Methods for product accelerated testing

IEC 62506:2013 provides guidance on the application of various accelerated test techniques for measurement or improvement of product reliability. Identification of potential failure modes that could be experienced in the use of a product/item and their mitigation is instrumental to ensure dependability of an item. The object of the methods is to either identify potential design weakness or provide information on item dependability, or to achieve necessary reliability/availability improvement, all within a compressed or accelerated period of time. This standard addresses accelerated testing of non-repairable and repairable systems. It can be used for probability ratio sequential tests, fixed duration tests and reliability improvement/growth tests, where the measure of reliability may differ from the standard probability of failure occurrence. This standard also extends to present accelerated testing or production screening methods that would identify weakness introduced into the product by manufacturing error, which could compromise product dependability. Keywords: test techniques for measurement or improvement of product reliability

Verfahren für beschleunigte Produktprüfungen

Méthodes d'essais accélérés de produits

La CEI 62506:2013 fournit des recommandations pour l'application de diverses techniques d'essais accélérés permettant de mesurer ou d'améliorer la fiabilité des produits. L'identification des modes de défaillance potentiels qui pourraient être rencontrés lors de l'utilisation d'un produit/entité donné(e) et la manière d'y remédier contribuent à assurer la sûreté de fonctionnement d'une entité. L'objectif est soit d'identifier les faiblesses potentielles de la conception et fournir des informations sur la sûreté de fonctionnement de l'entité, soit d'atteindre l'amélioration nécessaire de la fiabilité/disponibilité, dans les deux cas en comprimant ou en accélérant la période d'essai requise. La présente norme couvre les essais accélérés de systèmes non réparables et réparables. Elle peut être utilisée pour des essais progressifs à taux de probabilité, des essais à durée fixe et des essais d'amélioration/croissance de la fiabilité, lorsque la mesure de la fiabilité peut être différente de la probabilité normalisée d'occurrence de défaillance. La présente norme décrit également des méthodes d'essais accélérés ou de déverminage de la production qui permettraient d'identifier les faiblesses induites par une éventuelle erreur de fabrication du produit et qui risqueraient de ce fait d'en compromettre la sûreté de fonctionnement. Mots clés: techniques d'essais permettant de mesurer ou d'améliorer la fiabilité des produits

Metode za pospešeno preskušanje proizvodov (IEC 62506:2013)

Ta mednarodni standard ponuja napotke za uporabo različnih metod za pospešeno preskušanje za ugotavljanje ali izboljšanje zanesljivosti izdelka. Določitev potencialnih zvrsti napak, do katerih lahko pride med uporabo izdelka/dela, in ublažitev le-teh je bistvenega pomena pri zagotavljanju zanesljivosti dela. Cilj metode je določitev morebitnih zasnovnih slabosti, zagotavljanje podatkov o zanesljivosti dela ali izvajanje potrebnih izboljšav zanesljivosti/razpoložljivosti – vse to v strnjenem oz. pospešenem časovnem obdobju. Ta standard obravnava pospešeno preskušanje nepopravljivih in popravljivih sistemov. Uporablja se lahko za sekvenčne preskuse razmerja verjetnosti, preskuse s fiksnim trajanjem in preskuse izboljšanja/povečanja zanesljivosti, pri čemer se lahko stopnja zanesljivosti razlikuje od standardne verjetnosti pojava napake. Ta standard prav tako obravnava trenutno pospešeno preskušanje ali metode za pregled proizvodnje, ki določijo slabosti izdelka, ki so posledica proizvodne napake in ki bi lahko ogrozile zanesljivost izdelka.

General Information

Status
Published
Publication Date
29-Aug-2013
Technical Committee
Drafting Committee
Current Stage
6060 - Document made available
Due Date
30-Aug-2013
Completion Date
30-Aug-2013

Buy Standard

Standard
EN 62506:2014 - BARVE na PDF-strani 19,20,24,25,26,51,52,67,70,87,88,89,91,92
English language
91 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Metode za pospešeno preskušanje proizvodov (IEC 62506:2013)Méthodes d'essais accélérés de produitsMethods for product accelerated testing21.020Characteristics and design of machines, apparatus, equipment19.020Preskuševalni pogoji in postopki na splošnoTest conditions and procedures in general03.120.01Kakovost na splošnoQuality in generalICS:Ta slovenski standard je istoveten z:EN 62506:2013SIST EN 62506:2014en01-maj-2014SIST EN 62506:2014SLOVENSKI

STANDARD
SIST EN 62506:2014
EUROPEAN STANDARD EN 62506 NORME EUROPÉENNE
EUROPÄISCHE NORM August 2013

CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung

CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2013 CENELEC -

All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 62506:2013 E
ICS 03.120.01; 21.020
English version
Methods for product accelerated testing (IEC 62506:2013)
Méthodes d'essais accélérés de produits (CEI 62506:2013)
Verfahren für beschleunigte Produktprüfungen (IEC 62506:2013)

This European Standard was approved by CENELEC on 2013-06-21. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

SIST EN 62506:2014
EN 62506:2013 - 2 -

Foreword The text of document 56/1503/FDIS, future edition 1 of IEC 62506, prepared by IEC/TC 56 "Dependability" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62506:2013.

The following dates are fixed: • latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-03-21 • latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2016-06-21

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 62506:2013 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 60812 NOTE

Harmonized as EN 60812:2006 IEC 61125:1992 NOTE
Harmonized as EN 61125:1993 (not modified).
SIST EN 62506:2014
- 3 - EN 62506:2013
Annex ZA
(normative)

Normative references to international publications with their corresponding European publications

The 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 amendments) applies.

NOTE

When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.

Publication Year Title EN/HD Year IEC 60068
Series Environmental testing - -

IEC 60300-3-1 2003 Dependability management - Part 3-1: Application guide - Analysis techniques for dependability - Guide on methodology EN 60300-3-1 2004

IEC 60300-3-5

Dependability management - Part 3-5: Application guide - Reliability test conditions and statistical test principles - -

IEC 60605-2
Equipment reliability testing -
Part 2: Design of test cycles - -
IEC 60721
Series Classification of environmental testing - -
IEC 61014 2003 Programmes for reliability growth EN 61014 2003
IEC 61124 + corr. January

2012 2013 Reliability testing - Compliance tests for constant failure rate and constant failure intensity EN 61124 2012

IEC 61163-2
Reliability stress screening -
Part 2: Electronic components - -

IEC 61164 2004 Reliability growth - Statistical test and estimation methods EN 61164 2004

IEC 61649 2008 Weibull analysis EN 61649 2008

IEC 61709 2011 Electric components - Reliability - Reference conditions for failure rates and stress models for conversion EN 61709 2011

IEC 61710
Power law model - Goodness-of-fit tests and estimation methods EN 61710
IEC 62303

Radiation protection instrumentation - Equipment for monitoring airborne tritium - -

IEC/TR 62380

Reliability data handbook - Universal model for reliability prediction of electronics components, PCBs and equipment - -

IEC 62429

Reliability growth - Stress testing for early failures in unique complex systems EN 62429

SIST EN 62506:2014
SIST EN 62506:2014

IEC 62506 Edition 1.0 2013-06 INTERNATIONAL STANDARD NORME INTERNATIONALE Methods for product accelerated testing

Méthodes d'essais accélérés de produits

INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE XD ICS 03.120.01; 21.020 PRICE CODE CODE PRIX ISBN 978-2-83220-861-8

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale ®

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé. SIST EN 62506:2014 colourinside

– 2 – 62506 © IEC:2013 CONTENTS FOREWORD ........................................................................................................................... 5 INTRODUCTION ..................................................................................................................... 7 1 Scope ............................................................................................................................... 8 2 Normative references ....................................................................................................... 8 3 Terms, definitions, symbols and abbreviations .................................................................. 9 3.1 Terms and definitions .............................................................................................. 9 3.2 Symbols and abbreviated terms ............................................................................. 11 4 General description of the accelerated test methods....................................................... 12 4.1 Cumulative damage model .................................................................................... 12 4.2 Classification, methods and types of test acceleration ........................................... 14 4.2.1 General ..................................................................................................... 14 4.2.2 Type A: qualitative accelerated tests ......................................................... 15 4.2.3 Type B: quantitative accelerated tests ....................................................... 15 4.2.4 Type C: quantitative time and event compressed tests .............................. 16 5 Accelerated test models ................................................................................................. 17 5.1 Type A, qualitative accelerated tests ..................................................................... 17 5.1.1 Highly accelerated limit tests (HALT) ......................................................... 17 5.1.2 Highly accelerated stress test (HAST) ....................................................... 21 5.1.3 Highly accelerated stress screening/audit (HASS/HASA) ........................... 21 5.1.4 Engineering aspects of HALT and HASS ................................................... 22 5.2 Type B and C – Quantitative accelerated test methods .......................................... 23 5.2.1 Purpose of quantitative accelerated testing ............................................... 23 5.2.2 Physical basis for the quantitative accelerated Type B test methods .......... 23 5.2.3 Type C tests, time (C1) and event (C2) compression ................................. 24 5.3 Failure mechanisms and test design ...................................................................... 26 5.4 Determination of stress levels, profiles and combinations in use and test – stress modelling .................................................................................................... 27 5.4.1 General ..................................................................................................... 27 5.4.2 Step-by-step procedure ............................................................................. 27 5.5 Multiple stress acceleration methodology – Type B tests ....................................... 27 5.6 Single and multiple stress acceleration for Type B tests ........................................ 30 5.6.1 Single stress acceleration methodology ..................................................... 30 5.6.2 Stress models with stress varying as a function of time – Type B tests .......................................................................................................... 37 5.6.3 Stress models that depend on repetition of stress applications – Fatigue models .......................................................................................... 38 5.6.4 Other acceleration models – Time and event compression......................... 40 5.7 Acceleration of quantitative reliability tests ............................................................ 40 5.7.1 Reliability requirements, goals, and use profile .......................................... 40 5.7.2 Reliability demonstration or life tests ......................................................... 42 5.7.3 Testing of components for a reliability measure ......................................... 47 5.7.4 Reliability measures for components and systems/items ............................ 48 5.8 Accelerated reliability compliance or evaluation tests ............................................ 48 5.9 Accelerated reliability growth testing ..................................................................... 50 5.10 Guidelines for accelerated testing ......................................................................... 50 5.10.1 Accelerated testing for multiple stresses and the known use profile ........... 50 5.10.2 Level of accelerated stresses .................................................................... 51 SIST EN 62506:2014

62506 © IEC:2013 – 3 – 5.10.3 Accelerated reliability and verification tests ............................................... 51 6 Accelerated testing strategy in product development ...................................................... 51 6.1 Accelerated testing sampling plan ......................................................................... 51 6.2 General discussion about test stresses and durations ........................................... 52 6.3 Testing components for multiple stresses .............................................................. 53 6.4 Accelerated testing of assemblies ......................................................................... 53 6.5 Accelerated testing of systems .............................................................................. 53 6.6 Analysis of test results .......................................................................................... 53 7 Limitations of accelerated testing methodology ............................................................... 53 Annex A (informative)

Highly accelerated limit test (HALT) .................................................. 55 Annex B (informative)

Accelerated reliability compliance and growth test design ................. 59 Annex C (informative)

Comparison between HALT and conventional accelerated testing .................................................................................................................................. 74 Annex D (informative)

Estimating the activation energy, Ea.................................................. 75 Annex E (informative)

Calibrated accelerated life testing (CALT) ......................................... 77 Annex F (informative)

Example on how to estimate empirical factors ................................... 79 Annex G (informative)

Determination of acceleration factors by testing to failure ................. 84 Bibliography .......................................................................................................................... 87

Figure 1 – Probability density functions (PDF) for cumulative damage, degradation, and test types ....................................................................................................................... 13 Figure 2 – Relationship of PDFs of the product strength vs. load in use ................................ 18 Figure 3 – How uncertainty of load and strength affects the test policy ................................. 19 Figure 4 – PDFs of operating and destruct limits as a function of applied stress ................... 20 Figure 5 – Line plot for Arrhenius reaction model .................................................................. 34 Figure 6 – Plot for determination of the activation energy ...................................................... 35 Figure 7 – Multiplier of the test stress duration for demonstration of required reliability for compliance or reliability growth testing ............................................................................ 45 Figure 8 – Multiplier of the duration of the load application

for the desired reliability ............ 46 Figure B.1 – Reliability as a function of multiplier k and for combinations of parameters a and b .................................................................................................................................. 61 Figure B.2 – Determination of the multiplier k ........................................................................ 64 Figure B.3 – Determination of the growth rate ....................................................................... 73 Figure D.1 – Plotting failures to estimate the activation energy Ea ........................................ 76 Figure F.1 – Weibull graphical data analysis ......................................................................... 81 Figure F.2 – Scale parameter as a function of the temperature range ................................... 82 Figure F.3 – Probability of failure as a function of number of cycles ∆T = 50 °C .................... 83 Figure G.1 – Weibull plot of the three data sets .................................................................... 85 Figure G.2 – Scale parameters’ values fitted with a power line .............................................. 86

Table 1 – Test types mapped to the product development cycle ............................................ 14 Table A.1 – Summary of HALT test results for a DC/DC converter ........................................ 56 Table A.2 – Summary of HALT results from a medical system ............................................... 57 Table A.3 – Summary of HALT results for a Hi-Fi equipment ................................................. 58 Table B.1 – Environmental stress conditions of an automotive electronic device ................... 63 SIST EN 62506:2014

– 4 – 62506 © IEC:2013 Table B.2 – Product use parameters ..................................................................................... 67 Table B.3 – Assumed product use profile .............................................................................. 71 Table B.4 – Worksheet for determination of use times to failures .......................................... 72 Table B.5 – Data for reliability growth plotting ....................................................................... 73 Table C.1 – Comparison between HALT and conventional accelerated testing ...................... 74 Table F.1 − Probability of failure of test samples A and B ..................................................... 80 Table F.2 – Data transformation for Weibull plotting .............................................................. 80 Table G.1 – Voltage test failure data for Weibull distribution ................................................. 84

SIST EN 62506:2014
62506 © IEC:2013 – 5 – INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
METHODS FOR PRODUCT ACCELERATED TESTING

FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 62506 has been prepared by IEC technical committee 56: Dependability. The text of this standard is based on the following documents: FDIS Report on voting 56/1503/FDIS 56/1513/RVD

Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. SIST EN 62506:2014

– 6 – 62506 © IEC:2013 The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be • reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer.

SIST EN 62506:2014

62506 © IEC:2013 – 7 – INTRODUCTION Many reliability or failure investigation test methods have been developed and most of them are currently in use. These methods are used to either determine product reliability or to identify potential product failure modes, and have been considered effective as demonstrations of reliability: – fixed duration,

– sequential probability ratio,
– reliability growth tests,
– tests to failure, etc.

Such tests, although very useful, are usually lengthy, especially when the product reliability that has to be demonstrated was high. The reduction in time-to-market periods as well as competitive product cost, increase the need for efficient and effective accelerated testing. Here, the tests are shortened through the application of increased stress levels or by increasing the speed of application of repetitive stresses, thus facilitating a quicker assessment and growth of product reliability through failure mode discovery and mitigation. There are two distinctly different approaches to reliability activities: – the first approach verifies, through analysis and testing, that there are no potential failure modes in the product that are likely to be activated during the expected life time of the product under the expected operating conditions;

– the second approach estimates how many failures can be expected after a given time under the expected operating conditions.

Accelerated testing is a method appropriate for both cases, but used quite differently. The first approach is associated with qualitative accelerated testing, where the goal is identification of potential faults that eventually might result in product field failures. The second approach is associated with quantitative accelerated testing where the product reliability may be estimated based on the results of accelerated simulation testing that can be related back to the use of the environment and usage profile. Accelerated testing can be applied to multiple levels of items containing hardware or software. Different types of reliability testing, such as fixed duration, sequential test-to-failure, success test, reliability demonstration, or reliability growth/improvement tests can be candidates for accelerated methods. This standard provides guidance on selected, commonly used accelerated test types. This standard should be used in conjunction with statistical test plan standards such as IEC 61123, IEC 61124, IEC 61649 and IEC 61710. The relative merits of various methods and their individual or combined applicability in evaluating a given system or item, should be reviewed by the product design team (including dependability engineering) prior to selection of a specific test method or a combination of methods. For each method, consideration should also be given to the test time, results produced, credibility of the results, data required to perform meaningful analysis, life cycle cost impact, complexity of analysis and other identified factors.

SIST EN 62506:2014
– 8 – 62506 © IEC:2013 METHODS FOR PRODUCT ACCELERATED TESTING

1 Scope This International Standard provides guidance on the application of various accelerated test techniques for measurement or improvement of product reliability. Identification of potential failure modes that could be experienced in the use of a product/item and their mitigation is instrumental to ensure dependability of an item.

The object of the methods is to either identify potential design weakness or provide information on item dependability, or to achieve necessary reliability/availability improvement, all within a compressed or accelerated period of time. This standard addresses accelerated testing of non-repairable and repairable systems. It can be used for probability ratio sequential tests, fixed duration tests and reliability improvement/growth tests, where the measure of reliability may differ from the standard probability of failure occurrence.

This standard also extends to present accelerated testing or production screening methods that would identify weakness introduced into the product by manufacturing error, which could compromise product dependability. 2 Normative references The 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 amendments) applies. IEC 60068 (all parts), Environmental testing IEC 60300-3-1:2003, Dependability management – Part 3-1: Application guide – Analysis techniques for dependability – Guide on methodology IEC 60300-3-5, Dependability management – Part 3-5: Application guide – Reliability test conditions and statistical test principles IEC 60605-2, Equipment reliability testing – Part 2: Design of test cycles IEC 60721 (all parts), Classification of environmental conditions IEC 61014:2003, Programmes for reliability growth IEC 61164:2004, Reliability growth – Statistical test and estimation methods IEC 61124:2012, Reliability testing – Compliance tests for constant failure rate and constant failure intensity

IEC 61163-2, Reliability stress screening – Part 2: Electronic components IEC 61649:2008, Weibull analysis

IEC 61709, Electronic components – Reliability – Reference conditions for failure rates and stress models for conversion SIST EN 62506:2014

62506 © IEC:2013 – 9 – IEC 61710, Power law model – Goodness-of-fit tests and estimation methods IEC 62303, Radiation protection instrumentation – Equipment for monitoring airborne tritium

IEC/TR 62380, Reliability data handbook – Universal model for reliability prediction of electronics components, PCBs and equipment IEC 62429, Reliability growth – Stress testing for early failures in unique complex systems

3 Terms, definitions, symbols and abbreviations For the purposes of this document, the term and definitions given in IEC 60050-191:____, as well as the following, apply. NOTE Symbols for reliability, availability, maintainability and safety measures follow those of

IEC 50060-191:1990, where available.
3.1 Terms and definitions 3.1.1

item subject being considered Note 1 to entry: The item may be an individual part, component, device, functional unit, equipment, subsystem, or system.

Note 2 to entry: The item may consist of hardware, software, people or any combination thereof.

Note 3 to entry: The item is often comprised of elements that may each be individually considered. See "sub-item", definition 191-41-02 and "indenture level", definition 191-41-05.

Note 4 to entry: IEC 60050-191:1990, first edition, identified the term “entity” as a synonym, which is not true for all applications.

Note 5 to entry: The definition for item given in the first edition

is a description rather than a definition. This new definition provides meaningful substitution throughout this standard. The words of the former definition form the new note 1. [SOURCE: IEC 60050-191:—, definition 191-41-01] [1]1 3.1.2

step stress step stress test

test in which the applied stress is increased, after each specified interval, until failure occurs or a predetermined stress level is reached

Note 1 to entry: The ‘intervals’ could be specified in terms of number of stress applications, durations, or test sequences.

Note 2 to entry: The test should not alter the basic failure modes, failure mechanisms, or their relative prevalence. [SOURCE: IEC 60050-191:—, definition 191-49-10] 3.1.3

acceleration factor ratio between the item failure distribution characteristics or reliability measures (e.g. failure intensities) of an item when it is subject to stresses in expected use and those the item acquires when the higher level stresses are applied for achieving a shorter test duration ————————— 1

Figures in square brackets refer to the Bibliography. SIST EN 62506:2014

– 10 – 62506 © IEC:2013 Note 1 to entry: For a test to be effectively accelerated, the acceleration factor is ξ1. Note 2 to entry: When the failure distribution Poisson is assumed with constant failure rate, then the acceleration factor corresponds to the ratio of time under stress in use vs. time under increased stress in test. 3.1.4

highly accelerated limit test HALT test or sequence of tests intended to identify the most likely failure modes of the product in a defined stress environment

Note 1 to en
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.