快速液压冲击试验台研究

针对矿山岩体力学研究及防冲支护装备、吸能结构承载能力研究中,缺少静载荷和动力载荷复合加载试验设备的问题,提出一种高压快速冲击试验台。该试验台采用液压加载方式,可以对不同结构的被试件进行冲击拉伸和冲击压缩试验。分析了试验台的结构组成及工作原理,阐述了试验台的静态加载、冲击动态加载、静-动复合加载三种加载方式,通过AMEsim软件分析了试验台的响应特性,并用ABAQUSE软件对试验台架进行了有限元分析。样机试制成功后,分别对锚杆等被试件进行了试验研究,结果表明,该试验台的三种加载方式可行,加载系统提供的加载力能够很好的模拟被试件实际工况。该试验台的研制为防冲支护装备的动态特性研究提供了平台,为进一步研究超高能级液压冲击试验台奠定基础。     

传动装置结构振动计算和试验研究

船舶传动装置是船舶结构振动的主要激励源,现有的传动装置振动分析侧重于轴系振动,主要针对轴系的安全性,没有考虑结构振动的影响。论文以试验室传动装置试验台架为对象,用ANSYS有限元软件建立了整个传动装置的试验台架计算模型,通过计算数据和实验数据的对比,验证了有限元计算的可靠性,并通过改变激励条件,研究了船舶传动装置结构振动的传递规律。     

装甲车辆传动装置试验台无损连接制动系统研究

传动装置试验台无损连接制动系统是传动装置试验台大转矩原位校准系统的重要组成部分,可实现对装甲车辆大转矩传动轴的无损连接制动.为了在满足现场空间要求的前提下保证原位校准的准确性,本文设计了一套与现场大转矩动力输出装置相匹配的无损连接制动系统.该系统不仅适用于现场狭小空间,而且可根据传动装置试验台输出转矩的大小提供与之匹配...     

传动装置结构振动计算和试验研究

摘要：船舶传动装置是船舶结构振动的主要激励源,现有的传动装置振动分析侧重于轴系振动,主要针对轴系的安全性,没有考虑结构振动的影响。论文以试验室传动装置试验台架为对象,用ANSYS有限元软件建立了整个传动装置的试验台架计算模型,通过计算数据和实验数据的对比,验证了有限元计算的可靠性,并通过改变激励条件,研究了船舶传动装置结构振动的传递规律。     

手动伺服控制液压系统

前言近年国外生产的液压传动混凝土搅拌车,大多采用美国森斯传德公司(Sundst-rand)的静液压传动装置,如日本大坂金属株式会社(DAIKIN)和西德索尔公司(SAUER),就是向森斯传德公司购买专利和许可证进行生产的。上海电力机械厂研制的 JCQ601混凝土搅     

基于LabVIEW的车体静强度试验台测控系统

车体静强度试验需要通过液压缸对车体进行作用力加载。针对传统车体静强度试验台手动调节液压缸作用力操作复杂、精度低以及试验台信息化程度低、监管困难等问题，基于LabVIEW设计了车体静强度试验台测控系统。基于LabVIEW开发了该测控系统上位机软件，在控制算法上，针对液压缸加载特性和系统安全性、鲁棒性的要求，对PID（proportion integration differentiation，比例积分微分）算法进行改进并基于自适应算法对PID参数进行调整；选择S7-200 SMART PLC（programmable logic controller，可编程逻辑控制器）作为下位机来对液压泵站进行控制，上、下位机间采用OPC（object linking and embedding for process control，过程控制中的对象链接和嵌入）技术进行通信；基于以太网开发了试验台信息化系统，并设计了信息化流程。试验结果证明：该测控系统实现了对液压缸作用力的快速、准确控制，具有较强的安全性和鲁棒性；达到了对液压泵站远程操作、数据实时采集及对试验台信息化管理的目标。该测控系统可推广至需对液压缸作用力进行自动控制和对系统信息化要求较高的实际应用中。     

履带车辆行星传动装置疲劳寿命的仿真及预测

行星传动装置是履带车辆的重要传动机构,由于没有准确的载荷数据,因此采用静载荷设计行星传动装置。由于静载荷和实际载荷的差距相当大,因此行星传动装置在使用过程中故障率较高,导致整车可靠性低。为解决实际工况下行星传动装置动态载荷的难题,基于ADAMS.ATV建立履带车辆行星传动装置虚拟行驶试验平台,获得了行星传动装置各零部件的动态载荷。基于FE-Fatigue软件建立了行星传动装置的疲劳分析模型,获得了行星传动装置关键/重要部件的疲劳寿命。预测仿真实例证明了对行星传动装置构件进行疲劳寿命预测的可行性,解决了复杂工况载荷条件下履带车辆行星疲劳寿命的预测难题,研究成果还可推广应用于相关工程领域,具有非常重要的实用意义。     

公路机械挖掘机工作异常情况分析

液压系统是挖掘机最重要的系统之一,也是最容易出现故障的系统之一,本文分析了液压系统结构特点和工作原理及故障的分析和排除,以对挖掘机及其他含有液压传动装置的设备的检修起到一定的指导作用。     

哈克铆钉横向振动试验台设计

为应对铁路货车铆钉质量强制抽验的要求,设计研制出哈克铆钉横向振动试验台。试验台利用液压伺服作动器进行加载,采用LabVIEW软件平台和相应硬件,构建基于虚拟仪器的测试系统,实现对哈克铆钉质量检验以及对检验结果进行存储、查询、打印等功能。测试结果表明所设计的哈克铆钉横向振动试验台方案正确。     

一种液压泵马达测控实验台功率回收率的分析

本文介绍了一种功率回收型液压泵马达试验台系统,阐述了其工作原理,对其功率回收效率进行了理论计算,并通过现场试验进行验证,为技术人员在设计带功率回收系统的液压马达试验台时提供了一定的参考。     

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.