IEC 62506:2013

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

Méthodes d'essais accélérés de produits

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

Méthodes d'essais accélérés de produits

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

– 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 (C ) and event (C ) compression . 24
1 2
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

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, E . 75
a
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 E . 76
a
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 .
...