基于人工神经网络的齿轮胶合承载能力及其可靠度计算方法研究

本文将人工神经网络用于传动齿轮胶合承载能力及其可靠度计算，为探索人工神经网络在机械设计中的应用进行了有益的尝试，将该方法用于某履带车辆行星变速装置行星排外啮合传动齿轮的胶合承载能力及其可靠度计算，并和常规方法比较，说明该方法是正确可行的。     

基于最小油膜厚度的齿轮胶合强度模糊可靠度仿真

在用弹流润滑理论计算齿间最小油膜厚度方法的基础上,分析和讨论了齿轮传动中齿面胶合失效的模糊性,将计算机仿真技术应用于机械模糊性分析中,建立了齿轮胶合强度的模糊可靠度仿真模型,并举例说明了仿真的一般方法.实践证明:相比其他可靠度计算方法,模糊可靠度仿真计算具有更大的适应性和灵活性.     

渐开线圆柱齿轮抗胶合可靠性计算

本文在油膜厚度法的基础上对圆周速度小于４ｍ／ｓ的渐开线圆柱齿轮进行抗胶合可靠性分析和计算，能在给定抗胶合可靠度的情况下，确定啮合齿面的粗糙度Ｒａ１、Ｒａ２或在已知Ｒａ１、Ｒａ２的条件下，估算齿轮的抗胶合可靠度。     

基于闪温法的传动齿轮抗胶合可靠度分析与计算

以Block闪温法为基础，论述了齿轮传动抗胶合可靠性分析模型和计算方法，并用实例加以说明，为探索可靠性技术在齿轮抗胶合承载能力计算中的应用进行了有益的尝试。     

渐开线圆柱齿轮抗胶合可靠性计算

本文在油膜厚度法的基础上对圆周速度小于4m/s的渐开线圆柱齿轮进行抗胶合可靠性分析和计算。能在给定抗胶合可靠度的情况下,确定啮合齿面的粗糙度R_(a1)、R_(a2),或在已知R_(a1)、R_(a2)的条件下,估算齿轮的抗胶合可靠度。     

多模式失效的机械零件可靠度计算新理论

解决了长期未能解决的机械零件多模式相关的可靠度定量计算难题,提出了多模失效的机械零件可靠度值在独立假设理论计算值和薄弱环节理论计算值之间,而且是一个连续过程,随主次失效模式相关系数ρ12呈线性变化,给出了可靠度计算数学模型,并采用O.Ditlevsen理论给出了科学严谨的理论证明,同时给出了传动轴可靠度算例。     

模糊可靠度的区间估计方法

对模糊可靠度进行了分类，建立了三种常见类型模糊可靠度区间估计的计算模型，给出了模糊可靠度置信区间的确定方法。实例分析表明了模糊可靠度区间估计的实用价值。     

边界摩擦和磨损零件的可靠性设计方法

针对处于边界摩擦和干摩擦状态下工作的许多机械零件——铰链、导轨、汽缸和活塞、凸轮、滑动轴承、离合器等的主要失效方式为胶合与磨损,提出防止剧烈磨损、抗胶合和耐磨等三种可靠性设计方法。解决了面大量广的潜水泵推力轴承的可靠性耐磨设计问题。提出的磨损率计算的工程数学模型和可靠性磨损设计法,能用计算方法来预测磨损寿命和磨损量。     

实用V带传动系统可靠度计算

利用可靠性设计原理，在常规设计基础上，借助于变差系数，介绍了V带传动的可靠度计算方法，并给出了V带传动可靠度计算实例。     

机构的运动误差分析与可靠性计算

在分析机构运动误差的基础上，讨论了机构运动可靠度的计算方法，包括一次二阶矩法与蒙特卡罗模拟方法；提出了一种以蒙特卡罗法与数值解法相结合求解机构运动可靠度的混合计算法；给出了一个作为传动构的四杆机构运动可靠度计算的实例。     

齿轮胶合强度设计计算方法的研究

本文根据作者多年来在齿轮胶合理论与计算方面的研究成果,首次提出了齿轮第三个计算理论体系——新的齿轮胶合强度计算方法。文中给出了校核公式、理论设计计算公式和对比计算公式。     

齿轮抗胶合的最佳变位系数经验计算法

本文以齿面积分温度准则为出发点,通过计算程序用数值积分方法对齿面的平均闪温进行了优化计算,获得了大量在常用范围内适用的抗胶合最佳变位系数组合,再经回归分析,建立了适合工程实用的抗胶合的最佳变位系数经验计算公式。通过试验验证,表明该公式具有较好的可靠性和实用性,而且使用简捷。     

Scuffing Performance of Amorphous Carbon During Dry-Sliding Contact

Scuffing is a major problem that limits the life and reliability of sliding tribo-components. When scuffing occurs, friction force rises sharply and is accompanied by an increase in noise and vibration; severe wear and plastic deformation also occur on the damaged surface. Attempts have been made over the years to combat scuffing by enhancing the surface properties of the machine elements, and by methods involving lubricant formulation and coating application.

In this study, the authors evaluated the scuffing performance of an amorphous, near-frictionless carbon (NFC) coating that provides super-low friction under dry sliding conditions. The test configuration used a ball-on-flat contact in reciprocating sliding. The coating was deposited on HI3 steel. An uncoated 52100 steel ball was tested against various coated flats in room air. Compared to uncoated surfaces, the carbon coating increased the scuffing resistance of the sliding surfaces by two orders of magnitude. Microscopic analysis shows that scuffing occurred on coaled surfaces only if the coating had been completely removed. It appears that depending on coating type, the authors observed that coating failure occurs before scuffing failure by one of two distinct mechanisms: the coating failed in a brittle manner and by spoiling, or by gradual wear.     

Effect of Carbon Coating on Scuffing Performance in Diesel Fuels

Low-sulfur and low-aromatic diesel fuels are being introduced in order to reduce various types of emissions in diesel engines to levels in compliance with current and impending U.S. federal regulations. The low lubricity of these fuels, however, poses major reliability and durability problem for fuel injection components that depend on diesel fuel for their lubrication. In the present study, the authors evaluated the scuff resistance of surfaces in regular diesel fuel containing 500 ppm sulfur and in Fischer-Tropsch synthetic diesel fuel containing no sulfur or aromatics. Tests were conducted with the high frequency reciprocating test rig (HFRR) using 52100 steel balls and H-13 tool-steel flats with and without Argonne's special carbon coatings. Test results showed that the sulfur-containing fuels have about 20% higher scuffing resistance than does fuel without sulfur. The presence of the carbon coating on the flat increased scuffing resistance in both regular and synthetic fuels by about ten times, as measured by the contact severity index at scuffing. Coating removal was observed to be a necessary, but not sufficient condition for scuffing failure in tests conducted with coated surfaces. The loss of coating from the surface occurred by the two distinct mechanisms of spalling and wear.     

Scuffing resistance of phosphate esters II: Effect of applied voltage

The scuffing resistance of tricresyl phosphate under severe conditions of lubrication was investigated using a reconstructed Timken machine. Although the iron phosphate formed on rubbing surfaces is effective in preventing scuffing under mild lubricating conditions, transformation to iron phosphide is essential to prevent scuffing under severe lubricating conditions. The friction polymer produced during tests is beneficial in increasing scuffing resistance.The formation of surface films is influenced by the electric current flowing between the rubbing surfaces as a result of the formation of a galvanic cell or an externally applied voltage. To prevent scuffing it is beneficial to promote film formation on a surface operating under more severe lubricating conditions than those of the mating surface. However, excessive promotion of surface film formation by the applied voltage decreases scuffing resistance by preventing film formation on the mating surface.     

Scuffing Behavior of Al-Si Alloy Modified by Fine Particle Bombarding and Powder Impact Plating Hybrid Surface Treatment

The occurrence of scuffing is widely observed on tribological components made of Al-Si alloys. The object of this study is to investigate the scuffing behavior of Al-Si alloy modified by fine particle bombarding (FPB) and powder impact plating (PIP) hybrid surface treatment. FPB treatment, PIP treatment, and hybrid treatment consisting of FPB and PIP were conducted on Al-Si alloy samples. The surface morphology, microstructure, and hardness of the samples were examined. Block-on-ring tests were performed to investigate the scuffing resistance of the samples. The test results show that the scuffing resistance of Al-Si alloy depends on the surface hardness and friction coefficient. Scuffing resistance is improved by FPB treatment, which increases the surface hardness by nanocrystallization and reduces the friction coefficient by decreasing the surface roughness and producing a microdimpled surface. PIP treatment reduces the friction coefficient by generating an Sn coating on the surface of the sample, thereby improving the scuffing resistance. After FPB and PIP hybrid surface treatment, the surface hardness is increased and the friction coefficient is further reduced. Therefore, the sample modified by hybrid surface treatment exhibits the highest scuffing resistance.     

Condition monitoring of marine diesel engines through ferrographic oil analysis

The effect of surface hardness on scuffing was investigated using a two-disc machine. The changes in the surface conditions, especially surface roughness, surface hardness and the formation of an oxide film, in the running-in process have a marked influence on the scuffing resistance. Therefore a hard disc does not always have a high resistance to scuffing. In this investigation, quenched discs of the highest surface hardness, in which the improvement in surface roughness and the formation of an oxide film are expected to be small, offered the poorest resistance to scuffing. By contrast, annealed discs of the lowest hardness, in which a diminished surface roughness and an increased surface hardness caused by the work hardening that necessarily accompanies the formation of an oxide film are expected, exhibited a considerably higher resistance to scuffing.     

Scuffing behaviour of salt-bath nitrided steel in loaded lubricated sliding/rolling contacts

The modified 3 in (76.2 mm) David Brown disc machine has been used to investigate the effect on scuffing performance of grinding away various amounts from the surface of nitrided steel discs. The results revealed a systematic deterioration in scuffing resistance as the surface nitrogen concentration decreased, but quantitative correlation between these parameters was hindered by the inadequacies of electron probe X-ray microanalysis as a tool for measuring low nitrogen concentrations. It was concluded that there is no safe depth to which Tenifer-treated (salt-bath nitrided) C15 steel can be ground without impairing its scuffing performance. Other disc tests were carried out to assess the effect on scuffing of phosphate treatment and oil formulation. Results showed that, while phosphate treatment is valuable when running against untreated steel, it is of no benefit against Tenifer-treated steel. On the other hand, the formulation of the lubricant was found to improve the scuffing resistance of Tenifer-treated steel     

Relation between scuffing resistance and the increase in surface hardness during tests under conditions of rolling/sliding

The effect on scuffing resistance of a change in the condition of the rubbing surfaces, especially surface hardness, was investigated using a two-disc machine. Scuffing resistance increased with increasing surface hardness during testing. The increase of surface hardness by work hardening is more beneficial in preventing scuffing than is a change in carbon content or heat treatment. Work-hardened disc surfaces allow surface film formation as a result of plastic deformation. Materials with large Meyer indices and high surface hardness are less prone to scuffing.