Experimental studies on the effects of reduction in gear tooth stiffness and lubricant film thickness in a spur geared system

Gears are one of the most common mechanisms for transmitting power and motion and their usage can be found in numerous applications. Studies on gear teeth contacts have been considered as one of the most complicated applications in tribology. Depending on the application, the speed and load conditions of teeth may change triggering several types of failures on teeth surface such as wear, scuffing, micro-pitting and pitting. The above-mentioned faults influence changes in vibration and acoustic signals, due to changes in operating conditions such as increase in temperature and decrease in lubricant film thickness and specific film thickness. These abnormal changes result in cumulative effects on localised or distributed faults on load bearing surfaces of gears. Such damages cause reduction in tooth stiffness and severity of damage can be assessed by evaluating the same using vibration-based signals.This paper presents the results of experimental investigations carried out to assess wear in spur gears of back-to-back gearbox under accelerated test conditions. The studies considered the estimation of operating conditions such as film thickness and their effects on the fault growth on teeth surface. Modal testing experiments have been carried out on the same gear starting from healthy to worn out conditions to quantify wear damage. The results provide a good understanding of dependent roles of gearbox operating conditions and vibration parameters as measures for effective assessment of wear in spur gears.     

Application of the concentration-dependent surface diffusion model on the multicomponent fixed-bed adsorption systems

The ability of bone char to adsorb three metal ions, namely, cadmium, copper and zinc, from effluents in fixed beds has been studied. Two binary metal ion sorption systems, Cd+Cu and Cu+Zn, have been investigated. The variables studied include metal ion solution flowrate, initial metal ion concentration, and bone char particle size bed height. The experimental breakthrough curves for each binary system were measured at five bed heights.A multicomponent film-surface diffusion model has been developed to predict the breakthrough curves by incorporating the IAS for both the Langmuir and the Sips equations, since they both correlate the single component equilibrium isotherm data well. A novel development is the modification of the solution methodology, previously restricted to a constant diffusivity, to incorporate a variable diffusivity correlated with adsorbent coverage by the constant self-diffusivity. The self-diffusivities for the metal ions have been evaluated.     

插齿刀CAD系统的设计与加工过程仿真

插齿刀CAD系统一直是机械加工企业的攻关课题。本文介绍了利用“综合图法”合理选择变位系数，并在VC下开发了具有三维造型与加工过程仿真功能的插齿刀CAD系统。     

从种分槽减速机的改进谈优化齿轮副参数的作用

介绍种分槽减速机齿轮轴齿轮副的改进情况,比较优化前后齿轮轴的接触强度和弯曲强度,说明优化齿轮副参数的作用。     

改性碱法制浆废液降低聚合物泥浆粘度的室内研究

本文介绍了碱法蔗渣制浆废液与丙烯酸、甲基丙烯酸甲酯、丙烯酰胺、一种有机络合剂等直接反应，制备改性碱法制浆废液的方法，研究了该改性制浆废液在膨润土浆和聚合物泥浆中的降粘性能，探讨了降粘机理。结果表明，该改性制浆废液在聚合物泥浆中的降粘能力大大超过ＦＣＬＳ，在膨润土浆中的降粘能力在加量超过约１８０ｍｇ／ｌ后略高于ＦＣＬＳ。     

Design of circular steel arches with hollow circular cross-sections according to EC3

Design of either pin-ended or fixed circular steel arches with hollow circular cross-sections subjected to a uniformly distributed vertical load along the horizontal projection of the entire arch with the aid of the EC3 provisions is discussed. Appropriate modification factors are proposed that should be included in EC3 interaction equations, to improve their accuracy for the design of such arches.     

信息通信网发展演变的若干探析

以勘察设计的经历，从技术先进、适用、可持续发展和升级、安全可靠、可建设和可维性出发，对当前信息与通信网的急剧发展、渗透和综合后出现的信息新技术和闪烁的通信新亮点进行了一些探讨性分析。     

Simulation and Optimization of an Adiabatic Multi‐Bed Catalytic Reactor for the Oxidation of SO2

A software package was developed for the simulation and optimization of a multi‐bed adiabatic reactor for the catalytic oxidation of SO₂, using a heterogeneous plug flow model. The orthogonal collocation (OC) technique with up to eight collocation points was used for the solution of a nonlinear, two‐point boundary value differential equation for the catalyst particle, and it was shown that the use of the OC technique with two collocation points can describe the system well. Because of the nonlinear behavior of the effectiveness factor along the bed, optimal catalyst distribution between the beds and corresponding inlet temperatures were determined by two methods, including: the use of (1) intrinsic or (2) actual rate of reaction in the optimization criteria. The results showed that for the second case, the minimum amount of the catalyst can be reached at lower temperatures, the amount of catalyst required is always less, and the number of beds is greater than or equal to that of the first case.     

少齿差行星齿轮齿根弯曲应力计算方法研究

少齿差齿轮副在啮合时由于轮齿受载产生变形可能引发多对齿同时接触承载的情况[1],啮合齿对实际承担的载荷将下降。少齿差齿轮副啮合时存在多对齿同时接触承载的现象,且由于内外齿轮齿廓的凹凸曲率非常接近,啮合时齿面接触面积较大,接触力为分布力,在计算齿根弯曲应力时不宜按集中力处理,这些情况使得准确计算少齿差齿轮副的齿根弯曲应力变得复杂。现以大量有限元计算分析为基础,综合考虑多对齿同时接触承载这一情况,建立了适用于少齿差齿轮副齿根弯曲应力的计算方法,并进行了实验验证。     

自升式钻井平台悬臂梁齿轮齿条驱动系统设计

以某自升式钻井平台为例,采用"电机+变速箱+小传动轮+齿条"方式驱动悬臂梁移动。通过悬臂梁的结构及悬臂梁上的设备质心确定移动悬臂梁所需的推力。计算悬臂梁齿轮齿条几何参数,并设计悬臂梁与齿轮齿条的连接结构及悬臂梁驱动控制系统,合理配置驱动系统电机功率和减速器传动比。通过采用闭环交流变频控制方式,对悬臂梁速度进行反馈和控制,实现左右两侧悬臂梁的同步移动。