ISO INTERNATIONAL STANDARD 18431-4 First edition 2007-02-01 Mechanical vibration and shock Signal processing Part 4: Shock-response spectrum analysis Vibrations et chocs mécaniques - Traitement du signal - Partie 4: Analyse du spectre de reponse aux chocs Reference number ISO 18431-4:2007(E) @ ISO 2007 ISO 18431-4:2007(E) Contents Page Foreword Introduction 1 Scope 2 Normative references . 3 Terms and definitions. 4 Symbolsandabbreviatedterms. 2 5 Shock-response spectrum fundamentals, 6 Shock-response spectrum calculation... 7 Sampling frequency considerations. Is 2007 -All rights reserved ii ISO 18431-4:2007(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies technicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeer 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/lEC Directives, 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 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 18431-4 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition monitoring. processing: Part 1: General introduction Part 2: Time domain windows for Fourier Transform analysis Part 4: Shock-response spectrumanalysis The following parts are under preparation: - a part 3, dealing with bilinear methods for joint time-frequency analysis a part 5, dealing with methods for time-scale analysis iv @ ISO 2007 - All rights reserved ISO 18431-4:2007(E) Introduction In the recent past, nearly all data analysis has been accomplished through mathematical operations on acquisition systems and computerized data processing equipment. The analysis of data is, therefore, primarily a digital signal-processing task. The analysis of experimental vibration and shock data should be thought of as a part of the process o experimental mechanicsthat includes all steps from experimental designthroughdata evaluation and understanding. IsO 18431 (all parts) assumes that the data have been sufficiently reduced so that the effects of instrument time samples of acceleration describing vibration or shock. Experimental methods for obtaining the data are outside the scope of IsO 18431 (all parts). The analysis is by no means restricted to signals that can be characterized as shocks. On the contrary, it is, in characterized by its time integral, the impulse, corresponding to constant frequency content. The notation "shock-response spectrum" has been kept, however, although a better term would be maximum-response spectrum. Historically, the shock-response spectrum was initially used to describe transient phenomena, at the time called shocks. Response analysis in general is a method to characterize a vibration or shock when other frequency analysis methods are inadequate.Thiscanbethecase,forinstance,whendifferentkindsof vibrationare compared analyzed are of different kinds, such as periodic, random or transient. The typical use of a shock-response spectrum is to characterize a dynamic mechanical environment. The vibration (or shock) characterized is recorded in digital form, commonly as acceleration. The data are is reguired to endurethe environment in question.There exist International Standards that describehowto design tests from given shock-response spectrum specifications, for example IEC 60068-2-81. (See the bibl