关于如何确定衡器检定周期的建议

本文主要介绍了衡器检定周期验证的目的和意义,并通过分析我国衡器检定规程规定的检定周期,以及国内外实际执行的检定周期的情况,提出合理化建议。     

总辐射表计量检定设备自动化检测系统设计

为了保证总辐射表计量检定系统本身量值的可靠性和精度,研究设计了一种总辐射表计量检定设备自动化检测系统。从功能检测和性能检测两个方面对总辐射表计量检定设备自动化检测系统进行了硬件和软件的详细设计。本文所设计的自动化检测系统能够满足总辐射表计量检定设备的设备正常化检测和量值稳定性检查需求,确保了总辐射表计量量值传递的准确、可靠。     

TP45型吊管机吊臂结构的有限元分析及试验验证

吊臂是履带式吊管机的关键部件,其强度和重量影响起吊性能的好坏,所以针对吊臂结构的分析研究是很有必要的。根据履带式吊管机的施工特点,以TP45型履带式吊管机吊臂为研究对象,利用ANSYS软件对其结构进行载荷计算和有限元建模分析,通过校核等效应力值、变形量和许用值的大小,得出吊臂强度和刚度符合设计要求。最后通过试验验证和对比分析,得出有限元分析方法具有一定的可行性和参考性,能够有效避免大量的型式试验工作,对吊管机吊臂的改进和制造工作起到一定指导作用。     

谈谈电子汽车衡首次检定中注意的问题

本文主要介绍电子汽车衡首次检定之前、检定中及大秤量电子汽车衡偏载测试方式等问题,目的是使电子汽车衡首次检定一次通过。     

浅谈地面气象月报表审核软件的应用

本文介绍自动气象站地面业务软件、质量控制软件、、浙江审核等软件在地面气象记录月报表预审工作的应用,并提供缺测或疑误数据的判断和处理方法,以减少月报表中出现不必要的错误,提高月报预审的质量。     

智能制造装备数字化设计与验证系统研究

智能制造装备的设计水平不高是制约我国装备制造业发展因素之一。在阐述智能制造装备特点的基础上，提出了一种基于CORBA规范的智能制造装备数字化设计与验证系统的体系结构，并探讨了实现该系统的关键技术。该系统的目的是降低智能制造设备开发成本，缩短开发周期，提高智能制造装备的设计质量。     

A new partitioning process for geometrical product specifications and verification

In ISO Geometrical Product Specifications and Verification Standards (GPS), Feature operations are used to obtain ideal and non-ideal features. The formalization of such operations enables to reduce ambiguity and uncertainty within the activities of design, manufacture and metrology of mechanical products, and their scientific investigation contributes to develop a sound mathematical framework and formalisms for the comprehension of engineering practices and the development of new standards. Partitioning is a fundamental operation defined in ISO GPS standard which aims at decomposing a part into independent features or surface portions for further processing and analysis. In this paper, a state-of-the-art survey of partitioning and segmentation methods and techniques reported in the literature is conducted and a comprehensive classification is proposed. Thereafter, a new partitioning process is developed for partitioning into regions and recognizing each region as one of the seven invariance classes of surfaces. It proceeds in three main steps: initial partitioning based on shape index and curvedness, refined partitioning by slippage analysis and invariance class recognition by statistical evaluation. An intuitive shape color wheel is defined to visualize the partitioned features according to their corresponding invariance classes. Experiments and results on both nominal models and measured point clouds are presented to demonstrate the effectiveness of the proposed method.     

舰船用气体分析仪检定装置的研制

研制了一种适合于舰船用气体分析仪的检定装置。舰船用气体分析仪检定装置采用气体混合比例泵动态配气,通过电路测试模块、波形测试模块、计算机数据采集模块对船用气体分析装备的主机及其接口的特征信号进行采集和诊断分析,检测所得信号与计算机进行双向通讯,由计算机命令各个诊断模块,然后由计算机中已存数据库与诊断数据相比较,从而自动诊断出船用气体分析仪的误差、稳定性、反应时间、灵敏度等各个技术参数的真实情况。通过计算机软件显示、存储、计算后,将各个参数绘成统一的报表,可直观、方便的辨别出舰船用气体分析仪器性能指标是否正常,达到对舰船用气体分析仪器的性能检测和故障诊断的目的。     

电子秤检定步骤的优化探讨

文章以数字指示秤检定规程为依托,对检定中采用的闪变点方法进行了分析,提出了优化检定步骤的方法。     

高速公路自动气象观测站现场核查方法

结合《区域自动气象站现场核查方法》,安徽省气象部门对安徽省高速公路自动气象观测站展开了现场核查。文章主要针对温度、湿度、风向、风速和雨量5个要素的传感器进行现场核查,以保障高速公路自动气象观测站各要素测量数据的准确可靠。     

Decomposition of process damping ratios and verification of process damping model for chatter vibration

In the previous study, by the same authors, titled “A new process damping model (PDM) for chatter vibration (Measurement, 44 (8) (2011) 1342–1348)”, a new approach has been presented for obtaining process damping ratios (PDRs). This PDM has been constituted on the basis of the shear angle (φ)$(\phi )$ oscillations of the cutting tool and the alteration of the penetration forces when they penetrate into the wavy surface. Variation and quantity of PDR are predicted by reverse running analytical calculation procedure of traditional Stability Lobe Diagrams (SLDs). In this study, firstly, how the PDM in previous study results with different materials such as AISI-1050 and Al-7075 are examined. Then, two problems are solved: how much of the total PDR of cutting system is caused by the tool penetration and how much is caused by (φ)$(\phi )$ oscillation? Finally, verification of PDR values and PDM are performed by energy equations.     

Specification Model: A First Step Towards Automatic Interpretation of Injection Moulding CAE Results

The use of CAE software, such as Moldflow ?, in the plastic industry is well established. The software is useful in simulating and visualising the performance of the injection moulding process. Nevertheless, the high level of expertise needed to use it has been one of the major obstacles in its further application. One obstacle is in interpreting analysis results. The facilities for the designers to specify verification and evaluation criteria or to interpret analysis results in terms of specified information are yet to be developed. As a first step to tackle this problem, this paper proposes a specification model approach. The model integrates analysis and evaluation information with a CAD model of a plastic part. It allows designers to specify their intended verification and evaluation criteria directly for the CAD design model. The same model is used to activate Mold flow to conduct the relevant analyses, and to extract data automaticaly from the analysis results to verify and evaluate the designs. A software prototype has been developed and a design case study is presented to illustrate the proposed approach. ID="A1"Correspondance and offprint requests to: Dr Y.-M. Deng, CAD/CAM Lab, School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. E-mail: mymdeng@ntu.edu.sg     

A comparative study on the use of calibrated and rainbow schlieren techniques in axisymmetric supersonic jets

Detailed experimental comparisons had been conducted between calibrated and rainbow schlieren on perfectly- and under-expanded axisymmetric supersonic jets through a modified Z-type schlieren system. The techniques were implemented by using a weak lens in the field-of-view to provide calibration information for the extraction of quantitative density gradients from the experimental schlieren images. Sixth-order polynomial curve fits were obtained for both calibrated and rainbow schlieren respectively. The effects of light inhomogeneity caused by the mirrors and system diaphragm aperture had been evaluated for the colour images and results indicate that averaging the background hue is an acceptable approach for minimizing light variations with less than 2% experimental error. Density gradients as calculated via Abel transform have also been evaluated to validate the two different set-ups. Additionally, experimental results have been compared to validated numerical results and they show that calibrated schlieren is able to predict density gradients within 2% of the numerical results. This is significantly more superior to rainbow schlieren, where errors in the estimated density gradients are closer to 20%. It is shown here that rainbow schlieren results are more adversely impacted by the system diaphragm aperture, especially for vertical light cut-off configuration. This is partly due to the loss of sensitivity of the schlieren system, as well as potential light diffusion caused by the filter.     

噪声鲁棒性说话人识别语音高频加权MFCC提取

本文提出了一种可提高噪声环境下的说话人确认识别率的语音MFCC参数高频加权方法.由于Mel频率与线性频率成对数关系,频谱能量在高频部分分辨率逐减,而语音经过基音同步可变窗长加窗后的语音会在一定程度上避免语音信号的谐波泄露,从而保留更多高次谐波信息.将语音频谱能量高频部分进行加权,则可使语音增强,提高语音鲁棒性.该方法被用于基音同步预处理MFCC参数提取中,并进行了说话人确认实验.实验结果表明,即使在信噪比较低的情况下,该方法都会在一定程度上提高多种噪声环境下的说话人确认识别率.     

Modeling the control of a flexible manufacturing cell for automatic verification and control program generation

Shortened product life-cycles decrease the output rate of manufacturing systems. Offline verification of the control systems promises to increase the output. However, to make offline verification possible some major improvements of the current development process of manufacturing systems are needed. Information handling and development of control programs based on information reuse are two of the most important improvement areas. This paper presents the results of the modeling of a real manufacturing cell according to a previously presented method for offline verification and program generation based on information reuse.     

关于国标皮带秤检定规程对用户要求的思考

本文对JJG 195-2002《连续累计自动衡器(皮带秤)》国家计量检定规程附录D中对皮带秤用户的要求(强制性)进行理解和思考,根据本单位实际查找出皮带秤使用中存在的主要问题,并针对这些问题提出整改的建议和对策。     

Data format and browser of lightweight CAD files for dimensional verification over the internet

The demand for the use of 3D CAD data over the Internet environment has been increasing. However, CAD data size has deteriorated the communication effectiveness of 3D CAD files. Good design methodology of a lightweight CAD file is required for rapid transmission on the distributed network environment. In this paper, a file translation system is constructed to produce lightweight CAD files from commercial CAD systems by using InterOp and APIs of the ACIS kernel. Using B-rep models and mesh data extracted from the CAD native files, the lightweight CAD files with topological information are constructed as binary files. As the lightweight CAD files retain topological and geometric information, they are applicable to dimensional verification, digital mock-ups, and visualization of CAD files through a CAD viewer. The effectiveness of the proposed lightweight CAD files is confirmed through various case studies on the CAD viewer. This paper was recommended for publication in revised form by Associate Editor Jooho Choi In-Ho Song received B.S. and M.S. degrees in mechanical engi-neering from Kunsan National University, and Ph.D. degree in mechanical engineering from Hanyang University, Seoul, Korea in 2007. From 2002 to 2007, he served as a team manager to develop CAD and PLM systems in CIES in Korea. He is currently a post-doc researcher in the mechanical engineering department in Hanyang University. As he had developed a lightweight CAD viewing kernel for CAD/CAM systems, he received a New Technology Certificate from Korean Government (MOCIE) in 2005. He also received several prizes from the Korean Society of CAD/CAM Engineers in 2003 and 2004. He specializes in geometric modeling, CAD kernels, product design and digital manufacturing systems. Sung-Chong Chung received the B.S. degree with honors in mechanical engineering from Hanyang University, Seoul, Korea, and the M.S. and Ph. D. in mechanical engineering from KAIST, Seoul, Korea in 1979, 1981 and 1987, respectively. Since 1983, he has been a professor in the School of Mechanical Engineering, Hanyang University, Seoul, Korea. In 2000, he received the outstanding paper award from the North American Manufacturing Research Institution of the Society of Manufacturing Engineers. He received the academic research and software development awards from the Korean Society of Mechanical Engineers and the Korean Society of CAD/CAM Engineers in 2003 and 2004, respectively. His research interests include CAD/CAM, control, mechatronics, manufacturing and precision engineering.     

Analysis of the metal flow in swaging-numerical modelling and experimental verification

The process of swaging using four flat anvils and simple translational feeding, has been numerically analysed by means of the Finite Element Method (FEM). Application of 3D elements, requiring substantial computing time, is necessary in the FEM analysis due to the kinematics of the tools' movement and of the deformed metal and due to the nature of the metal flow in the deformation gap. An attempt has been made to solve the problem of simulation of the stress state and of analysis of the flow scheme in the swaging process using an FEM solution for plane 2D elements and introducing assumptions enabling conversion to to a 3D solution. The assumptions presented lead to an original method of solving the problem of modelling the swaging process and permits a 3D analysis of the behaviour in the deformation gap by considering flat sections occupying consecutive positions between the entrance and exit planes of the analysed deformation gap. The assumptions taken in the model have been verified experimentally. The results of the calculations obtained have been compared with the results of trial forgings produced under industrial operating conditions. The temperature distributions on the band section obtained have also been verified by comparison with pyrometric temperature measurements on the surface of the bars.     

环境参数变化对风速值检定的影响

文章主要研究环境参数温度和湿度在风速值检定中的影响,通过实验给出各湿度点及温度段在实验开始和结束时的环境参数差值对风速值检定结果的影响程度,并提出了减少差值的方法。     

Characteristic verification and parameter optimization of airbags cushion system for airborne vehicle

Abstract： The major methods to investigate the airbags cushion system are experimental method, thermodynamic method and finite element method （FEM）. Airbags cushion systems are very complicated and very difficult to be investigated thoroughly by such methods For experimental method, it is nearly impossible to completely analyze and optimize the cushion characteristics of airbags of airborne vehicle because of charge issue, safety concern and time constraint. Thermodynamic method fails to take the non-linear effects of large airbag deformation and varied contact conditions into consideration. For finite element method, the FE model is usually complicated and the calculation takes tens of hours of CPU time. As a result, the optimization of the design based on a nonlinear model is very difficult by traditional iterative approach method. In this paper, a model based on FEM and control volume method is proposed to simulate landing cushion process of airborne vehicle with airbags cushion system in order to analyze and optimize the parameters in airbags cushion system. At first, the performance of airbags cushion system model is verified experimentally. In airdrop test, accelerometers are fixed in 4 test points distributed over engine mount, top, bottom and side armor plate of hull to obtain acceleration curves with time. The simulation results are obtained under the same conditions of the airdrop test and the simulation results agree very well with the experimental results, which indicate the established model is valid for further optimization. To optimize the parameters of airbags, equivalent response model based on Latin Hypercube DOE and radial basis function is employed instead of the complex finite element model. Then the optimal results based on equivalent response model are obtained using simulated annealing algorithm. After optimization, the maximal acceleration of airborne vehicle landing reduces 19.83%, while the energy absorption by airbags increases 7.85%. The performance of the airbags cushion system thus is largely improved through optimization, which indicates the proposed method has the capability of solving the parameter optimization problem of airbags cushion system for airborne vehicle.