Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Basics of Failure Analysis

13,896 views

Published on

INTERNATIONAL COUNCIL ON SYSTEMS ENGINEERING

Published in: Engineering, Technology, Business

Basics of Failure Analysis

  1. 1. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 1 INTERNATIONAL COUNCIL ON SYSTEMS ENGINEERING Huntsville Regional Chapter Terry A. Kuykendall, Instructor Radisson Hotel 8720 Madison Blvd. Madison, AL
  2. 2. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 2 Basics of Failure Analysis Disclaimer: This paper was prepared and presented by Dr. Terry A. Kuykendall as a tutorial and training course sponsored by the Huntsville Chapter of the International Council on Systems Engineering (INCOSE), April 26th, 2002, for personnel seeking an introductory course in failure analysis. This paper, contents inclusive, are the intellectual property of Dr. Terry A. Kuykendall and Evolve Engineering & Analysis, LLC. For permission to reproduce any/all of the contents of this presentation, please contact the author at: Terry A. Kuykendall Evolve Engineering & Analysis, LLC 6020 Yorkridge Drive Alpharetta, GA 30005 P: 770-888-0898 C: 678-371-0285 terry@evolve-eng-llc.com www.evolve-eng-llc.com
  3. 3. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 3 Basics of Failure Analysis Course Objectives: 1. Develop an understanding of failure functions, concepts, and techniques 2. Review some of the techniques and methods of failure analysis 3. Participate in a workshop on practical application of failure analysis
  4. 4. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 4 Basics of Failure Analysis Role of Failure Analysis in Design and Engineering
  5. 5. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 5 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Kuykendall’s Fundamental Failure Theorem #1: “Failure is the basis for all scientific and engineering achievement.”
  6. 6. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 6 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Corollary to Failure Theorem #1: “Failure is Necessary to: 1. Establish a base of information upon which successes may be expected or predicted; 2. Define the boundaries and extent of the usefulness of an invention or discovery; and 3. Test the application of the Scientific Method.”
  7. 7. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 7 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Kuykendall’s Fundamental Failure Theorem #2: “Failures have been an important, dramatic, and sometime tragic (but necessary) part of our history, lives and evolution as a species.”
  8. 8. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 8 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Prehistoric Failure Analysis
  9. 9. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 9 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Excerpt from the Code of Hammurabi*: If a builder build a house for a man and do not make its construction firm, and the house which he has built collapse and cause the death of the owner of the house, that builder shall be put to death. If it cause the death of the son of the owner of the house, they shall put to death a son of that builder. If it cause the death of a slave of the owner of the house, he shall give to the owner of the house a slave of equal value. If it destroy property, he shall restore whatever it destroyed, and because he did not make the house which he built firm and it collapsed, he shall rebuild the house which collapsed from his own property. If a builder build a house for a man and do not make its construction meet the requirements and a wall fall in, that builder shall strengthen the wall at his own expense. * Sixth ruler, First Dynasty of Babylon, approx. 4000 years ago
  10. 10. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 10 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering The Pyramid of Dashur (the Bent Pyramid)
  11. 11. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 11 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Tacoma Narrows Bridge
  12. 12. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 12 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Three-Mile Island
  13. 13. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 13 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Challenger Accident
  14. 14. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 14 Basics of Failure Analysis – Role of Failure Analysis in Design and Engineering Kuykendall’s Fundamental Failure Theorem #3: “It is the responsibility of the practicing engineer or scientist to understand failures and their role in discovery, invention and design in order to minimize adverse affects to people and our environment.”
  15. 15. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 15 Basics of Failure Analysis Failure Analysis Concepts and Techniques
  16. 16. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 16 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Failure Analysis techniques are utilized to: 1. Obtain a better understanding of failure events and causative factors; 2. Develop remedial actions for the prevention of failure recurrence; and 3. Establish ownership of the failure (failed system) and responsibility for remedial action.
  17. 17. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 17 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Life Cycle Failures  Design-Related Failures typically occur when normal operational stresses exceed the design-basis strength;  Production- or Process-Related Failures typically occur when the design strength is degraded or overstressed by factors in the production process;  Use-Related Failures typically occur when the normal operating life is exceeded or abnormal operational stresses or maintenance-related stresses exceed the design strength in the use environment.
  18. 18. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 18 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Types of Failure Analysis Activities • Destructive Physical Analysis • Physics of Failure Analysis • Fault Tree Analysis • Common-Mode Failure Analysis • Failure Modes and Effects Analysis • Failure Modes, Effects, and Criticality Analysis • Functional Failure Analysis • Sneak Circuit Analysis • Software Failure Analysis
  19. 19. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 19 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Destructive Physical Analysis (DPA) • Involves methodical dissection, inspection and testing of unfailed parts or equipment • Most often performed for initial performance testing, or as a receiving inspection on samples of incoming items or materials (and may serve a QA/QC function) • May be utilized as an element of in-process verification • Uses a wide range of tools and techniques to determine physical abnormalities or process changes • Identifies unreported changes in design, materials, or production processes
  20. 20. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 20 Basics of Failure Analysis – Failure Analysis Concepts and Techniques ‘Physics of Failure’ Analysis • Sometimes called reliability physics, involves physical, chemical, and/or electrical analysis of failed assemblies, parts, equipment, or materials and investigation of the failure mechanisms • Typically applied in situations where there is some uncertainty with regard to the cause of failure (e.g., during acceptance testing, development growth testing, reliability demonstration tests, etc.) • May use equipment and processes similar to DPA, and seeks to identify the cause-and-effect relationship involved in the failure mechanism and process
  21. 21. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 21 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Fault Tree Analysis (FTA) • Developed by the aerospace industry to apply logic diagrams and Boolean algebra to represent and summarize the different events that can lead to an undesired event • Deductive, top-down method of analyzing system design and performance • Involves specifying a top event to analyze, followed by identifying all of the associated elements in the system that could cause the top event to occur • Utilizes symbolic representation of the combination of events resulting in the occurrence of the top event; events and “gates” are represented by symbols
  22. 22. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 22 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Example -- Simple Fault Tree
  23. 23. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 23 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Common-Mode Failure Analysis • Developed to analyze redundancy as a design tool to achieve reliability for the design of fault-tolerant systems • Evaluates failures that can bridge and defeat the redundancy factor by causing system failure by simultaneously sequentially impacting redundant elements • Considers failures that may be result from common causes such as fires, electrical overloads, maintenance or operations errors, etc. • The initiating event may be independent of, or external to, the specific system/equipment addressed by the analysis
  24. 24. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 24 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Failure Modes & Effects Analysis (FMEA) • Powerful tool that may be applied at any level of a system or process, and at any stage of development or operation • Evaluates the potential modes or methods of failures (single failure analysis), and estimates the postulated effects of these failures on the item, system, equipment, and/or operation • Aids in identifying design weaknesses and systems or equipment that can be rendered inoperable by common failure events • Provides a systematic method for documenting the results of the analysis for future consideration
  25. 25. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 25 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Example – FMEA Worksheet (1)
  26. 26. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 26 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Failure Modes, Effects & Criticality Analysis (FMECA) • Uses the same approach and methodology as the FMEA process • Adds an additional evaluation process to rank the relative importance (or criticality) of the failures under evaluation • Supports the allocation of limited resources to the system requiring the most consideration, or that requires design optimization
  27. 27. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 27 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Example -- Criticality Analysis Worksheet
  28. 28. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 28 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Functional Failure Analysis (FFA) • Utilized to identify and document the system elements, functions, and failure modes that are most important to maintenance and logistics planning • Uses many of the same input sources as the FMEA process; in addition, considers other input such as logistical support activities, maintenance concepts, level of repair assessments, and mission essential classification • Involves a worksheet format to evaluate each functionally significant item
  29. 29. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 29 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Sneak Circuit Analysis • Addresses failures in electrical or electronic systems when a latent path or condition causes an undesired event to occur, and/or inhibits the proper performance of a required function with the occurrence of a component failure • Evaluates sneak circuit problems such as: – Sneak Paths -- A design error that permits the flow of current over an unintended path – Sneak Timing -- The occurrence of a circuit function at an improper time – Sneak Label or Indication -- Incorrect or misleading labeling of a switch, display, or other interactive component
  30. 30. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 30 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Patterns Used in Sneak Circuit Analysis
  31. 31. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 31 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Software Failure Analysis • Evaluates problems and discrepancies occurring the in the design or operation of software (software error analysis) • Addresses software problems including: – Errors -- not failures, but are incorrectly computed values or conditions, or human errors that caused the fault in software – Faults – resulting directly from software errors or accidental conditions that may cause system or functional units to fail – Failures – may be produced by faults, may represent the loss of functional capability by a system element, or may involve the operational departure of a program from requirements • May involve a combination of analytical techniques
  32. 32. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 32 Basics of Failure Analysis – Failure Analysis Concepts and Techniques Software Failure Analysis Techniques  Stress Testing  Path Testing  Equivalence Classes  Symbolic Execution  Storage Testing  Boundary Value Analysis  Diagnostics  Logic Testing  Cause-Effect Graphing  Postfunctional Analysis  Simulation  Algorithm Evaluation  Top-Down or Bottom-Up Testing  Timing Analysis  Function Testing  Volume Testing  Execution Analysis  Static Analysis  Security Testing  Modeling
  33. 33. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 33 Basics of Failure Analysis – Failure Analysis Concepts and Techniques The Future of Failure Analysis Modern failure analysis may involve the deployment of multidisciplinary teams or task groups to study complex systems and functions that interact with operating and maintenance personnel, procedures and protocol, government regulations, legislation, political action, the environment, and the general public. Examples of modern systems and operations that have required failure analyses include nuclear power, missile ranges, food and chemical processing, offshore oil drilling, rail transportation, and automobiles.
  34. 34. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 34 Basics of Failure Analysis Relationship of Failure Analysis to Other Studies and Evaluations
  35. 35. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 35 Basics of Failure Analysis – Relationship of Failure Analysis to Other Studies and Evaluations Failure analyses receive input from, provide output to, and interact with a number of engineering studies such as: • Safety/Hazards Analyses • Reliability, Availability, and Maintainability (RAM) Analyses • Human Factors Analyses • Design Criteria and Specifications • Engineering Studies and Analyses • Operations Procedures and Protocol
  36. 36. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 36 Basics of Failure Analysis – Relationship of Failure Analysis to Other Studies and Evaluations Typical Failure Analysis Interactions Reliability, Availability, and Maintainability Analysis Failure Analysis Human Factors Analysis Preliminary Design Information and Documentation Preliminary Hazards/Safety Analyses Design/Operations:  Facility Design Documentation  System Design Documentation  Process Hazards Analyses  Hazards and Operability Studies  Safety Analyses and Reports  Time and Motion Studies  Dynamic Process Analyses  Mathematical/Parametric Studies  Data Base Development  Computer Modeling  Statistical Analysis
  37. 37. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 37 Basics of Failure Analysis – Relationship of Failure Analysis to Other Studies and Evaluations Input to Failure Analyses • Preliminary design information provides the description of the systems/equipment to be analyzed, and some insight on potential failure modes • Preliminary design information also provides the basis for comparison of failure mechanisms to industry standards, failure data bases, and vendor specifications that identify expected failure and reliability data • Preliminary safety and hazards analysis information establishes where hazardous materials and energies exist, and where failure may manifest in the most severe conditions and results
  38. 38. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 38 Basics of Failure Analysis – Relationship of Failure Analysis to Other Studies and Evaluations Relationship to RAM Analyses • Failure and reliability are (in general) inverse functions, so there is a natural relationship between the rate of failure and the projected reliability of systems, equipment, and processes • Reliability, Availability, and Maintainability (RAM) analyses typically are conducted utilizing information provided by failure analyses • Failure information may provide input and the basis for reliability analyses; however, in situations where reliability information is known or is considered to be design basis criteria (e.g., an established process throughput), reliability data can serve as input for failure analyses
  39. 39. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 39 Basics of Failure Analysis – Relationship of Failure Analysis to Other Studies and Evaluations Relationship to Human Factors Analyses • Human action, process intervention and control, and human error are often contributors to failure modes and events that exacerbate failure scenarios • Human Factors Analyses provide summaries of conditions, situations, and functions where human actions may induce failure, thereby identifying areas where additional considerations are required for failure detection, prevention, and mitigation • Human Factors Analyses may be developed concurrently with failure analyses, or may precede or follow failure analyses; ideally, the information associated with human failure will be included in both analyses and will address failure concerns from the different perspectives of the specific analytical processes
  40. 40. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 40 Basics of Failure Analysis – Relationship of Failure Analysis to Other Studies and Evaluations Output of Failure Analyses • The information on process, equipment, and operational failure compiled by failure analyses provides specific criteria that can be integrated into design and operations to ensure that adequate functionality has been incorporated • Failure analyses identify situations where failure is the initiating or contributing cause of scenarios and event sequences that can include accident conditions, thereby providing input for safety and hazards analyses • Failure analyses also aid in defining the limitations, boundaries, and constraints on designed systems and operations that are required for the development of process models, simulations, and detailed engineering analyses
  41. 41. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 41 Basics of Failure Analysis Failure Classification and Categorization
  42. 42. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 42 Basics of Failure Analysis – Failure Classification and Categorization Classification and Categorization  Failures may be classified based on the severity of the results of the final manifestation of the failure  Classification can be based on the unmitigated results of the failure (typical FMEA approach), and/or by taking credit for planned prevention and mitigation measures  Failures can be categorized based on importance to the program, operations, and other functional concerns (e.g., safety, environmental protection, quality assurance)
  43. 43. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 43 Basics of Failure Analysis – Failure Classification and Categorization Failure Classification  Based on grouping by severity (consequence) of failures  Number of levels of severity may be assigned based on the complexity and types of consequences relevant to the specific operations  Levels of severity typically are associated with the types and levels of hazards associated with the facility or processes
  44. 44. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 44 Basics of Failure Analysis – Failure Classification and Categorization Typical 4-Part Classification Scheme* Category I – Catastrophic: A failure that may cause death or high/major system loss Category II -- Critical: A failure that may cause severe injury, major property damage or major system damage that will result in mission loss Category III – Marginal: A failure that may cause minor injury, minor property damage, or minor system damage that will result in delay or loss of availability or mission degradation Category IV – Minor: A failure not serious enough to cause injury, property damage, or system damage, but that will result in unscheduled maintenance or repair * Similar to that proposed in MIL-STD-1629A, “Procedures for Performing a Failure Mode, Effects and Criticality Analysis”
  45. 45. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 45 Basics of Failure Analysis – Failure Classification and Categorization Example Categorization Approach High Priority/Consideration -- Failures that have the potential for severe safety or environmental consequences, or that can impact mission success Intermediate Priority/Consideration -- Failures that have the potential for moderate safety or environmental consequences, or that can impact process throughput Low Priority/Consideration -- Failures that have only minor potential for safety impact, little or no environmental consequences, and that have only temporary impact on operations
  46. 46. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 46 Basics of Failure Analysis The Failure Modes and Effects Analysis (FMEA) Process
  47. 47. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 47 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Objectives 1. Present the basis, rationale and decision criteria for the application and implementation of FMEAs 2. Discuss the philosophy and approach for the setup and conduct of FMEAs 3. Explore tools and techniques useful for the implementation of the FMEA process
  48. 48. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 48 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process The FMEA Process • Evaluates failure modes of a given system, subsystem, component or process for the effects on other components and ultimate effects on the overall parent system or facility. • Examines structures, systems, and/or components (SSCs) to analyze and evaluate normal operating modes, off-normal and transient modes, failure modes, and consequences. • Identifies failures, weaknesses and hazards that have the potential to exceed design basis and/or accident criteria. • Identifies problem areas and supports development of corrective actions for any condition that could jeopardize the project integrity, imperil human safety or result in unacceptable system damage.
  49. 49. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 49 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process FMEA Philosophy • “Bottoms-up” approach to analyzing system design and performance • Lowest levels of systems/components are outlined and defined • Potential failures of lower level items are defined, and effects of failures are determined • Failures are summed to provide an analysis of systemic failure • Involves evaluation of the likelihood and severity of failure, and effects on related/embedded systems
  50. 50. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 50 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process It is important to remember: • There are many ways that FMEAs can be formatted; there is no “one way” or “right way” • As long as the process completes the objective of evaluating failure at the appropriate or desired level, the process and format are valid • FMEAs may be tailored to the needs of the analyst on a case- by-case and project-by-project basis • FMEAs may be conducted in sequences of increasing complexity or to provide additional detail in subsequent design development
  51. 51. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 51 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process FMEA Team Composition • FMEA team lead (systems engineer) • Technical/design representatives (discipline engineers) • Operations and maintenance personnel • Safety, environmental, and quality assurance specialists • Topical/technical specialists • Equipment suppliers/vendors (as appropriate)
  52. 52. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 52 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process FMEA Worksheets • Allow organization and cataloging of FMEA information • Ensures a uniform formatting and approach for efforts • Provide a means of grouping information and data • Promote integration into a data base management and results tracking system • Serves as a guide to the analyst to ensure that important information is captured and logged
  53. 53. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 53 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Example -- FMEA Worksheet (2)
  54. 54. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 54 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Two Functional Categories of FMEAs 1. Components-Level FMEAs 2. Systems-Level FMEAs
  55. 55. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 55 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Components-Level FMEAs • Evaluates failure modes and effects at the components level (i.e., smallest functioning unit) of design, engineering or operation • Addresses components [typically]as complete functioning units (rather than as parts) • Facilitates analysis of complex components by subdividing the component into operational subcomponents • Provides evaluation of probability (likelihood) and frequency (rate) of failure
  56. 56. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 56 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process When to Use Components-Level FMEAs • When information is required on the anticipated failure of parts or components in order to assess the effect on the parent system or operation • When design has been developed to the stage where details on the most likely components are available • When detailed design assessments are required for design completion and failure is a criterion • When components alternatives are under consideration, and comparative information is required
  57. 57. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 57 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Output of Components-Level FMEAs • Identifies hazards and safety issues of specific parts of equipment or systems • Focuses the designation and specification of safety and non- safety related parts, components, and systems • Develops information that can be utilized for specifications, procurement, and operations/maintenance • Defines the basis for component tolerance, operating conditions, and limitations
  58. 58. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 58 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Summary -- Components-Level FMEAs: • Are used when specific information is required at the lowest (most detailed) level of design • Provide criteria that is used to support specification of parts and components • Determine the lowest level of system function that must be classified as safety significant
  59. 59. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 59 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Systems-Level FMEAs • Addresses failure modes and effects at the systems level (e.g., higher level of design detail than components) • Divides the facility, structure, or operation into functional groupings or systems • Defines the functional boundaries and interfaces between systems • Treats each system as a compilation of subsystems that comprise a “black box” • Provides no evaluation of probability or frequency of failure (e.g., all failures occur, effects are instantaneous)
  60. 60. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 60 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process When to Use Systems-Level FMEAs • When information is needed for decision-making processes (e.g., trade studies), but design is not sufficiently progressed for components analysis • When making preliminary determinations of which systems are critical, and therefore deserve early emphasis and design focus • When making preliminary assessments of which systems are important to safety
  61. 61. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 61 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Output of Systems-Level FMEAs • Identifies the hazards most likely to be of concern to the processes and operations • Allows the preliminary identification of safety and non-safety related systems • Provides a mechanism to reduce the number of systems, hazards, and scenarios that must be submitted for more rigorous safety evaluation • Develops information to be utilized in other systems engineering and/or safety analyses (e.g., HAZOPS, PHA, ETA/FTA, etc.) • Provides input for RAM analysis information to support design decisions
  62. 62. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 62 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Summary -- Systems-Level FMEAs: • Are useful for application when limited input is available, but output information is necessary for design to progress • Provide an important base of information that supports subsequent engineering analyses and evaluations • Allow limited resources to be applied to the most important and critical systems design
  63. 63. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 63 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process FMEA Software Commercially-available software packages (e.g., FMEA data base software) may be utilized to: 1. Expedite the conduct of multiple/concurrent FMEA efforts; 2. Maintain consistency among a large number of FMEA modules, and among multiple analysts; 3. Guide the FMEA effort by providing a reference-based format; 4. Ensure compatibility of the FMEA with future, more detailed efforts (e.g., Components-Level FMEAs) 5. Provide a ready (translational) basis for performing RAM analyses.
  64. 64. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 64 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process Examples of FMEA Software  FMEA/FMECA, Relex Software Corporation  FMECA, FRACAS, Advanced Logistics Developments, Inc.  FMEA Software Tool, International SEMATECH, Inc.  Process & Design FMEA, SoHar Corporation  FMEA-Pro5 Dyadem International Limited  FMEA Investigator (Training Software), Resource Engineering, Inc.
  65. 65. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 65 Basics of Failure Analysis – The Failure Modes and Effects Analysis (FMEA) Process References and Information Sources • Guidelines for Hazard Evaluation Procedures, Center for Chemical Process Safety, American Institute of Chemical Engineers • MIL-STD-1629A, Procedures for Performing a Failure Mode, Effects and Criticality Analysis • Handbook of Reliability Engineering and Management, Ireson, W.G. and C.F. Coombs, Jr. • RADC-TR-83-72, The Evolution and Practical Applications of Failure Modes and Effects Analyses, Rome Air Development Center, Air Force Systems Command • ARP-926, Design Analysis Procedure for Failure Mode, Effects, and Criticality Analysis (FMECA), Society of Automotive Engineers • NASA Bibliography data base: http://www.sti.nasa.gov/new/fmec33.html
  66. 66. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 66 Basics of Failure Analysis FMEA Workshop
  67. 67. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 67 Basics of Failure Analysis – FMEA Workshop Workshop Objectives 1. Understand the fields and required inputs for an example FMEA worksheet 2. Implement the FMEA process by utilizing a systems-level FMEA worksheet 3. Divide into working groups (FMEA teams) and prepare systems-level FMEAs on common topics 4. Present the results of the FMEA process
  68. 68. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 68 Basics of Failure Analysis – FMEA Workshop Example -- Systems-Level FMEA Worksheet (3) Failure Identification Failure Effects Severity Class* Operations and Protective Features Comments RecordNo. Subsystem orItem Function Failure Mode Causes LocalEffect NextHigher Effect EndEffect Chemicalor Explosive Industrial Safety System Damage Operational Phase Detection Prevention Mitigation Interfaces; Comments * Range from Minor Impact (1) to Extremely Severe (5 or 6)
  69. 69. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 69 Basics of Failure Analysis – FMEA Workshop Input for Worksheet Columns (Part 1) Record #: Tracking numbers for the FMEA data base system. Subsystem: Utilized to specify the subsystem or subprocess within the scope of each individual systems-level FMEA. A subsystem is a functional unit within the parent system that has been separated out as a distinct operation that can be analyzed as a separate entity. Item: Utilized when the previous Subsystem column addresses a functional unit that is so complex that it requires additional subdivision, or a unit that is difficult to define as a discrete function so that related systems or processes are included for convenience of analysis. Function: The function of each subsystem or process is described briefly in a manner that provides a distinct statement of the system or process being evaluated. The description of function considers that the loss or degradation of the identified function or functions as a result of the relevant failure mode will be the subject of the subsequent analysis.
  70. 70. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 70 Basics of Failure Analysis – FMEA Workshop Input for Worksheet Columns (Part 2) Failure Mode: The failure mode specifies the consequence of the mechanism through which a failure occurs. A failure mechanism may include physical, chemical, electrical, thermal, or other processes that result in failure. In general, a failure mode describes an event or inoperable state in which any system or subsystem does not, will not, or cannot perform as originally or previously specified (normal operating state). For the most part, the systems-level FMEAs consider only single-point failures where the failure of an item would result in the failure of the system and does not have redundancy or alternative operational procedures. Items such as redundancy and procedures may be addressed in the columns for Prevention and Mitigation. Each failure is considered to be an independent occurrence, with no relation to other failures in the system except for the subsequent effects produced by the failure under evaluation.
  71. 71. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 71 Basics of Failure Analysis – FMEA Workshop Input for Worksheet Columns (Part 3) Causes: Presents the root causes directly related to the relevant failure mode. The causes specify the physical or chemical processes, design defects, quality defects, operational misapplication, or other processes that are the basic reason for the failure or that indicate the physical process by which deterioration leads to failure. Phase: Refers to the operational mode of the subsystem or process under evaluation (e.g., normal operations, maintenance, standby operations, shutdown conditions, etc.). If the subsystem or item is subject to different modes of operation, each operational mode is identified and analyzed separately. Detection Method: This column documents the means by which the failure mode is detected. These detection methods may include equipment such as visual or warning devices, automatic sensing devices, sensing instrumentation, or other unique indicators. If no means of detecting a failure event are provided, this should be indicated.
  72. 72. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 72 Basics of Failure Analysis – FMEA Workshop Input for Worksheet Columns (Part 4) Local Effect: The consequence of a failure on the operation, functions, or status of the specific item being analyzed for the failure. For some simple failures, the local effect may be the only effect of the failure. Next Higher Effect: Builds upon the information provided in the Local Effect column, and provides further development of the failure scenario. Some failures may have only a local affect and the next effect, which would represent a combination next higher effect and end effect. End Effect: The final effect of the failure within the confines of the boundaries established for the FMEA system under scrutiny. The end effect should postulate the ultimate results of the potential failure in terms of effects on subsystems, processes, and environs of the system being analyzed.
  73. 73. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 73 Basics of Failure Analysis – FMEA Workshop Input for Worksheet Columns (Part 5) Severity Level: Provides a subjective ranking of severity of worst consequence of the failure mode being analyzed. Severity evaluation includes assessment of the degree of injury, release of energy and/or hazardous materials, and systems damage. Each category has interrelated levels of impact (in order of increasing severity), such as: Minor Impact, Limited Impact, Moderate Impact, Significant Impact, Serious Impact, and Extremely Serious Impact. Detection: Devices and processes utilized to detect an aberrant condition, undesirable trend, or a failed condition. Prevention: Presents any features, devices, or other mechanisms that can prevent the failure from happening. Mitigation: Those features, devices, procedures, or other mechanisms that can lessen the likelihood of an occurrence or lessen the severity of the impact of an occurrence, but that cannot actually prevent the occurrence.
  74. 74. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 74 Basics of Failure Analysis – FMEA Workshop Input for Worksheet Columns (Part 6) Interfaces/Comments: Utilized to establish and document the interfaces of the subsystem under scrutiny to other systems and subsystems. Items that are included are the systems, external to the system being analyzed, that provide a common boundary or service and are necessary for the system to perform its mission in an undegraded mode (e.g., power, cooling, control systems, etc.). This is especially important where the results of a failure within the system under analysis have effects on other systems in a chain-of-events sequence. This column also is important for establishing operating interfaces that may be of concern for process/materials flow and plant functionality.
  75. 75. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 75 Basics of Failure Analysis – FMEA Workshop Exercise - FMEA Worksheet System Analyzed: Subsystem orItem Function Failure Mode Causes LocalEffect NextHigher Effect EndEffect Severityof Impact* Detection Prevention orMitigation * Apply a scale of Minor Impact (1), Moderate Impact (2) and High Impact (3)
  76. 76. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 76 Basics of Failure Analysis – FMEA Workshop Exercise -- FMEA Worksheet Instruction (Part 1) Systems Analyzed: Input the title of the topic your team is evaluating. Subsystem or Item: If the topic (system) that you are analyzing is more easily evaluated by breaking it down into smaller pieces, list these pieces (no more than three for this exercise) in the rows of this column. If not, the first row will be the same as the System Analyzed. Function: Describe (in very general terms) the function of each subsystem or item that is being analyzed in a manner that promotes the explanation of the failure mode in the subsequent analysis. Failure Mode: State the failure mode of the subsystem, describing the type of failure that may occur and/or the inoperable state in which any system or subsystem does not, will not, or cannot perform as it is supposed to function.
  77. 77. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 77 Basics of Failure Analysis – FMEA Workshop Exercise -- FMEA Worksheet Instructions (Part 2) Causes: Provide a brief statement of the root cause of the failure in terms of the initiating event and other contributing processes that are the basic reason for the failure. Local Effect: State the consequence of the failure on the operation, functions, or status of the specific item being analyzed for the failure. Next Higher Effect: State the effect of the failure on the next larger function or system in which the Local Effect is imbedded. . End Effect: State the final effect of the failure within the confines of the boundaries established for the FMEA system under scrutiny, such as the total system or process affected by the final expression of the selected failure.
  78. 78. HHuunnttssvviillllee RReeggiioonnaall CChhaapptteerr April 26, 2002 78 Basics of Failure Analysis – FMEA Workshop Exercise -- FMEA Worksheet Instructions (Part 3) Severity of Impact: Provide a subjective ranking of severity of worst consequence of the failure being analyzed (e.g., injury, damage, etc) using a scale of (1) Minor Impact, (2) Moderate Impact, and (3) High Impact. Detection: List any devices or processes that could be used to (1) detect the upcoming failure before it occurs, (2) recognize a failing condition or undesirable trend, (3) report the failed condition after failure. Prevention or Mitigation: List any features, devices, or other mechanisms that could be used to prevent the failure from happening, or those features, devices, procedures, or other mechanisms that can lessen the impact of the failure after occurrence.

×