1、SAE AIR*4845 93 7943725 0537425 50L 400 Commonwealth Dnve. Warrendale. PA 15096-0001 Submitted for recognition as an American National Standard I THE FMECA PROCESS IN THE CONCURRENT ENGINEERING (CE) ENVIRONMENT FOREWORD This SAE Aerospace Information Report (AIR) by the G-11AT (Automation and Tools)
2、 subcommittee of the SAE 6-13 RMS Committee, examines in detail the failure mode, effects and criticality analysis (FMECA) and how it relates to concurrent engineering. of the RMS disciplines. The report outlines the FMECA process and the users of the FMECA as it is currently performed and indicates
3、 the various requirements which the analysis satisfies. process could be automated and how this may be accomplished. Finally a set of recommendations are given for integrating FMECA automation into the concurrent engineering process. FMECA is probably the most labor intensive analysis performed by a
4、ny Suggestions are made on which parts of the current SAE Technical Standards Board Rules provide that: This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary. and its applicability and suitability for any particular u
5、se, including any patent infringement arising therefrom, is the sole responsibility of the user.“ SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 1993 Society of Automo
6、tive Engineers, Inc. All rights reserved. Printed in USA SAE AIR+4845 93 7943725 0537426 Y48 -e a a SAE AIR4845 TABLE OF CONTENTS 1 . SCOPE . 3 2 . REFERENCES 3 2.1 SAE Publications . 3 2.2 Military Publications . 3 2 -3 Other Publications 4 2.4 ListofAcronyms . 4 3 . TECHNICAL REQUIREMENTS 5 3.1 3.
7、2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.2.7 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 3.4 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 3.4.6 3.5 FMECA Overview 5 The Current FMECA Process . 6 FMECANeeds 6 FMECA Requirements 10 FMECA in the Current Design Process 12 Initiating the FMECA . 23 Generation of the FMECA Report
8、26 Current Difficulties (With Generating FMECAs) . 26 Relevant Aspects of the CE Environment 29 The Role of the FMECA in the CE Environment 31 Timing 31 Users of the FMECA Data in a CE Environment 32 Benefits of FMECA in the CE Environment 32 Automation of FMECA Within CE . 33 Information Gathering
9、. 33 Analyses . 34 Report Generation . 34 Todays Capabilities . 35 Needed Automation Capabilities 37 Technology Needs (to Automate FMECA) . 48 Priority for FMECA Automation . 49 FMECA Control/FMECA Control to a Hardware Configuration 24 FMECA in the Concurrent Engineering Environment 27 4 . SUMMARY
10、AND RECOMMENDATIONS 49 APPENDIX A EXAMPLES OF DIFFERENT TYPES OF FMECA . 51 -2- SAE AIR*4845 93 7943725 0537427 384 1. 2. SCOPE: This AIR by the G-IlAT (Automation and Tools) subcommittee, examines the failure mode, effects and criticality analysis (FMECA) requirements and procedures as performed on
11、 current and earlier vintage engineering programs. The subcommittee has focused on these procedures in relation to the concurrent engineering (CE) environment to determine where it may be beneficial, to both FMECA analysts and users, to automate some or all of the FMECA processes. Its purpose is to
12、inform the reader about FMECAs and how the FMECA process could be automated in a concurrent engineering environment. intent on the part of the authors that the material presented should become requirements or specifications imposed as part of any future contract. There is no The report is structured
13、 to include the following subjects: a. A FMECA overview b. The current FMECA process c. d. FMECA automation e. The benefits of automation FMECA in the concurrent engineering environment REFERENCES: The following publications form a part of this specification to the extent specified herein. The lates
14、t issue of all SAE Technical Reports shall apply 2.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. 2.1.1 Reliability, Maintainability czior ug7rls -Bleed hydraulic fluid FIGURE 5 - System Functional Block Diagram (ARP926A, Figure 3) SAE AIRa4845 93 m 794372
15、5 0537444 463 m 2 1 4 1 t - 20 - SAE AIR*4845 93 D 7943725 0517445 3TT = SAE AIR4845 1 -4 t - 21 - SAE AIRx4845 93 = 7943725 05i1744b 23b SAE AIR4845 3.2.3.1.3 (Continued) : A thorough FMECA analysis requires the utilization of the three different forms of design representation described. block diag
16、rams and schematics allow a good and rapid understanding of the design intent and they may identify areas of concerns and deficiencies. intent and they may reveal deficiencies that were not visible on diagrams and schematics. areas of concern revealed by schematics and diagrams have been properly ad
17、dressed. The functional The drawings represent the execution of the design Drawings can also be used to confirm that 3.2.3.2 Major Types of FMECA: Appendix A contains examples of the hardware and functional FMECAs described in this section. The FMECA examples are generic, for reference only and shou
18、ld not be construed as representing any specific product or component. 3.2.3.2.1 3.2.3.2.2 Functional FMECA: A functional FMECA is performed early in the design process (e.g., during the concept development and proposal phases) when only a high level description of the system design has been establi
19、shed. It is aimed at evaluating design options and influencing the direction the final design will take. The type of design documentation needed to perform a functional FMECA includes: functional block diagram; reliability block diagram; mission phase definition; missionlsystem time profile; environ
20、mental profile; high level definition of the systems health monitoring subsystem; and functional failure modes and failure mechanisms. It defines failure modes and system effects, failure modes that must be eliminated or mitigated, undetected failure modes, fault detection and isolation tests or dia
21、gnostics required. The functional FMECA provides input to the testability, safety, maintainability and LSA groups and should be completed prior to the system preliminary design review. Hardware FMECA: continues through higher levels of design (component, subsystem, system). It is done iteratively an
22、d incrementally as the design evolves and helps to improve the detailed hardware design. documentation needed for a hardware FMECA includes: schematics; parts lists; and detailed parts drawings. The outputs include a matrix of all failure modes producing the same failure indication; the failure effe
23、ct at all levels up to the system level; a detailed failure rate prediction or probability of occurrence; and the criticality of each failure mode. The hardware FMECA provides input to testability analyses and refines the functional FMECA as the detailed design matures. The detailed FMECA should be
24、completed before the critical design review. The hardware FMECA starts at the piece part level and The design - 22 - SAE AIR+4845 93 7943725 0537447 372 = SAE AIR4845 3.2.4 Initiating the FMECA: 3.2.4.1 FMECA Overview: As mentioned earlier, to influence design the FMECA logic must be developed and d
25、ocumented concurrent with the development of the design itself. only documented after the design is fixed. concept should have a FMECA completed before further detailed design proceeds. approved FMECA should be attached. This process requires constant updating of the FMECA and thereby provides an au
26、dit trail for the decisions that determined the final design all the way from the first concept. The FMECA is not an effective design tool if it is Each preliminary design Before a preliminary design idea is approved or progresses an 3.2.4.2 FMECA Phases (Type and Depth): The different types of FMEC
27、A were addressed in 3.2.3.2. function of the customers requirements, the contractors experience, the available funding for the task and the time schedule for completion of the task. The depth of analysis must keep pace with the product design. As more detail of the design is decided the FMECA must b
28、e constantly revised. The depth to which FMECAs are completed is a The FMECA process begins the same day a concept or idea is perceived. At this stage a functional FMECA is started, because in most cases the hardware is still undefined. One of the most common reasons for delaying the FMECA is the de
29、sire for “real“ data to support the design assumptions. If the designers wait until test or analysis data are available to substantiate the design there will be long program delays. The assumptions made in the FMECA will be confirmed or rejected as the design progresses and various analyses and test
30、s are completed. FMECA assumptions must be documented and updated or corrected as data become available. 3.2.4.3 Flow Down of FMECA Requirements: It is the responsibility of the prime contractor to flow down FMECA requirements to subcontractors and vendors to ensure completeness and compatibility wi
31、th program requirements. direction should provide examples of the depth of analysis required for each stage of development. The goal is to document all design concepts and to require a completed FMECA before the subcontractor or vendors design is approved. This 3.2.4.4 Data to Support a FMECA: Desig
32、n information needed to support the FMECA i ncl udes : a. Equipment and part drawings, design descriptions and design change history, system schematics, functional block diagrams, and narrative descriptions b. Relevant military, commercial, company and customer specifications, and design guide1 ines
33、 for the equipment being analyzed - 23 - SAE AIR+Lt81i5 93 7993725 05l17YY8 009 SAE AIR4845 3.2.4.4 3.2.4.5 (Continued): c. Reliability data, including historical data on failures, cause and effect analyses of previous failures, part failure rates, field service data, and the effects of environmenta
34、l factors such as temperature, radiation, moisture, vibration, dust, etc. on the part and equi pment re1 i abi 1 i ty d. Operating specifications and limits, interface specifications, and configuration management data Maintainability data including test equipment and scheduled maintenance intervals.
35、 e. Failure modes, failure rates/ratios and failure effects can be based on similar in-service systems or hardware. FMECA failure data must be developed from conservative assumptions. Early identification of these assumptions may indicate the need for testing to verify them before changes become too
36、 costly. A detailed description of the operating environment is needed to assess the probability of a failures occurrence. In addition, a detailed mission profile and the mission operating requirements are needed to assess the importance of certain failures at the system level. If the design is uniq
37、ue then the Previous substantiated FMECA analyses on similar parts and equipment are useful for organizing the analysis, for ensuring that a complete FMECA has been done and as a source for appropriate failure mode, effects and criticality evaluation. FMECA Level: If the FMECA keeps pace with the de
38、sign there is no need to specify the level of FMECA detail required at any particular design phase. is the relationship to other systems. To prevent loss of this relationship an upper level functional relationship FMECA should be performed from time to time during the design. between systems will be
39、come more clear as the design nears completion. This raising of the analysis will also show the failure modes that can be handled as a group if they have similar severity consequences. What can be lost in developing FMECAs concurrent with the design The failure relationship 3.2.5 FMECA Control/FMECA
40、 Control to a Hardware Configuration: Controls of the FMECA process help to ensure that it is an integral part of the design process; is dynamic, and that revisions must be formally documented and linked to design changes. 3.2.5.1 Definition: FMECA control is defined as the methods or procedures tha
41、t ensure : a. b. That design changes are captured by FMECA revision; and That the FMECA completely and accurately reflects the design; - 24 - SAE AIR*4845 93 m 7943725 0537449 T45 SAE AIR4845 3.2.5.1 3.2.5.2 3.2.5.3 (Continued): c. That FMECA results are distributed to appropriate in-house and exter
42、nal users. d. That FMECA meets the needs and requirements of the customer and solicits feedback. Controls for FMECA Preparation: stages assure that: Controls during the FMECA preparation a. The FMECA is performed to the appropriate indenture level and detail. b. c. The FMECA is linked to a specific
43、hardware configuration. The FMECA is linked to a specific product application or environment. Typically, this control is established as part of the initial FMECA task definition. specify: a. Whether the FMECA should be done to the system, subsystem, or piece b. The task definition should be formally
44、 documented and part level. The parts list or bill of material of the product configuration to be analyzed. c. The product application and environment, including such details as: (1) (2) (3) Preventive maintenance and inspection intervals Available failure detection means (such as aircraft cockpit d
45、i splays) Environment variables such as pressures, temperatures, loads, and operating times and frequencies Controls also provide a structured FMECA filing system so that in-process and completed FMECAs can be conveniently accessed by using groups. A centralized computer data base, if available, fac
46、ilitates convenient access. Completed FMECA reports should be formally published, serialized and filed in the company or department library. Controls During Revision Cycle: or evaluated, the FMECA should be used to assess their impact on re1 i abi 1 i ty and safety. As product design changes are pro
47、posed Controls provide the structure to ensure that: a. All design changes trigger a FMECA effort b. FMECAs become an integral part of evaluating the design change c. FMECA revisions are formally documented, and linked to the corresponding design change documents - 25 - SAE AIF?*4845 93 m 79Y3725 05
48、17450 b m SAE AIR4845 3.2.5.3 (Continued): FMECA revisions may also be needed to reflect testing or field service experience, or to incorporate review comments from interfacing disciplines. Controls provide a history of these FMECA revisions, and the background and rationale for each. 3.2.5.4 Contro
49、ls for FMECA Distribution: As the FMECA results are distributed to the using organizations, controls are needed to: a. Tailor the report format to the needs of each user b. Allow users to provide feedback c. Ensure appropriate reviews and approvals precede external distribution 3.2.5.5 Implementation of FMECA Controls: FMECA controls should be defined and enforced vi a formal company or department procedures. procedures should completely define the “who, how, and when“ of each step in the FMECA process. These pub1 i shed 3.2.6 Generation of the FMECA Report: In the past for many comp
