DIN 53512en

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  2/10/2014 DIN 53512en_  百度文库 http://wenku.baidu.com/view/97d2a9bbfd0a79563c1e7214.html 1/6 新闻 网页 贴吧 知道 音乐 图片 视频 地图 百科  文库 百度文库 专业资料 DIN 53512en 暂无评价  | 0人阅读  | 0次下载  | 举报文档业标准 ICS 83.060Prüfung von Kautschuk und Elastomeren–Bestimmung derRückprall-Elastizität (Schob-Pendel) In keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker. Foreword This standard has been prepared by Technical Committee Prüfung physikalischer Eigenschaften vonKautschuk und Elastomeren  of the Normenausschuss Materialprüfung (Materials Testing Standards Com-mittee), and its specifications with regard to the Schob pendulum correspond to those in ISO 4662.ISO 4662 describes two pendulum designs, the Lüpke and the Schob pendulums. Extensive tests at nationaland international levels have shown that both designs yield similar results provided that the test piecethickness is increased from 6mm to 12,5mm for the Schob pendulum. It is important to keep the frictionof the pendulum low or to allow for correction with friction up to a particular degree. ISO 4662 permits theuse of other designs if the apparent strain density lies within given tolerances, which are sufficiently greatfor both the Lüpke and Schob designs.The standard test temperatures (including tolerances) specified here are those specified in ISO 4662.Clause 3 includes reference to the relationship between rebound resilience and the loss factor, tan   d  , whichis particularly significant for the test piece thickness specified here (12,5mm). However, when these param-eters are compared, it should be taken into consideration that the loss factor is a function of the temperature,frequency and amplitude of oscillation. Since amplitude and frequency are not exactly known, only a roughcomparison can usually be made.  Amendments This standard differs from the December 1988 edition in that use of a maximum pointer with the Schobpendulum has been omitted, and the standard has been editorially revised. Previous editions DIN53512: 1940-12, 1959-01, 1965-12, 1976-07, 1981-03, 1988-12. DEUTSCHE NORM  April 2000 53512 { Continued on pages 2 to 5. Determining the rebound resilience of rubberusing the Schob pendulum SupersedesDecember 1988 edition. Translation by DIN-Sprachendienst. In case of doubt, the German-language srcinal should be consulted as the authoritative text. 1 Scope The method specified here serves to determine the resilience of rubber having a Shore A or IRHD hardnessof between 30 and 85 (see DIN53519-1) when subjected to impact. This method is particularly suitable fora rough assessment of the dynamic behaviour of rubber using simple equipment. When rubber is deformed,it absorbs energy which is partly recovered when it regains its srcinal shape. Energy that is not returned asmechanical energy is dissipated as heat in the rubber. 2 Normative references This standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies. 文档贡献者 wuson 贡献于2 题推荐 名人堂:感受他马云说名人名言精选2中国名人传记史玉柱传奇:巨 手机文库 我的文库 首页 分类 教师频道 个人认证 机构合作 百度文库首页 下载客户端 百度首页 登录 注册  2/10/2014 DIN 53512en_  百度文库 http://wenku.baidu.com/view/97d2a9bbfd0a79563c1e7214.html 2/6 Ref.No.DIN53512:2000-04 English price group05Sales No.0105 11.00©No part of this translation may be reproduced without the prior permission of DIN Deutsches Institut für Normung e.V. , Berlin.  Beuth Verlag GmbH , 10772Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen) . 人堂:众名人带你感受他们的驱动人生 马云 任志强 李嘉诚 柳传志 史玉柱 Page2DIN53512:2000-04DIN53513Determination of viscoelastic properties of rubber under forced vibration beyond reso-nanceDIN53519-1Determination of indentation hardness (IRHD) of soft rubber using standard specimensISO471:1995Rubber – Temperatures, humidities and times for conditioning and testingISO4661-1:1993Vulcanized rubber and thermoplastics–Preparation of samples and test pieces 3 Concept Rebound resilience Rebound resilience, R , is the ratio of energy returned to energy applied.NOTE 1: In the test described here, the resilience is established as the ratio of the height of rebound of apendulum by its height of fall.NOTE 2: For low values of loss factor, tan  d  , the relationship between rebound resilience and this factor isexpressed by R T (1–  p  tan  d   ) (see DIN53513).NOTE 3: The rebound resilience for a given material is a function of:a)temperature, which critically affects resilience near the transition region of the material tested;b)the strain history of the material, which makes mechanical conditioning necessary, particularly in the caseof filler-loaded rubber;c)design-related factors (e.g. type and dimensions of indentor and test piece, and the rate of strain andstrain energy). Factors related to time and strain amplitude have only moderate effects and fairly widetolerances may be admissible for them. 4 Apparatus 4.1 General Rebound resilience shall be measured using a one-degree-of-freedom mechanical oscillatory device. Varioustypes are available, all of which produce similar values for rebound resilience, provided their parameters liewithin the limits specified in subclause 4.2.5. 4.2 Oscillatory device The oscillatory device shall consist of a stand with an anvil, a test piece holder, a pendulum with an indentorand an indicating device. 4.2.1 Frame/Stand and anvil The stand and anvil shall have a combined mass at least 100 times the impacting mass of the pendulum. 4.2.2 Test piece holder The test piece holder shall be designed to ensure that the test piece is held firmly, without lateral restraint beingrequired. Its grip shall be as effective as if the test piece were bonded to the anvil. The difference in reboundresilience of a clamped and bonded test piece shall be less than two units. This condition shall be met for bothhighly resilient (rebound resilience around 90%) and very hard (Shore A or IRHD hardness of 80 to 85) testpieces. The holder may be designed as a mechanical clamping device, a suction holder or as a combination ofthe two. 4.2.3 Pendulum The pendulum shall consist of an arm and a hammer incorporating an indentor with a hemispherical surface (seefigure 1). The pendulum shall be suspended so that it oscillates circularly under the effect of gravity. It shall bepossible to raise the hammer through an angle of 90° from its rest position. With the arm in the vertical position,the indentor shall just touch the test piece surface, the direction of impact of the indentor being perpendicularto the test piece surface. 4.2.4 Indicator The indicator shall, as far as possible, provide for a friction-free measurement of the angle of rebound, a  , fromwhich the rebound resilience, R , is calculated as a percentage, using the following equation: R =(1–  cos  a   )  . 100(1)See also clause 9. 4.2.5 Parameters The pendulum parameters shall be as follows:indentor diameter, D =12,45mm to 15,05mm;effective impacting mass, m =0,247kg to 0,35kg;  2/10/2014 DIN 53512en_  百度文库 http://wenku.baidu.com/view/97d2a9bbfd0a79563c1e7214.html 3/6    2/10/2014 DIN 53512en_  百度文库 http://wenku.baidu.com/view/97d2a9bbfd0a79563c1e7214.html 4/6 Page4DIN53512:2000-04 5.3Impact velocity  The impact velocity, n  , is to be calculated from L re d  using the following equation: red L g  ⋅⋅ =  2 n  (7)It shall be (1,98  t 0,01) m/s (8). 5.4Friction 5.4.1Test set-up  An arrangement similar to that described in subclause 5.2, permitting angles of impact up to 40° and allowingobservation of the rebound angle, shall be used to check for frictional losses. 5.4.2Checking pendulum bearing friction and air friction In order to check the pendulum bearing friction and air friction, the pendulum shall be deflected by about 40°and released. The number of full oscillations until the pendulum stops shall be counted, and shall be greaterthan 300. 5.4.3Error of the indicated rebound resilience The error of the indicated rebound resilience shall be determined in five stages, at about 10%, 20%, 30%,50% or 60%, and 80% of the test scale. The pendulum shall be raised and supported or fixed. The angle ofimpact, a  , shall then be measured using a cathetometer or a spirit level. Uncertainty of measurement shall notbe greater than t 0,065°. The theoretical rebound resilience, R t , is to be calculated, as a percentage, using thefollowing equation: R t =(1–  cos  a   )  . 100(9)where a   is the angle of rebound, in degrees.The indicator error is given by R –  R t , where R  is the rebound resilience indicated by the apparatus. Thepermissible error shall be t 0,5%. 6Test pieces 6.1Test piece preparation Test pieces having a thickness of (12,5 t 0,5)mm and a diameter of 29mm to 53mm shall be used. They shallbe prepared by moulding or cutting and shall have smooth and parallel surfaces. If the surface to be impactedis tacky, it shall be dusted with talcum. If test pieces of the specified thickness are not available (e.g. where they are cut from finished parts), a stack of no more than three sheets of the same material may be used,provided the sheets have parallel surfaces and the same thickness throughout. Test pieces shall not containtextile or other reinforcing material. If the surface is not uniformly smooth, it shall be ground as specified inISO4661-1.NOTE: In the case of thin test pieces, test piece deformation may be influenced by the rigidity of the anvil. Aninternational interlaboratory test using test pieces 6mm and 12mm thick produced differences of 2% to6% in the resilience values, such differences being a function of the hardness of the rubber, and reachinga maximum for very soft rubber. 6.2Number of test pieces  At least two pieces shall be tested. 6.3Conditioning of test pieces Testing shall be carried out not earlier than 16 hours and not later than four weeks after vulcanization. At leastduring the last three hours of this period, the test pieces shall be conditioned at a temperature of (23  t 2)°C.In the case of finished parts, the interval between vulcanization and testing should not exceed three months;otherwise, testing shall commence not later than two months after delivery to the customer. 7Test temperature Testing shall normally be carried out at a temperature of (23  t 1)°C, although test temperatures of –70°C,– 55°C, –40°C, –25°C, –10°C, 0°C, 40°C, 55°C, 70°C, 85°C and 100°C are also acceptable. For testing,test piece, anvil and test piece holder shall be brought to the test temperature, t 1°C, or t 2°C if test tempera-tures are below 0°C (see DINISO471). Page5DIN53512:2000-04The conditioning period is a function of the characteristics of the conditioning device and whether the test pieceis made u of a stack of sheets. The eriod reuired for test ieces 125mm thick and a test temerature of
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