Tool centered Safety Design Support

Transcription

1 Tool centered Safety Design Support Stephan Aschenbrenner exida.com GmbH Tel:

2 About myself Stephan H. Aschenbrenner, CFSE Dipl. Ing. (Univ) for Electrical Engineering and Automation of the Technical University of Munich (TUM) Start as a software and hardware developer of programmable electronic systems At TÜV Product Service GmbH responsible for machinery safety components later at TÜV Product Service Inc. in the USA responsible for setting up a functional safety department for the Americas Business Unit Manager at TÜV Product Service Since 2001 at exida.com GmbH involved in both product analysis and design process improvements in the process industry, the machinery industry, as well as in the automotive and semiconductor industry Responsible for exida s FMEDA tool SILcal Since 2007 Certified Functional Safety Expert (CFSE) Since 2013 Operational Manager at exida.com GmbH Over twenty years of experience and extensive knowledge in the safety and reliability field 2

3 Quellen von Ausfallraten FUNKTIONALE SICHERHEIT UND IT-SICHERHEIT 2017 Kaisersaal Erfurt März /10/2017 Copyright exida.com

4 Warum benötigen wir Ausfallraten? IEC (SIL) ISO (PL) PFD PFH SFF MTTF d DC Random hardware failure rate calculate classified failure rates calculate FMEDA Failure rate λ, failure modes, failure mode distribution 4

5 What determines Achieved SIL? Equipment Design Conceptual Design Diagnostics Failure rate Failure Modes Proof Test Frequency SFF HFT IEC capability SIL AC SIL CAP Minimum Achieved SIL SIL PFD 5

6 Getting Failure Data Industry Databases Manufacturer Field Return Data Studies B 10 Data End User Field Failure Data Studies 6

7 Industry Databases Good base for comparison reasons. Often not applicable for all industries Often not updated anymore. Lots of parameters which are often unknown or not available. Use of parameters is not harmonized. 7

8 Manufacturer Field Return Data Studies Manufacturer Field Return Data Studies PLUS: Real Data MINUS: Cannot know what percentage of actual failures are returned Different definitions of FAILURE (Not a problem scenario) Many manufacturers classify returned items as a failure only if a manufacturing defect is found. Many returned items are marked no problem found. In some calculations operational hours are estimated based on shipping records and it is assumed that all failures are returned. The data can be valuable to identify root causes and compare to establish upper/lower bounds on failure rates. 8

9 B10 Data B 10 data is derived from a cycle test of a mechanical / electromechanical product. Failure rate is calculated based on 10% failures in time period. B 10d (dangerous failure rate) is half that number based on the assumption that 50% of the failures are dangerous. B 10 data is used for high demand mode applications. Not suitable for all uses of failure rate information. The B 10 method assumes that the constant failure rate during the useful life is due to premature wear-out where other failure modes are insignificant. Research shows other failure modes become significant when these products do not move frequently some failure modes become significant if a product is static for 24 hours. 9

10 End User Field Failure Data Studies PLUS: Field failure studies with sufficient information represent a rich opportunity to obtain failure rate and failure mode information about a product in a specific application. MINUS: Variations in the amount of collected data Different definitions of FAILURE Categorizing and Merging Technologies After performing dozens of studies exida experience recognized that the data collection process varies by an order of magnitude or more! When is a failure report written? What is the definition of failure? Are "as found" conditions recorded during a proof test? What were the operating conditions? Use of new data collection software can improve failure data availability 10

11 Source of industry databases failure rates SN IEC Ed.1 /TR (formerly known as UTE C ) FIDES Guide 2009 RAC FMD exida Electrical & Mechanical Component Reliability Handbook MIL HDBK 217F 11

12 Sources of industry databases failure modes / distributions RAC FMD IEC (1 st edition) EN ISO (failure modes only) IEC (failure modes only) EN 298 (failure modes only) IEC Ed.1 /TR (formerly known as UTE C ) exida Electrical & Mechanical Component Reliability Handbook 12

13 Sources of failure modes / distributions IEC (1 st edition) 13

14 Sources of failure modes / distributions RAC FMD-91 14

15 Sources of failure modes / distributions ISO

16 Calculation examples SN

17 Calculation examples SN

18 Calculation examples IEC

19 Calculation examples IEC

20 Calculation examples IEC

21 Calculation examples FIDES Guide

22 Calculation examples FIDES Guide

23 Calculation examples FIDES Guide

24 Calculation examples FIDES Guide

25 Calculation examples FIDES Guide

26 Calculation examples FIDES Guide

27 Calculation examples FIDES Guide

28 Calculation examples FIDES Guide

29 Questions and Answers 29

30 Many Thanks for your Attention +49/ /10/