1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18312-1:2012Mechanical vibration and shock Measurement of vibrationpower flow from machines intoconnected support structuresPart 1: Direct methodBS ISO 18312-1:2012 BRITIS
2、H STANDARDNational forewordThis British Standard is the UK implementation of ISO 18312-1:2012.The UK participation in its preparation was entrusted to TechnicalCommittee GME/21/2, Mechanical vibration, shock and conditionmonitoring - Vibration and shock measuring instruments and testingequipment.A l
3、ist of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLi
4、mited 2012ISBN 978 0 580 55234 2ICS 17.160Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 March 2012.Amendments issued since publicationDate Text affectedBS ISO
5、 18312-1:2012 ISO 2012Mechanical vibration and shock Measurement of vibration power flow from machines into connected support structuresPart 1: Direct methodVibrations et chocs mcaniques Mesurage du flux de puissance vibratoire transmis par des machines aux structures de support dont elles sont soli
6、daires Partie 1: Mthode directeINTERNATIONAL STANDARDISO 18312-1First edition 2012-01-15Reference number ISO 18312-1:2012(E)BS ISO 18312-1:2012ISO 18312-1:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publi
7、cation may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva
8、20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18312-1:2012ISO 18312-1:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Terms and definitions . 14 Fundamentals . 35 Measurement 55.1
9、 General . 55.2 Arrangement of vibration transducers 55.3 Measurement of forces 55.4 Measurement equipment . 75.5 Metrological specifications . 85.6 Determination of upper frequency limit 95.7 Choice of number of joints to measure from . 95.8 Determination of total vibration power by measuring from
10、a limited number of joints . 96 Measurement uncertainty .107 Data presentation and test report .10Bibliography .12BS ISO 18312-1:2012ISO 18312-1:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The wor
11、k of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governme
12、ntal, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The mai
13、n task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.Atte
14、ntion is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 18312-1 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition moni
15、toring.ISO 18312 consists of the following parts, under the general title Mechanical vibration and shock Measurement of vibration power flow from machines into connected support structures: Part 1: Direct method Part 2: Indirect methodiv ISO 2012 All rights reservedBS ISO 18312-1:2012INTERNATIONAL S
16、TANDARD ISO 18312-1:2012(E)Mechanical vibration and shock Measurement of vibration power flow from machines into connected support structures Part 1: Direct method1 ScopeThis part of ISO 18312 specifies a method for evaluating the vibration power emitted by machines or pipelines, referred to hereina
17、fter as machines, under operational conditions on to supporting structures to which the machines are directly connected via bolted joints. This part of ISO 18312 specifies the method for evaluating the vibration power components emitted in the six degrees of freedom of a Cartesian coordinate system
18、at each joint, i.e. three translations and three rotations. The vibration power is determined by processing the signals from force and velocity (or acceleration) transducers mounted on to the bolted joints under operational conditions of interest. This method is applicable for machines under the ass
19、umption that their vibration can be characterized by a stationary random process.The components of emitted vibration power in the frequency domain are obtained by computing the cross-spectrum of the force and velocity measurement pairs with a given narrow band width at each bolted joint.This direct
20、method assumes that the supporting structures are adequately rigid and, hence, it is not applicable to cases where the foundation or supporting structures are resilient, which will potentially go into a state of resonance within the frequency range of interest. Practical frequency limits of the meth
21、od are specified in this part of ISO 18312.This part of ISO 18312 can be used in operational conditions for:a) specification of vibration power emission of machines at the (bolted) joints;b) identification of vibration power severity;c) resolving diagnostics issues;d) planning vibration control meas
22、ures.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any a
23、mendments) applies.ISO 2041, Mechanical vibration, shock and condition monitoring VocabularyISO 5348, Mechanical vibration and shock Mechanical mounting of accelerometers3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 2041 and the following apply.3.1v
24、ibration velocity vectorvnvelocity vector at the nth bolt joint, consisting of three translational and three rotational components along the coordinate axes x, y and z ISO 2012 All rights reserved 1BS ISO 18312-1:2012ISO 18312-1:2012(E)3.2vibration velocity componentvincomponent of the vibration vel
25、ocity vector in the degree of freedom i at the nth bolted joint; i = 1, 2 and 3 for linear components in the x-, y-, and z-directions, respectively, and i = 4, 5 and 6 for angular components in the x-, y- and z-directions, respectively3.3vibration acceleration componentainvibration acceleration comp
26、onent in the degree of freedom i at the nth bolted joint3.4root mean square value of acceleration componentr.m.s. value of acceleration componentain:rmsroot mean square value of the vibration acceleration component in the degree of freedom i at the nth bolted joint3.5force vectorFnvibration force ve
27、ctor at the nth joint, consisting of three components of linear force and three components of angular force, i.e. moment, along the coordinate axes x, y and z3.6force componentFincomponent of the vibration force vector in the degree of freedom i at the nth joint; i = 1, 2 and 3 for force components
28、in the x-, y- and z-directions, respectively, and i = 4, 5 and 6 for moment components in the x-, y- and z-directions, respectively3.7vibration power componentPinvibration power in the degree of freedom i at the nth bolted joint, equal to the time-averaged scalar product of the vibration force vecto
29、r and vibration velocity vector in the degree of freedom i at the nth bolted jointNote to entry: A vibration power component is expressed in watts.3.8vibration power at a jointPnvibration power at the nth bolted joint, equal to the sum of the vibration power components in each degree of freedom at t
30、hat point3.9vibration powerPsum of vibration power of the machine over all joints and in every degree of freedom3.10vibration power spectrumP(f, f)decomposition of the vibration power of the machine into frequency domain with a given centre frequency, f, narrow frequency band, f, equal to the sum of
31、 the vibration power spectra over all joints and in every degree of freedom2 ISO 2012 All rights reservedBS ISO 18312-1:2012ISO 18312-1:2012(E)3.11component of vibration power spectrumPffin,()spectrum of the vibration power transmitted in the degree of freedom i at the nth joint3.12vibration power s
32、pectrum at a joint nPffn,()spectrum of the vibration power transmitted at the nth joint3.13component of vibration power cross spectrumGfFvnii()cross spectrum of a vibration force component, Fi(t), and a vibration velocity component, vi(t), in the degree of freedom i at the nth joint3.14vibration pow
33、er levelLPPW=100lg dBcommon logarithm of the ratio of measured vibration power to the reference value, P0= 1 pW, corresponding to zero level of vibration power4 FundamentalsThe layout of a machine bolted directly on to the foundation structure at multiple joints is shown in Figure 1 and the detail o
34、f a bolted joint is shown in Figure 2 together with a coordinate system, where the z-axis is chosen in parallel with the bolt axis.Key1 machine2 bolted joints3 foundationFigure 1 Layout of machine bolted on to foundation directly at multiple joints ISO 2012 All rights reserved 3BS ISO 18312-1:2012IS
35、O 18312-1:2012(E)Key1 machine leg2 bolt3 nut4 foundation flangeFigure 2 Coordinate system of a bolted jointVibration power emitted by the machine on to the foundation via the nth bolted joint is defined as the time average of scalar product of the force vector and velocity vector as follows:PLtttLFt
36、vttLFtvnnnLininiLinin= () () = () () = ()=11 10160FvddtttLi()=d016(1)where the term within the summation on the most right hand side10LFtvttPininLin() () ddenotes vibration power emitted in the degree of freedom i at the nth joint with the index i = 1 to 3 denoting the linear or translational degree
37、s of freedom and the index i = 4 to 6 denoting the angular or rotational degrees of freedom. The record length L in Equation (1) shall be far greater than the fundamental period of the measured signals. In practice, contributions of the rotational components in Equation (1) due to angular velocities
38、 and moments may be omitted when difficulty of measurements exists. The total vibration power emitted by a machine with multiple bolted joints on to the support structure can be obtained just by summing up the vibration power transmitted via each bolted joint in Equation (1). Vibration power is a sc
39、alar quantity and, hence, the total vibration power emitted from a machine with a number of bolted joints, K, is given simply by a sum:PPnnK=1(2)The vibration power in the ith degree of freedom at the nth joint, Pin, can be resolved into the frequency domain by taking real parts of the cross power s
40、pectrum GffFvnii,() from the force signal Ftin() and velocity signal vtin() using a commercial signal analyser as follows:PffGffinFvnii,Re,()= ()(3)where Re denotes the real part of a complex quantity and the unit of PffGffinFvnii,Re,()= ()is watt at a centre frequency, f, over a narrow frequency ba
41、nd, f, e.g. 1 Hz when the units of the force and velocity are newton and metre per second, respectively. If acceleration atin() in metre per second squared is measured 4 ISO 2012 All rights reservedBS ISO 18312-1:2012ISO 18312-1:2012(E)instead of the velocity vtin() in metre per second, the vibratio
42、n power in Equation (3) is given in a slightly different format as follows:PfffGffinFanii,Im,pi()= ()12(4)where Im denotes the imaginary part of the complex quantity . The sum of the vibration power over frequencies, degrees of freedom, and all the mounts of interest can now be easily calculated. Wh
43、en a partial vibration power over a specific frequency range of interest, in hertz, e.g. from fminto fmaxis of interest, it can be obtained simply by summing the vibration power spectrum Pffin,() in Equation (3) or (4) as follows:Pf fPfkffininkNminmax min,()=+()=11 (5)where N is the number of freque
44、ncy points over the frequency range of interest given byNfff=maxminin case of a narrow frequency band analysis. Once the vibration power spectrum is available in a narrow band from Equations (3) and (4), the vibration power spectrum over one-third octave band or other octave bands can be obtained by
45、 simply summing over the bandwidths of interest.5 Measurement5.1 GeneralThis part of ISO 18312 specifies how to evaluate the vibration power transmitted by a machine on to its foundation from the measurement of forces and vibration at the bolted joints. Such measurements are not limited to translati
46、onal degrees of freedom, but may be extended to rotational degrees of freedom, depending upon the capabilities of the employed transducers. This clause explains how to install the vibration and force transducers.5.2 Arrangement of vibration transducersOne multi-axial vibration transducer is placed o
47、n a joint bolt head as shown in Figures 3 and 4 such that the directions of measurement are aligned with the x- and z-coordinates described in Figure 2. A flat surface on the machines leg, close to the bolted joint, can also be used if multiple uni-axial transducers are to be placed individually. De
48、tails of mounting shall be in accordance with ISO 5348.5.3 Measurement of forces5.3.1 GeneralThe forces acting through the bolted joints from the machine on to the foundation can be measured by placing one transducer (see Figure 3) or two transducers (see Figure 4) in the bolted joints. In both case
49、s, this part of ISO 18312 assumes the use of integrated triaxial force transducers.There should be no local resonance near the bolting joint for the method of force measurement by inserting the force transducers at the joint to be effective. A torque wrench should be used to maintain the torque with the force transducers inserted at the value without those. ISO 2012 All rights reserved 5BS ISO 18312-1:2012ISO 18312-1:2012(E)Key1 machine leg aiacceleration in the degree of
