四杆机构的仿真模型。这一模型从控制系统研究出发，适合通过改变机构参数和系统输入，对含有平面铰链四杆机构的机电控制系统进行仿真研究。仿真结果表明所建的模型符合实际情况，是正确的。     

平面连杆机构运动精度可靠性及灵敏度分析

针对平面连杆机构传动路线长,存在较大的积累误差,对机构的运动精度产生的影响不容忽视的问题,提出了加工误差、结构变形、装配间隙及铰链磨损多因素耦合作用下运动机构精度可靠性分析的建模方法及求解流程。用动量交换法建立铰链间隙的碰撞模型后对机构进行动力学分析,基于动力学分析结果,利用胡克定律及有限元法分析部件变形,利用Archard磨损模型分析铰链的磨损量。在此基础上,给出了加工误差与部件变形影响下杆长的分布参数以及装配间隙与铰链磨损影响下铰链间隙的分布参数,然后将铰链间隙用无质量连杆模型替换,建立并求解机构的运动方程。通过对飞机舱门收放机构的算例分析,得到了该机构在不同收放次数下的运动精度可靠度及对应的可靠性灵敏度,并给出了制造维护建议,证明了方法的可行性。     

一种烤箱自平衡门铰链机构的设计与分析

介绍了一种烤箱自平衡门铰链机构的设计。为解决烤箱柜门打开后不能在任意角度停顿的问题，首先研究了烤箱柜门的平衡方法，在此基础上设计了一种铰链的平衡机构，并利用ADAMS软件对机构进行动力学仿真分析，验证了铰链平衡原理的可行性。铰链实现了柜门在开门后任意角度停顿，同时考虑了柜门密封性与可拆卸的问题，使装配有该铰链的烤箱品质得到了较大提升。     

基于铰链磨损的机构可靠性研究与应用

研究了基于铰链磨损的机构可靠性，分析了可靠性研究的原理和方法，并通过实例说明其应用。     

A generalized analytical compliance model for transversely symmetric three-segment flexure hinges

This paper presents a generalized compliance model for a three-segment notch flexure hinge with transverse symmetry. This flexure hinge configuration is most frequently employed in planar-motion, small-displacement compliant mechanisms. The axial and bending compliances are derived for this flexure hinge based on the compliances of two flexure components. The derivation is generalized such that it can be applied to various segment geometries. Using this open-ended model, a three-segment right elliptical corner-filleted flexure hinge design was analyzed. This geometric configuration introduces additional geometric parameters, which can be used to optimize the compliance of the flexure hinge without modifying its gross dimensions. The results of the analysis were validated in part by modifying the geometric parameters of the center segment and elliptical corner fillets to form limiting cases corresponding to several previously investigated configurations, namely right elliptical, three-segment right circular corner-filleted, and right circular geometries. Finite element analysis simulation and experimental testing were used to further validate the three-segment right elliptical corner-filleted analytical model. Additional simulations based on the analytical model were performed to highlight the influence of geometric parameters on compliances and to investigate shear effects for short flexure hinges.     

平面凸轮机构运动精度可靠性分析与数字仿真

运用微小位移的线性叠加原理,将平面凸轮类机构的凸轮与滚子的形状误差、铰链与移动副的间隙(包括磨损的影响)、凸轮及滚子的偏心、凸轮偏距圆尺寸误差等作为随机变量,建立了机构运动精度可靠性分析模型;利用计算机数字仿真技术,考察了机构各项误差导致的机构运动输出总误差对机构输出运动精度可靠度的影响,从中获得了一些有意义的结论。     

双曲线弹性铰链的特性分析

为了得到一个结构紧凑、无摩擦、无磨损且高效率的微进给装置，分析了双曲线凹槽弹性铰链的特性，得到其在不同载荷作用下刚度的解析解，此外，还利用有限元的方法对弹性铰链的刚度和运动精度进行了校验。     

Predictive role of the lambda ratio in the evaluation of metal-on-metal total hip replacement

The wear of metal-on-metal bearings is affected by various design parameters, such as the clearance or surface roughness. It would be very useful to have a significant indicator of wear according to these design parameters, such as the lambda ratio. Three different batches of cast high- and low-carbon cobalt-chromium hip implants (28 mm, 32 mm, and 36 mm diameters) were tested in a hip joint simulator for 2 x 10(6) cycles. Bovine calf serum was used as lubricant, and the samples were weighed at regular intervals during the test. The predictive role of the lambda ratio on the wear behaviour was investigated. Three different configurations were tested to explore the wear rate for a broad range of lambda ratios. The results of these studies clearly showed that the femoral heads of 36 mm diameter had the best wear behaviour with respect to the other two smaller configurations tested. From a predictive point of view, the lambda ratios associated with the configurations tested could clearly indicate that the femoral heads of 36 mm diameter worked in the mixed-lubrication regime (lambda > 1); all the smallest configurations (28mm size) had lambda < 1, thus showing their aptitude to work in the boundary lubrication regime, with substantially higher volume depletion due to wear. The lambda values associated with the 32 mm size varied in a range around 1 (0.95 < lambda < 1.16), suggesting the possibility of operating in the mixed-lubrication regime.     

高分子复合材料齿轮磨损模型及磨损测试研究

基于Archard磨损模型,建立高分子复合材料齿轮磨损量模型;分析黏弹性体高分子复合材料齿轮的啮合特性,探讨高分子复合材料齿轮磨损量测量原理。设计了一种高分子复合材料齿轮磨损量测量系统,该系统的测试原理是,通过单铰链支撑的悬臂梁和枢轴箱对齿轮动态加载,使齿轮轮齿表面发生磨损从而导致枢轴箱发生旋转,通过位移传感器测量枢轴箱的偏转角,然后由建立的偏转角与齿轮磨损量之间的关系模型计算得到磨损量。在设计的测试系统上对尼龙66齿轮进行疲劳磨损实验,实验结果和理论模型计算结果基本吻合,既验证了理论模型的正确性,也为高分子复合材料齿轮磨损测试提供了一种新方法。     

An integrated methodology for predicting material wear rates due to erosion

Erosion–corrosion damage within pipelines and associated fluid handling equipment is prevalent in the oil and gas sector and other process industries where solid-laden flows, such as those involved in the processing of oil sands are found. As a first step towards trying to understand the interactions between erosion and corrosion it is important to understand the erosion damage that occurs as a result of solid particle impact on a surface (usually metal). This paper addresses this in relation to transport of fluids in the oil-sands industry. A method for predicting erosion damage has been developed, using a combination of standard laboratory based experiments and Computational Fluid Dynamic (CFD) simulations. This paper provides validation of such an approach: (i) a universal wear map is generated for the material in question using a jet impingement test (JIT) to generate a wear scar. The local wear rate from this is interpreted using a CFD simulation of the test to generate a map giving local wear as a function of particle impact velocity and angle; (ii) a CFD solution is calculated for a series of different erosion configurations giving the particle impact data at each point on the surface. The wear map from the first stage is then used to give the local wear rate. The power of this method is that once a material-specific map has been generated then wear on any geometry can be calculated through the simulation of flow using CFD.     

The wear of martensitic stainless steel against tungsten carbide at temperatures up to 500 °C

The bearings in air motors of modern jet aircraft engines must operate dry in hostile conditions at temperatures up to 500 °C. One of the few metallurgical combinations which can function efficiently under these conditions is martensitic stainless steel on tungsten carbide. The work described was initiated to isolate the wear mechanism of such steels in contact with tungsten carbide at elevated temperatures. Experiments were carried out for pure sliding conditions (pin-on-disk experiments) and for rolling-sliding angular-contact bearings such as those used in practice. Wear rates were measured for both configurations for a series of loads, speeds and surface temperatures and extensive X-ray diffraction analyses were carried out on wear debris and on worn surfaces. Three distinct mechanisms of wear were established and found to be present in both configurations. These involve oxidation and abrasive wear at lower temperatures but become heavily dependent on material transfer as temperature increases. It is proposed from the results that the pin-on-disk experiments may be useful as a screening test for the selection of materials without the considerable cost of producing one-off angular-contact components. More evidence from other materials is, however, necessary to establish the validity of the test.