Influence of Environmental Loading Factors on System Design



Published Jul 5, 2016
Paddy Conroy Jacek Stecki Andrew Thorn


A closed-loop, iterative FMEA/FMECA process is vital for a safe design, but the challenge is in performing these analyses in such a way that alternate scenarios can be rapidly considered, and changes implemented to improve the design. This paper identifies an explicit model-based method to optimise system design by linking the failure identification process to specific operating scenarios and environmental conditions (Environment Loading Factors (ELF)). Current methods exist to define operating scenarios for FMEA/FMECA, but are limited by the lack of connectivity and traceability between the two. Without connectivity a failure mode analysis is limited in scope, and emergent scenarios cannot be easily understood without repeating the entire analysis process. This paper outlines a model-based method to define operating scenarios, each with a user defined Operating Environment (OE). The OE is defined by a set of Environmental Factors (based on a taxonomy) and is then used to modify the expected criticality of associated physical failures of the system. By linking physical failures to an operating scenario, changes to the operating scenarios can be made to automatically update and advise failure mode changes to the design FMEA/FMECA. The linkage can be used to explore a wider variety of operating conditions and use-cases, including the ability to perform trade studies to compare different environments and examine their impact on the design. By comparing and assessing operating environments concurrently in the design process, a safer and more robust design can be realised.

How to Cite

Conroy, P., Stecki, J., & Thorn, A. (2016). Influence of Environmental Loading Factors on System Design. PHM Society European Conference, 3(1).
Abstract 148 | PDF Downloads 171



failure modes effects and criticality analysis (FMECA), environmental stresses (ESs), model-based FMEA, Design, mission planning

Ford Motor Company (FMC) (2004), FMEA Handbook Version 4.1
Ministry of Defence (MOD) (2012), Defence Standard 00-45: Using Reliability Centred Maintenance to Manage Engineering Failures
SAE International (1996), ARP2761: Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems Equipment
Saaty, T.L. (1980), The analytical hierarchy process: Planning, priority setting, resource allocation. NY, USA: McGraw-Hill
Saaty, T.L. (1990). How to make a decision: The analytical hierarchy process. European journal of operational research, vol. 48, pp. 9-26, North-Holland
System Reliability Center (SRC) (2001), Environmental Effects on Mechanical Design
US Department Of Defense (USDOD) (1991), MIL-HDBK-217F: Reliability Prediction of Electronic Equipment
US Department Of Defense (USDOD) (1998), MIL-HDBK-338B: Electronic Reliability Design Handbook
US Department Of Defense (USDOD) (1980), MIL-STD-1629A: Procedures for Performing a Failure Mode Effects and Criticality Analysis
US Department Of Defense (USDOD) (2000), MIL-STD-810F: Environmental Engineering Considerations and Laboratory Tests
US Naval Surface Warfare Center (USNSWC) (2010), NSWC-10: Handbook of Reliability Prediction Procedures for Mechanical Equipment
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