BS 5760-16.1:1996

Committees responsible
National foreword
Introduction
Guide
1 Scope
2 Normative references
3 Definitions
4 Symbols
5 General description
6 Planning
7 Pilot-production screening
8 Mature production screening
Annexes
A (informative) Stress conditions: general information
B (informative) Stress conditions: temperature
C (informative) Stress conditions: vibration and bump
D (informative) Stress conditions: humidity
E (informative) Stress conditions: operational stress
F (informative) Bimodal distributions - Weibull
     plotting and analysis
G (informative) Evaluation of the failure-free
     period and the average screening duration
H (informative) Worked-through example
Tables
A.1 Stress types - indication of cost of application
H.1 Relations between the sensitivity of flaws and
     stresses
H.2 Observed failure ranks and times to first failure
     for the pilot production
H.3 Revised rank values
Figures
1 The conceptual difference between reliability
     screening and growth
2 Typical flow for the design and modifications of
     reliability stress screening processes for
     repairable items
3 A typical flow of hardward items from the component
     manufacturer to the end user
4 Reliability stress screening of repairable items
5 Dependency of categories of failures
6 Elements of stress conditioning
7 The item must show a failure-free period Tm before
     being accepted
8 Time graphs for determination of the failure-free
     period
F.1 The S-curve for a bimodal Weibull distribution
     mixed by
     F1(t)=1-e (t/30) 1,5 and F2(t)=1-e (t/60 000) 1,5
F,2 Estimation of p, k1 and b1 for the purpose of
     reliability screening optimization
F.3 The c.d.f's for bimodal exponential distributions
F.4 The hazard rate function for bimodal exponential
     distributions
G.1 The basic system
G.2 An item with n weak components surviving the
     screening period TM
G.3 Possible states, when a component fails during the
     stress screening
G.4 Item states after failure and repair
G.5 Time graph for evaluation of the failure-free
     screening period
G.6 Average screening duration versus the normalized
     failure-free period TM/mF1
H.1 Derivation of the failure-free period TM
H.2 Derivation of the average screening duration
H.3 Observed figure pattern and predicted curve for
     the pilot production
H.4 Pilot production screening plot of relevant
     failures and predicted S-curve for the sole failures
     taken into account
H.5 Time graph (corrected) for determination of the
     failure-free period
H.6 Time graph (corrected) for evaluation of the
     screening duration

Describes particular methods to apply and optimise reliability stress screening processes for lots of repairable hardware items. Applies where the items have an unacceptably low reliability in the early failure period, and where other methods are not applicable.