激光干涉法冲击绝对校准的研究

基于ISO 16063-13冲击绝对法校准标准,介绍了基于砧体碰撞的低g值和基于Hopkinson杆的高g值冲击激励机械系统的特点,并模拟了2套系统产生的冲击波形,通过解调零差和外差激光干涉仪的输出信号重构了机械激励系统产生的随时间变化的位移信号,信号处理算法有效地抑制了确定和随机噪声,从而准确地确定了加速度信号的峰值与频谱,仿真、实验以及与绝对法振动校准比较的结果表明,其测量扩展不确定度小于1%(k=2)。     

高精度低峰值冲击加速度绝对法标准装置的研究与建立

介绍建立的一种高精度低峰值的冲击加速度标准装置,该装置利用空气轴承支撑的两根金属棒间的机械碰撞来产生冲击加速度激励,利用外差式激光干涉仪测量碰撞过程中的机械位移量,按照ISO国际标准推荐的算法,结合虚拟仪器技术精确复现冲击加速度物理量,从而实现加速度计的冲击绝对法校准.实验数据表明,该标准装置在冲击加速度峰值小于5000m/s2范围内,测量结果扩展不确定度小于1％(k=2),并且与绝对法振动校准结果比较的En值小于0.1.     

低g值碰撞式冲击加速度计量标准装置研究与建立

研究建立低g值碰撞式冲击加速度计量标准装置,在冲击加速度峰值20~10 000 m/s2及脉冲持时0.5~10 ms内实现基于碰撞式激励半正弦平方波形的加速度计冲击灵敏度激光干涉法高精度校准。校准不确定度为1%,k=2。介绍装置的结构组成及解决的关键技术,描述波形发生的材料种类,给出校准的实验数据及不确定度评估。低g值碰撞式冲击加速度计量标准装置为主导亚太计量规划组织冲击加速度研究性国际比对APMP.AUV.V-P1的主要测量装置。     

高g值加速度传感器激光绝对法冲击校准技术研究

在详细分析反射式激光多普勒原理的基础上,研究了高g值加速度传感器的冲击校准方法。该方法利用Hopkinson杆作为加载手段,利用差动式激光多普勒干涉仪来绝对复现冲击加速度的量值。针对高g值压阻加速度传感器SIMIT-AYZ-60k进行了一系列的校准试验,利用积分运算法和最小二乘法的组合从准动态条件下的校准数据得到了准静态条件下的传感器冲击灵敏度。试验表明,这种方法实现了利用脉宽有限的激励脉冲对固有频率在20kHz以上的高g值加速度传感器的校准,校准的不确定度可以满足冲击测试的工程需求。     

基于激光多普勒原理的超高冲击加速度校准系统

超高冲击加速度传感器在武器研制、航空航天等高过载测量中发挥了重要的作用,为解决超高冲击加速度的校准问题,基于激光绝对法,建立了超高冲击加速度校准系统。本文介绍了系统的组成和优化方案,设计了合适的解调程序和滤波算法,对原始多普勒信号进行解调,实现了冲击加速度峰值1 × 10⁴ g ~ 2.5 × 10⁵ g,脉宽20 ~ 50 μs范围内半正弦冲击波形的绝对复现。最后对影响测量结果的不确定分量进行评定,超高冲击加速度测量不确定度为8%,对2 × 10⁵ g以上冲击加速度校准具有重要意义。     

基于激光绝对法冲击校准技术的动态力测量方法的研究

本文讨论测量原理相似的落锤式动态力标准装置和冲击力法的冲击加速度校准装置的工作原理、力值复现方法 ;分析落锤式动态力标准装置校准方法的缺陷 ;重点介绍瞬态冲击力绝对法校准系统中采用的质量块碰撞式力源、外差式激光干涉绝对法冲击加速度测量技术、有限元法的加速度修正等内容 ;并就我国冲击力标准装置的发展提出建议和设想     

不同冲击激励系统绝对法冲击校准比对可行性的研究

比对是确定不同装置与不同方法之间一致性的主要方法,本文主要论述了基于激光绝对法校准的不同冲击激励系统校准结果比对可行性的问题。首先依据ISO16063-13标准规定的基于刚体碰撞与基于Hopkinson杆的冲击激励系统,分析了其基本原理与典型冲击波形;然后比较了同一只传感器在两种装置上校准结果,说明了结果的差异并分析了原因。最后提出了不同冲击激励系统之间可比性的方法,为冲击校准实验室、区域以及国际比对提供参考。     

基于激光绝对法冲击校准技术的动态力测量方法的研究

本文讨论测量原理相似的落锤式动态力标准装置和冲击力法的冲击加速度校准装置的工作原理、力值复现方法；分析落锤式动态力标准装置校准方法的缺陷；重点介绍瞬态冲击力绝对法校准系统中采用的质量块碰撞式力源、外差式激光干涉绝对法冲击加速度测量技术、有限元法的加速度修正等内容；并就我国冲击力标准装置的发展提出建议和设想。     

一种加速度计冲击校准系统

介绍了一套加速度计冲击校准系统的测试原理和方法,该系统可产生半正弦冲击脉冲,可对压电式、内置电路式和压阻式等多种加速度计的冲击灵敏度进行校准.其中冲击比较校准器通过弹体碰撞装有标准传感器和被校传感器的砧子,进行背靠背式比较校准,其可产生低量程的冲击加速度,可对加速度计进行精确、可控的校准;高g值冲击校准器可产生可控的冲击激励脉冲,共基于Hopkinson棒原理,通过高压气加速弹体碰撞Hopkinson棒,使棒中产生压缩波,并传到装有被校传感器的棒的另一端,系统通过贴在棒中部的应变片测得该点的应变,通过应变与加速度之间的关系式计算出棒末端被校传感器处所受到的冲击加速度值.     

高精度低冲击加速度校准装置研究

基于ISO国际标准设计了碰撞式高精度低冲击加速度校准装置,在冲击加速度峰值20～10000 m/s2,冲击脉宽0.5～10 ms范围内实现产生半正弦波形的冲击加速度传感器的高精度校准.介绍了校准装置的构成和工作原理,通过与冲击加速度国家基准的比对,结果表明本装置可实现0.5％(k=2)的冲击加速度校准不确定度.本装置提...     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.