1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18312-2:2012Mechanical vibration and shock Measurement of vibrationpower flow from machines intoconnected support structuresPart 2: Indirect methodBS ISO 18312-2:2012 BRIT
2、ISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18312-2:2012.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
3、 list 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 Standards
4、Limited 2012ISBN 978 0 580 55235 9ICS 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 I
5、SO 18312-2:2012 ISO 2012Mechanical vibration and shock Measurement of vibration power flow from machines into connected support structures Part 2: Indirect methodVibrations et chocs mcaniques Mesurage du flux de puissance vibratoire transmis par des machines aux structures de support dont elles sont
6、 solidaires Partie 2: Mthode indirecteINTERNATIONAL STANDARDISO18312-2First edition2012-01-15Reference numberISO 18312-2:2012(E)BS ISO 18312-2:2012ISO 18312-2:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this p
7、ublication 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 Gen
8、eva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18312-2:2012ISO 18312-2:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Terms and definitions . 14 Fundamentals . 44.1 General ma
9、terial for determination of emitted vibration power . 44.2 Expression of vibration power in different forms . 75 Measurement 85.1 Vibration transducers arrangement . 85.2 Typical signal processing for evaluation of acceleration cross-spectrum 115.3 Metrological specifications . 116 Test procedures .
10、126.1 Choice of number of vibration isolators to measure from .126.2 Transducer placement and determination of maximum frequency .127 Measurement uncertainty .138 Data presentation and test report .13Annex A (informative) Construction of dynamic stiffness matrix of vibration isolators .15Annex B (in
11、formative) Examples of simple geometries and linear components of dynamic stiffness matrix for massless isolators .16Bibliography .18BS ISO 18312-2:2012ISO 18312-2:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO memb
12、er bodies). The work 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, government
13、al and non-governmental, 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 Directi
14、ves, Part 2.The main 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
15、casting a vote.Attention 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 18312-2 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock
16、 and condition monitoring.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 18312-2:
17、2012INTERNATIONAL STANDARD ISO 18312-2:2012(E)Mechanical vibration and shock Measurement of vibration power flow from machines into connected support structures Part 2: Indirect method1 ScopeThis part of ISO 18312 specifies a method for evaluating the vibration power emitted by machines or pipelines
18、 (referred to hereinafter as machines) on to supporting structures to which the machines are connected through vibration isolators. This part of ISO 18312 also specifies the method for evaluating the vibration power components emitted in the six degrees of freedom of a Cartesian coordinate system at
19、 each joint, i.e. three translations and three rotations. The vibration power is determined by processing the signals from two sets of velocity (or acceleration) transducers mounted at the isolator connection points, one set on the machine side (input) and the other on the foundation side (output).
20、This method is applicable for machines under the assumption that their vibration can be characterized by a stationary random process.The components of emitted vibration power are computed using the cross-spectra of the two sets of velocity in narrow band (or one third-octave) and the dynamic stiffne
21、ss characteristics of the isolator over the frequency range of interest.The upper frequency limits of this method are established in this part of ISO 18312.This part of ISO 18312 can be used for:a) evaluating a machinery system from isolator design concept;b) obtaining data for preparation of techni
22、cal requirements for allowable machine vibration power emission;c) determining appropriate and cost-effective vibration control procedures;d) solving diagnostics issues.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensab
23、le for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 2041, Mechanical vibration, shock and condition monitoring VocabularyISO 5348, Mechanical vibration and shock Mec
24、hanical mounting of accelerometersISO 10846-1, Acoustics and vibration Laboratory measurement of vibro-acoustic transfer properties of resilient elements Part 1: Principles and guidelines3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 2041 and the fol
25、lowing apply. ISO 2012 All rights reserved 1BS ISO 18312-2:2012ISO 18312-2:2012(E)3.1velocity vectorvn,mvibration velocity vector at the nth isolator on a machine, consisting of three translational and three rotational components along the coordinate axes x, y, and zNote to entry: The symbol vn,fden
26、otes velocity vector at the same isolator on a foundation.3.2velocity componentvin,mcomponent of vibration velocity vector in the degree of freedom i at the nth isolator on the machine; i = 1, 2, and 3 for the linear components in the x-, y-, and z-directions, respectively, and i = 4, 5, and 6 for a
27、ngular components in the x-, y-, and z-directions, respectivelyNote to entry: The symbol vin,frepresents vibration velocities at the same isolator on the foundation.3.3acceleration componentain,mcomponent of vibration acceleration in the degree of freedom i at the nth isolator on the machine3.4root
28、mean square value of acceleration componentr.m.s. value of acceleration componentain:rms,mroot mean square value of the vibration acceleration component in the degree of freedom i at the nth isolator on the machine3.5force vectorFn,mindirect method vibration force vector acting at the nth isolator b
29、y the machine, consisting of three linear force components and three angular force components or moments, along the coordinate axes x, y, and zNote to entry: The symbol Fn,frepresents a force vector acting at the same isolator by the foundation, which becomes the same as -Fn,mif the vibration isolat
30、ors are massless.3.6force componentFin,mindirect method component of vibration force vector in the degree of freedom i at the nth isolator on the machine; i = 1, 2, and 3 for force components in the x-, y-, and z-directions, respectively, and i = 4, 5, and 6 for the moment components in the x-, y-,
31、and z-directions, respectively3.7vibration power componentPin,mindirect method vibration power component emitted from the machine into the nth isolator in the degree of freedom i, given by time average of scalar product of force vector and velocity vector at the nth isolator on the machine in the de
32、gree of freedom iNote to entry 1: A vibration power component is expressed in watts.Note to entry 2: The symbol Pin,frepresents vibration power components transmitted into foundation via the nth isolator.2 ISO 2012 All rights reservedBS ISO 18312-2:2012ISO 18312-2:2012(E)3.8vibration power at a moun
33、tPn,msum of vibration power emitted from the machine into the nth isolator over all degrees of freedomNote to entry: The symbol Pn,frepresents vibration power transmitted into the foundation via the same isolator.3.9vibration powerPmindirect method total vibration power emitted from the machine into
34、 the isolators, given by the sum of vibration power emitted from the machine over all isolators and in every degree of freedomNote to entry: The symbol Pfrepresents total power transmitted into the foundation via all isolators.3.10vibration power spectrumPm(f, f)indirect method decomposition of the
35、total vibration power from the machine Pminto frequency domain with a given centre frequency f and bandwidth f3.11component of vibration power spectrumPffin,m, ()indirect method spectrum of vibration power emitted from the machine in the degree of freedom i at the nth isolator3.12vibration power spe
36、ctrum at an isolatorPn,m(f, f)spectrum of the vibration power emitted from the machine at the nth joint3.13velocity cross-spectrumGffvvjnin,m ,f,()cross-spectrum of the vibration velocity vjnt,m() at the nth isolator in the degree of freedom j on the machine as the input and vibration velocity vint,
37、f() in the degree of freedom i on the foundation as the outputNote to entry: Velocity cross-spectrum is expressed in metres per second squared.3.14vibration power levelLWLPPW=100lg dBten times the logarithm to the base 10 of the ratio of the measured vibration power, P, to a reference value, P0= 1 p
38、W, expressed in decibels3.15input dynamic stiffness matrix of vibration isolatorKnf,in()matrix of frequency-dependent complex dynamic stiffness of the nth vibration isolator at the input or machine3.16output dynamic stiffness matrix of vibration isolatorKnf,out()matrix of frequency-dependent complex
39、 dynamic stiffness of the nth vibration isolator at the output or foundation ISO 2012 All rights reserved 3BS ISO 18312-2:2012ISO 18312-2:2012(E)3.17transfer dynamic stiffness matrix of vibration isolatorKnf,tr()matrix of frequency-dependent complex dynamic stiffness across the nth vibration isolato
40、r between the machine and foundation4 Fundamentals4.1 General material for determination of emitted vibration powerFigure 1 shows a schematic diagram of a machine mounted on N vibration isolators and then attached to a foundation structure, where the coordinates for the machine apply to the vibratio
41、n isolators as well as to the foundation under the assumption that rotational motions of the machine are small.Figure 2 shows designations for the measurements of force, moment, linear velocity, and angular velocity at the nth joint on the input or machine and output or the foundation, where moments
42、 and angular velocities are defined as positive in the clockwise direction when looking along the axes from the coordinate origin.Key1 machine2 isolator3 foundationFigure 1 Diagram of machine on foundation via multiple isolators and coordinate systems4 ISO 2012 All rights reservedBS ISO 18312-2:2012
43、ISO 18312-2:2012(E)Key1 input (by machine)2 nth vibration isolator3 output (by foundation)Figure 2 Coordinate systems for input (machine) and output (foundation) measurements of an nth isolator and designation of force, F, moment, M, linear, v, and angular, w, velocity componentsVibration power tran
44、smitted into the foundation at the nth vibration isolator is defined as the time average of the scalar product of force vector Fn,f(t) and velocity vector vn,f(t) at the nth isolator on the foundation as follows:PLtttLFtvttnnnLininiL,f ,f ,f0,f ,f60dd= () () = () () =11 11FvLFtvttininLi,f ,f06d() ()
45、= 1(1)where L is the duration for time averaging and1LFtvttPininLin,f ,f0,fd() () represents the vibration power transmitted into the foundation in the degree of freedom i via the nth isolator. The total vibration power into the foundation via N mounts is given simply by a sum of the vibration power
46、 on to the foundation via each mount as follows: ISO 2012 All rights reserved 5BS ISO 18312-2:2012ISO 18312-2:2012(E)PPnnNf,f=1=(2)Decomposition of the vibration power at the nth isolator in the degree of freedom i, Pin,f, into the frequency domain is described by the vibration power spectrum with a
47、 given frequency bandwidth f, Pffin,f,(), which can be obtained from the real part of the cross-spectrum of the stationary random processes of the force Fin,fand velocity vin,fas follows:PffGffinFvnii,f ,fRe,()= ()(3)Similarly, the spectrum of the vibration power emitted from the machine at the nth
48、isolator in the degree of freedom i can be expressed as follows:PffGffinFvnii,m ,mRe,()= ()(4)The relationship between operational random vibration forces on to the isolator Fn,macting from the machine and those on to the isolator Fn,freacting from the foundation and corresponding random vibration v
49、elocities at the machine and foundation, vn,mand vn,f, respectively, are represented as follows:FKvK vFnnnnffff fff,f ,tr,m,out ,f,mj2()= () () () ()()1pinn+= () ()+ () ()1j2,in,m,tr ,fpifff ffnnKv Kv(5)where Kn,trrepresents the blocked transfer dynamic stiffness matrix of the nth isolator between the output where the foundation is connected and the input where the machine is connected, Kn,outthe driving point dynamic stiffness matrix at the output when the input side is blo
