JJG195-2002皮带秤检定规程主要内容介绍及实施

本文介绍了皮带秤检定规程在制定中新增加的内容,与原规程相比较作了哪些修改,针对规程中存在的不足,阐述了自已的见解,真实地反映了在电力系统调研中规程实施的情况。循环链码必须经实物检定合格后,进行修正,是落实具体实施规程的一项重要措施。     

JJG195-2002皮带枰检定规程主要内容介绍及实施

本文介绍了皮带秤检定规程在制定中新增加的内容,与原规程相比较作了哪些修改,针对规程中存在的不足,阐述了自已的见解,真实地反映了在电力系统调研中规程实施的情况.循环链码必须经实物检定合格后,进行修正,是落实具体实施规程的一项重要措施.     

浅析EOP规程在快堆事故规程体系的应用

事故规程作为核电厂规程体系的一部分,指导核电厂在事故工况下的工作,是将反应堆从事故状态引入安全状态的指导文件。本文介绍了目前核电厂常用的事故规程体系,论述了钠冷快堆事故规程体系的选取和完善方法。     

发动机零件机械加工工艺规程工序图表文件改进

机械加工工艺规程图表文件是零件加工的具体指导文件,工艺规程的内容体现了总体工艺的水平,也决定了零件的加工质量。针对传统工艺规程存在的不足,改进了零件机械加工工艺规程图表文件,改进后的工艺规程内容全面、详细、唯一,能够保证现场零件加工方法的一致性及可靠性,解决零件加工质量过分依靠工人技能的问题,尤其在零件大批量生产过程中,优势更加明显。本文对新工艺规程每部分的格式、作用及编制方法进行了介绍。     

浅谈翻车机轨道衡的检定

本文简单介绍了翻车机轨道衡检定规程编制原因及变化过程,分析了新旧两种规程下检定方法及允差的差别。提出了新规程带来的不利影响及解决方法。     

执行"JJG30-2002通用卡尺"新计量检定规程的体会

本文介绍了“JJG30-2002通用卡尺”新检定规程的主要修订内容,新规程的优点,执行新规程应注意的问题。     

会议

浙江召开《地源热泵系统工程技术规程》编审会 2010年11月10日,浙江省《地源热泵系统工程技术规程》编审会在杭州文华大酒店召开。会上,浙江省建筑科学设计研究院、《规程》的编审专家和教授以及部分企业代表进行了广泛的交流,大家对《规程》的编审提出了宝贵的意见,为加快促进浙江省《地源热泵系统工程技术规程》的编制工作作出了一定的贡献。     

CAPP系统工程化的关键技术研究

对CAPP系统的可靠性、实用性、通用性进行了研究 ,设计了CAPP系统的总体框架 ,并从建立工艺规程模板、工艺规程规范化、所见即所得、工艺规程管理等方面使CAPP的实用性得到了改进     

原子荧光光度计新旧检定规程对比

本文主要从规程适用范围、计量性能要求、捡定方法等方面入手,较全面地解读了原子荧光光度计新旧检定规程的差异,为广大从事仪器检定及期间核查的技术人员提供了参考。较旧规程而言,新规程更具科学性、严格性、可操作性,统一并规定了严格的新旧被检仪器的计量性能,且科学地提出了利用模拟荧光信号来简化通道间干扰的测量。综上所述,新规程能很好地满足当前仪器检定及期间核查工作的需要。     

对JJG 14-2016《非自行指示秤》检定规程的解析

本文对JJG 14-2016《非自行指示秤》检定规程的主要修订内容进行了解析,阐明了与原规程JJG 14-1997的主要不同,以便于读者对新规程的理解和应用。     

Effects of prebuckling deformations on the elastic flexural-torsional buckling of laterally fixed arches

The effect of the prebuckling in-plane deformations on the elastic flexural-torsional buckling of laterally fixed circular arches is studied in this paper. The finite strains and the energy equation for the flexural-torsional buckling of arches have been derived based on an accurate orthogonal rotation matrix. A closed form solution for the elastic flexural-torsional buckling resistance of laterally fixed arches in uniform bending, including the effects of the prebuckling deformations, is obtained. It is found that the notion that the prebuckling deformations increase the flexural-torsional buckling moment of an arch or of a beam is not necessarily correct for a laterally fixed arch or beam in uniform bending, in deference to a laterally pinned arch. When a laterally fixed arch is subjected to positive uniform bending, the effects of the prebuckling deformations decrease the buckling moment, and the reduction of the buckling moment increases with an increase of the included angle and of the out-of-plane slenderness ratio of the arch. When a laterally fixed arch is subjected to negative uniform bending, the effects of the prebuckling deformations decrease the absolute value of its buckling moment when the included angle is very small, but increase the absolute value of the buckling moment when the included angle exceeds a certain value. The increase in the absolute value of the buckling moment increases with an increase of the included angle and of the out-of-plane slenderness ratio of the arch. When the ratio of the out-of-plane to the in-plane second moments of area of the cross-section is not small, both the reduction of the buckling moment of a laterally fixed arch in positive uniform bending and the increase of the buckling moment of a laterally fixed arch in negative uniform bending, are substantial.     

PHENOMENON OF CARVED DRIVING WHEELS

A newly found phenomenon of carved driving wheels of a rear-wheel-drive tractor used in an airport is discussed. The circum of every driving wheel is damaged at three regions,which distribute regularly and uniformly. Everyday,the tractor tows a trailer which are times heavier than the tractor,and moves on the same road in the airport. The phenomenon is explained by the torsional self-excited vibration system of the powertrain. The simplified torsional vibration system is discribed by a 2-order ordinary differential equation,which has a limit circle. Experiments and numerical simulations show the followings: Because of the heavy trailer,the slip ratio of the tractor’s driving wheels is very large. Therefore,there is severe torsional self-excited vibration in the tractor’s drivetrain,and the self-excited vibration results in severe and regular fluctuations of the rear wheel’s velocity. The severe fluctuations in velocity fastens the damage of the driving wheels. At the same time,the time interval in which an arbitrary point in the circum of the driving wheel contacts with the road twice is two times more than the period of the torsional self-excited vibration,and this times explained the existence of three damaged regions. At last,it points out that the phenomenon can be avoided when the torsional damping is large enough.     

DESIGN AND CAD SYSTEM OF THE FOOL FOR DRILL FLUTE

Based on the principles of differential geometry and kinematics, a mathematical model is developed to describe the grinding wheel axial cross-section with the radial cross-section of the flute in a given drill under the basic engagement condition between the generating flute and the generated grinding wheel (or disk milling tool). The mathematical model is good for the flute in the radial cross-section consisting of three arcs. Furthermore, a CAD system is also developed to represent the axial cross-section of the grinding wheel (or disk milling tool). With the system, the grinding wheel (or disk milling tool) axial cross-section that corresponds to the three-arc flute cross section can be conveniently simulated. Through the grinding experiment of drill flutes, the method and the CAD system are proved to be feasible and reasonable.     

孔隙阀式磁流变阻尼器准静力分析

建立了孔隙阀式磁流变阻尼器的轴对称模型.推导了孔隙阀内磁流变液压力梯度方程.对Herschel-Bulkley模型的磁流变阻尼器压力梯度进行了数值求解.应用代数方程理论,得到了Bingham模型的磁流变阻尼器压力梯度的解析解.最后,结合算例计算了孔隙阀内磁流变液的流速分布及阻尼器的阻尼力.     

车门静态强度的有限元分析模拟

轿车门系统结构设计与优化是整车开发过程中的重要环节。车门的强度直接关系到整车在冲击、碰撞等载荷下的安全问题,车门结构静态强度的计算分析,在车门结构设计进程中非常重要。文中首先简要介绍了静态强度所涉及到的非线性有限元的基本理论,然后以某中高级轿车前车门为例,利用计算机辅助分析车门的静态强度,考虑变形的非线性因素,通过对车门的非线性有限元求解来分析车门强度,由计算所得到的车门强度性能指标来指导车门的结构设计。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.     

OPTIMIZING DESIGN OF MECHANICAL SELF-CENTERING DEVICE FOR SUSPENSION HEIGHT

Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.     

平面应变颈缩扩展与剪切断裂的数值模拟

采用虚功率增率有限元法及Ｊ２形变理论，模拟韧性金属平面应变颈缩扩展，剪切断裂演化过程。运用载荷控制的自动识别方法以及各增量步间Ｅｕｌｅｒ控制方法，实现了均匀变形与非均匀变形临界状态的稳定过渡，采用本构方程的Ｅｕｌｅｒ显式积分，对Ｊ２形变理论塑性加载与弹性卸载的不连续性进行了改进，保证了变形局部化模拟过程的可靠性，最后，讨论了不同硬化指数及初始几何不均匀性对局部化力学行为的影响。     

IMPROVED METHOD FOR HILBERT INSTANTANEOUS FREQUENCY ESTIMATION

In the mechanical fault detection and diagnosis field, it is more and more important to analyze the instantaneous frequency (IF) character of complex vibration signal. The improved IF estimation method is put forward aiming at the shortage of traditional Hilbert transform. It is based on Hilbert transform in wavelet domain. With the help of relationship between the real part and the imaginary part obtained from the complex coefficient of continuous wavelet transform or the analytical signal reconstructed in wavelet packet decomposition, the instantaneous phase function of the subcomponent is extracted. In order to improve the precise of IF estimated out, some means such as Linear regression, adaptive filtering, resampling are applied into the instantaneous phase obtained, then, the central differencing operator is used to get desired IF. Simulation results with synthetic and gearbox fault signals are included to illustrate the proposed method.     

The effect of basic nitrogen compounds on the tribological performance of sulphurised olefin

The effect of the molecular structure of basic nitrogen compounds on the lubricating properties of sulphurised olefin has been investigated using a Timken tester. X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Analysis (EDAX) were used to study the chemical states of sulphur and nitrogen on the rubbed surfaces and the reaction rates of sulphur and iron separately. It was found that the antiwear and friction reduction properties of sulphurised olefin are greatly influenced by the different molecular structures of the basic nitrogen compounds. A composite additive package containing basic nitrogen compounds with sulphurised olefin can produce either synergistic or antagonistic effects, due to the influence of the different molecular structures of the basic nitrogen compounds. XPS analysis revealed that a tribochemical protective film containing nitrogen and sulphur was formed on the rubbed surface. EDAX analysis indicated that the reaction rates between elemental sulphur and iron were influenced by the different molecular structures of the basic nitrogen compounds. It was found that the apparent reaction rates of elemental sulphur and iron are related to the tribological characteristics of the additive package.