测量系统波动源的分析、控制和软件设计

在生产过程中 ,测量系统的好坏是成功实施质量改进或应用统计过程控制的先决条件。测量系统的性能评价称之为量具的重复性和再现性 (R& R)研究。本文首先根据二因素随机效应模型 ,给出了估计 R& R的一种方法 ,它克服了方差分析方法的某些不足 ;其次 ,当测量系统满足能力要求时 ,提出了监控测量过程的方法 ;最后 ,简单介绍了用于分析和监控测量过程的应用软件     

汽车转向节疲劳寿命分析和试验研究

针对日益突出的汽车转向节疲劳损伤问题,应用CAE技术建立了汽车转向节的实体模型,并对汽车转向节的各种工况开展了静强度分析,通过施加载荷分析得到了汽车转向节的应力结果,然后应用有限元方法对汽车转向节设计模型进行了疲劳分析,得到了相对可靠的零部件预测寿命。利用疲劳试验装置对分析结果满足设计要求的转向节进行了疲劳耐久性试验,验证了有限元模型、静强度分析以及疲劳寿命分析结果的准确性。研究结果表明,应用有限元分析方法进行汽车转向节疲劳分析是可行的,对完善汽车零部件设计开发流程有重要的指导意义。     

Repeatability and Reproducibility techniques for the analysis of measurement systems

This research was conducted with the aim of analyzing two of the main metrological characteristics of any measurement system: Repeatability and Reproducibility. Both of these features play an important role in the analysis of the measurements and they can give us a lot of information about who and what influences any measuring system. The analysis of Repeatability and Reproducibility is generally carried out through the use of the study Gage R&R. This study permits to understand which are the decisive factors in a measurement system, and, definitively, if the process is stable, that is under statistical control or out of statistical control.     

Fibre analysis in 3D materials and process validation on artificial data

The physical properties of fibrous materials are closely linked to their microstructure. In order to characterize their microstructures as effectively as possible, all fibres in a sample should be individualized. This work mainly aims at developing a new fibre analysis method that segments a 3D greyscale tomography image into a background and a set of connected components, each representing a single fibre. Properly completed fibre analyses may provide input data for generative or synthetic models, which can in turn be used to estimate various characteristics of the material. In this paper, we introduce an original method based on the skeletonization of the fibre mass, followed by a geometrical analysis of the obtained skeleton. Based on this procedure, several measurements can be computed (e.g. length, orientation, number of contacts). Furthermore, we validate the reliability of our fibre analysis process using various comparisons between our results and artificial ground‐truth data.     

A mathematical model for the validation of the ground reaction force sensor in human gait analysis

A sensor validation scheme investigates a system that requires control based on monitored sensor readings in order to allow immediate corrective actions in the case of aberrations from a desired value. In this paper, the proposed sensor validation strategy is based on a mathematical model for the calculation and classification of some white noise or faults occurring in the biomechanical system during walking on an instrumented treadmill. This strategy attempts to build a predictive model from measurements to determine whether the actual values are within an expected range. Particular attention is focused on the system used to measure vertical ground reaction force (vGRF) during normal walking on the instrumented treadmill. The aim of the study is to perform sensor validation to improve the resolution and accuracy of the acquired sensor data in order to provide reliable, repeatable, reproducible information for decision making.     

Wavelet spectrum analysis approach to model validation of dynamic systems

Feature-based validation techniques for dynamic system models could be unreliable for nonlinear, stochastic, and transient dynamic behavior, where the time series is usually non-stationary. This paper presents a wavelet spectral analysis approach to validate a computational model for a dynamic system. Continuous wavelet transform is performed on the time series data for both model prediction and experimental observation using a Morlet wavelet function. The wavelet cross-spectrum is calculated for the two sets of data to construct a time-frequency phase difference map. The Box-plot, an exploratory data analysis technique, is applied to interpret the phase difference for validation purposes. In addition, wavelet time-frequency coherence is calculated using the locally and globally smoothed wavelet power spectra of the two data sets. Significance tests are performed to quantitatively verify whether the wavelet time-varying coherence is significant at a specific time and frequency point, considering uncertainties in both predicted and observed time series data. The proposed wavelet spectrum analysis approach is illustrated with a dynamics validation challenge problem developed at the Sandia National Laboratories. A comparison study is conducted to demonstrate the advantages of the proposed methodologies over classical frequency-independent cross-correlation analysis and time-independent cross-coherence analysis for the validation of dynamic systems.     

Mobile measurement of radiofrequency electromagnetic field exposure level and statistical analysis

In this study, radiofrequency electromagnetic field exposure levels were measured as mobile on the main streets of Diyarbakır during a week. The measurements were carried out using high precision spectrum analyzer with an isotropic antenna mounted on the top of a car. With this mobile measurement, large areas were measured in a short time and information about characteristics of electromagnetic environment was obtained quickly. Measurement results showed that measurement values were not in normal distribution and variances between independent variables were not homogeneous. According to Spearman’s rho correlation coefficient, there was no strong correlation between measurement days. In terms of mean electric field values, contribution of each band to total band was arranged as UMTS DL, GSM900 DL, GSM1800 DL, TV4-5, FM, and TV3 band, respectively. It was determined that all measurement values were below the reference levels of the International Commission on Non-Ionizing Radiation Protection.     

On-machine roundness measurement of cylindrical workpieces by the combined three-point method

In this paper, we describe a new differential method for on-machine roundness measurement of cylindrical workpieces, which is called the combined three-point method. This method combines the advantages of the generalized three-point method and the sequential three-point method and can accurately measure roundness profiles including stepwise variations. In the combined three-point method, some data points in the roundness profile evaluated by the generalized three-point method are chosen as the reference points of the standard area and used to determine the relationships among the data groups of the sequential three-point method. An interpolation technique is employed in the data processing of the generalized three-point method to improve the accuracy of the standard area. Theoretical analyses and computer simulations confirming the feasibility of the combined three-point method are shown in this paper. A roundness measurement system using three capacitance-type displacement probes is constructed. The measurement system and the experimental results are also presented.     

Number of distinct data categories and gage repeatability and reproducibility. A double (but single) requirement

Measurement systems analysis has been widely used in many industries, especially those related to the automotive sector as part of statistical process control practices. Over the years, new elements have been added to the initial requirements for system acceptance, centered on the values of repeatability and reproducibility (integrated in indexes as GRR and GRR%). One of these elements, the number of distinct data categories (NDC) has been treated as an independent requirement. In this paper, we show that NDC and GRR are not independent and that they are in fact both linked by an exact relationship. This therefore makes the double requirement redundant, confusing and unnecessary, except maybe to enhance some conceptual questions.     

IHIR636摆式飞剪测试与有限元分析

对IHIR636摆式飞剪进行了扭矩、应力等测试和分析,对上刀架进行了有限元计算.结果表明:飞剪机力能参数计算时,必须考虑剪切时的冲击载荷的影响;冲击载荷的影响用动载系数K2表示,其值为K2=1.65～2.8左右;剪切速度高时,取大值;板厚时,取小值.上刀架具有足够的强度裕量,能够满足产品规格多样化和高强度钢生产的需要;上刀架整个结构体现了等强度设计观点.     

Measurement and analysis of angular velocity variations of twelve-cylinder diesel engine crankshaft

This paper presents the procedures for measuring and analyzing the angular velocity variation of twelve-cylinder diesel engine crankshaft on its free end and on the power-output end. In addition, the paper deals with important aspects of the measurement of crankshaft torsional oscillations. The method is based on digital encoders placed at two distances, and one of them is a sensor not inserted directly on the shaft, i.e. a non-contact method with a toothed disc is used. The principle based on toothed disc is also used to measure the actual camshaft angular velocity of in-line compact high-pressure pump the engine is equipped with, and this paper aims to demonstrate the possibility of measuring the actual angular velocity of any rotating shaft in the engine, on which it is physically possible to mount a toothed disc. The method was created completely independently during long-range development and research tests of V46 family engines. This method is specific for its particular adaptability for use on larger engines with extensive vibrations and torsional oscillations. The main purpose of this paper is a practical contribution to all the more interesting research of the use of engine crankshaft angular velocity as a diagnostic tool for identifying the engine irregular running.     

Differentiation of human hair by colour and diameter using light microscopy,digital imaging and statistical analysis

This research introduces and evaluates a novel method that offers the potential of providing objective criteria to forensic microscopical hair comparisons. The method combines hair diameter with numeric characterisations of red, green, and blue colour content as determined with the use of digital imaging at defined locations of the hair. Thirty hairs were collected from each of twenty participants, all with naturally coloured brown hair. The hairs were examined with an Olympus BX53® polarising light microscope and digital images were viewed with an Olympus DP72® camera under 400× magnification. Using Olympus cellSens^? Entry software, hair diameter was measured at 1000, 1500 and 2000 m from the base of the root. The Olympus cellSens^? Entry software uses a red, green and blue (RGB) colour model to quantitatively define the colour of each pixel on an image based on its composition of these three principal colour components. This software was used to collect numerical characterisations of hair colour at each distance interval. The diameter and colour values for each hair were compared using discriminant analysis (DA) and principal component analysis. Although a large amount of intrapersonal variation was observed, the degree of interpersonal variation was greater and enabled the statistical model to differentiate between the hair samples from each participant. The DA model achieved sample reclassification with an error rate of 7.33%. A validation study was conducted on a subset of hair samples from which 18 of the 20 were correctly assigned to the participant from whom they originated. These results support the potential of this method to provide an objective addition to current microscopical hair comparison practices.     

流动注射式水质在线测控系统的研究

以工业用水主要水质成分为研究对象,应用水质成分化学反应原理、新型化学流路设计理念、光电传感技术、计算机技术,研制了流动注射式水质在线测控系统。该系统除了具有传统水质监测的功能,还可控制有关的各类机械和电器硬件,实现了测控合一的水质分析自动化处理。相对传统水质分析仪器来说,结构简单、精度高、可靠性好、通用性强,提高了水质分析的速度、精度和自动化程度。     

Thermoelastic and vibration analysis of functionally graded cylindrical shells

The static response and free vibration of metal and ceramic functionally graded shells are analyzed using the element-free kp-Ritz method. The material properties are assumed to vary continuously along the depth direction. The displacement field is expressed in terms of a set of mesh-free kernel particle functions according to Sander's first-order shear deformation shell theory. The effects of the volume fraction, material property, boundary condition, and length-to-thickness ratio on the shell deflection, axial stress, and natural frequency are examined in detail. Convergence studies of node numbers are performed to verify the effectiveness of the proposed method. Comparisons reveal that the numerical results obtained from the proposed method agree well with those from the classical and finite element methods.     

光滑工件尺寸的测量与检验及其计算机实现

在生产实践中，对光滑工件的测量与检验需要查找国家标准规定的数据表格，然后经过一定的数值计算，才能选择出合适的计量器具并给出相应的验收尺寸。手工的查找和计算数据既浪费时间，又易出错。这里采用最新的国家标准GB／T3177—1997（光滑工件尺寸的检验），改变了以往单一的内缩验收方式。根据工件的功能要求，同时考虑到实际的加工工艺能力和现场拥有的仪器现状综合选择计量器具，并应用VB6．0语言开发了应用软件，将以上工作由计算机来完成，提高了检验效率和检验的准确率，降低了检验成本。     

Measurement method for the objective and early detection of the osteosarcoma tumors

This paper deals with the characterization, by means of measurement techniques typically used for ceramics and polymeric materials, of human bone samples affected by two aggressive tumors: osteolitic osteosarcoma and sclerotic osteosarcoma. These two common forms of osteosarcoma often affects children and young teenagers. To distinguish between healthy and diseased bone tissue, the Hydroxyapatite/Collagen ratio and the Hydroxyapatite composition (Calcium/Phosphorus molar ratio) are evaluated. The results allow two considerations to be drawn on the analysis of human bone samples. The first consideration is that the bone affected by osteosarcoma has a greater amount of Collagen with respect to the healthy one. This can be used to evaluate the pathologic status of bone tissues. The second consideration is that the Calcium/Phosphorus molar ratio is, with respect to the one of healthy bone, higher in bone tissue affected by osteolitic osteosarcoma, while is lower in the one affected by sclerotic osteosarcoma. On the basis of these considerations, a promising measurement method is proposed to support the early and objective detection of the osteosarcoma tumor and to distinguish between osteolitic and sclerotic forms. The proposed measurement method can be executed in a few minutes and by using few milligrams of bone tissue that can be drawn with a needle under local anesthesia.     

The simulation and error analysis of raindrop size distribution obtained by micro rain radar

Observation of raindrop size distribution( DSD) with a vertically pointing micro rain radar( MRR) has important significance in the precipitation measurement field. The Mie scattering of large particle,vertical wind and air turbulence have great influences on the retrieval of DSD measured by MRR. This paper simulates the process of how three factors affect the inversion of DSD and the calculation of other precipitation parameters,then makes the errors analysis. Because the wavelength of MRR is 12.5mm,M ie theory is more suitable for the precipitation particle than Rayleigh approximation,w hich may cause the underestimation of number density of small droplets and the overestimation of that in middle field. The vertical wind results in inaccurate estimation of particle terminal velocity,so the diameter is measured with some errors by empirical relationship,w hich affects the calculating accuracy of radar reflectivity and rain rate. Air turbulence can broaden the pow er spectral density,of which the impact on the inversion of DSD are concentrated in small droplets field. Then the measured data from MRR is analyzed and the results prove the impacts of those factors. Finally,according to the analysis and application limits,the prospect of the future research trend of particle size distribution is conducted.     

电动单梁起重机使用情况调查统计分析

通过对使用单位电动单梁起重机使用情况调查统计分析,找出了起重机常见故障部位、故障现象和故障原因,以期引导生产单位提高产品质量和维保水平,同时为检验检测机构提供参考进而提高其检验工作的针对性。     

Measurement of ion and electron temperatures in plasma blobs by using an improved ion sensitive probe system and statistical analysis methods

We have measured ion temperature as well as electron temperature in plasma blobs observed in a linear plasma device by using an improved ion sensitive probe. Current-voltage characteristics of the ion sensitive probe inside and outside plasma blobs were re-constructed with a conditional sampling method. It is clearly found that both ion and electron temperatures in plasma blobs decrease more slowly in a cross-field direction than those in a bulk plasma without plasma blobs.     

浅谈燃油加油机检定周期内计量超差的原因及防范措施

随着我国经济发展,汽车已成为老百姓的生活必需品,然而国内油价飞涨,人们对加油机计量准确的关注度越来越高。本文从专业角度分析了加油机产生计量超差的原因,提出对加油机管理的“四分离”模式,有效防范和减少计量超差的产生。