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Safety and Reliability Methodology

The guideline VDI 4002-2 Reliability Engineer – Requirements for Qualification provides a curriculum on the educating of reliability engineers covering the basic safety and reliability methodology. The guideline defines a qualification programme such as can be implemented at universities, universities of applied sciences, technical engineering colleges, and further education institutes. The VDI 4002-2 has been authored by the Working Group Education assigned to the Reliability Engineering Department of the VDI (German Engineer Association). The curriculum is structured in eight modules namely

Outlines of modules addressed to safety and reliability methodology are given below. The guideline has been published by Beuth-Verlag. Contents and introduction download is free.

 
Module 1
Fundamentals and
Reliability Methodology, Part 1
  1. Introduction
    • Terminology: Terms and definitions
    • Reliability engineering duringu development process
    • Customer viewpoint, customer requirements, and manufacturer responsibilities
    • Assessment of reliability targets
    • Causes of unreliability; reliability concepts, benefits
    • Context of reliability, maintainability, and safety
    • Difference between design failure and physical failure

  2. Mathematical Aspects of Reliability Modelling
    • Fundamentals of probability theory and statistics
    • Application of probability functions for reliability modelling
    • Exercises

  3. Fundamentals
    • System definition, system boundaries, system analysis
    • Qualitative versus quantitative approaches
    • Analytical versus statistical approaches
    • Inductive versus deductive approaches
    • Avoidance of design failures

  4. Data
    • Origin, structure, and quality of reliability data
    • Data sources
    • Evaluation of reliability data
    • Application examples
    • Exercises

  5. Data Analysis
    • Order statistics and their distributions
    • Graphic analysis
    • Evaluation of incomplete (censored) data
    • Confidence intervals
    • Exercises

  6. Reliability Test Planning
    • Test planning based on the binomial and Weibull distribution
    • Lifetime ratio, failures during a test
    • Accelerated lifetime tests, time-acceleration models
    • Correlation between test and operation
    • Application examples
    • Exercises

  7. Failure Mode and Effects Analysis (FMEA)
    • Introduction
    • Method
    • FMEA worksheet
    • FMEA report
    • Applications
    • Relationships with other methods
    • Description of the FMEA documentation
    • Application examples
    • Exercises (teamwork)

  8. Presentation of Later Modules
Module 2
Reliability Methodology, Part 2
  1. Boolean Modelling
    • System and function analysis
    • Function Block Diagram and Reliability Block Diagram (FBD and RBD)
    • Serial and parallel structures
    • Standby- and m-out-of-n structures
    • Reliability calculation of non-restorable systems
    • Application examples
    • Exercises

  2. Fault Tree Analysis (FTA)
    • Introduction
    • Development
    • Construction
    • Evaluation
    • Quantification
    • Common cause and common mode failure
    • Relations to other methods of reliability analysis
    • Some notes on tools
    • Description of the FTA documentation
    • Application examples
    • Exercises

  3. Event Tree Analysis (ETA)
    • Introduction
    • Development of event trees
    • Evaluation
    • Relationship with other reliability methods
    • Common cause and common mode failure
    • Description of the ETA documentation
    • Application examples
    • Exercises

  4. Derating
    • Introduction
    • Derating Development
    • Applications 1: switches, fuses, relays
    • Applications 2: connectors, capacitors, resistors, diodes, transistors
    • Applications 3: lamps, electrical motors, fans, circuit breakers, magnetic elements, tubes, thermistors, crystals/quartz, electrical EMI filters, microcircuits, hybrid microcircuits, micro-electro-mechanical elements, optoelectronic elements
    • Exercises

  5. Restorable Systems
    • Fundamentals of restorable systems
    • Quantitative reliability analysis
    • Application examples
    • Exercises

  6. Evaluating Incomplete Data
    • Approaches
    • Application examples
    • Exercises
Module 3
Reliability Methodology, Part 3
  1. Markov Modelling
    • State definition and state (transition) diagram
    • Formulating and solving differential equations
    • Evaluation of reliability measures
    • Application examples
    • Exercises

  2. Petri nets
    • Fundamentals (symbols, syntax, structure, and dynamic)
    • Reachability graph and state space
    • Structural properties (e. g. invariants, structural deadlock)
    • Temporal extensions to Petri nets
    • Modelling logical operators
    • Modelling simple item connections (serial connections; active, m-out-of-n, and stand-by redundancies)
    • Modelling maintenance tasks and strategies
    • Petri nets of fault and success trees
    • Petri nets of Markov chain/process state graphs
    • Application examples
    • Exercises

  3. Neural Networks
    • Introduction and biological analogies
    • Artificial neural networks
    • Neural network reliability data analysis
    • Predicting reliability by neural networks
    • Reliability growth modelling by neural networks
    • Other application areas
    • Neural fuzzy reliability approaches
    • Notes on genetic algorithms
    • Application examples
    • Exercises

  4. Simulations
    • Mathematical fundamentals of the Monte Carlo simulation
    • Evaluation of reliability data
    • Application of the Monte Carlo simulation to calculate input data uncertainties in reliability analysis
    • Application of the Monte Carlo simulation to evaluate the reliability of (mechanical) structures
    • Simulation tools
    • Application examples
    • Exercises

  5. Bayesian Approaches
    • Application of Bayesian approaches to reliability demonstration
    • Uniform and beta distribution as apriori information
    • Description of selected approaches
    • Discussion and comparison of the approaches
    • Application examples
    • Exercises
Module 8
Safety Analysis and Risk Assessment
  1. Fundamentals of Safety Analysis
    • Introduction
      • Description of deterministic (non-stochastic) concepts
    • Safety terminology: Terms and definitions
      • Safety and security
      • Hazard and danger

  2. Fundamentals of Risk Assessment
    • Introduction
      • Description of stochastic concepts
    • Risk terminology: Terms and definitions
      • Risk and chance
      • Acceptance and aversion
    • Risk representations
      • Risk matrix
      • Risk graph
      • Other risk representations
    • Presentation and comparison of risk acceptance concepts
      • GAMAB; GAME – Globalement Au Moins Aussi Bon; Globalement Au Moins Equivalent
      • MEM – Minimum Endogenous Mortality
      • ALARP – As Low As Reasonable Practicable
    • Application examples
    • Exercises

  3. Industrial-Sector-Specific Measures
    • Presentation and comparison of industrial sector-specific measures
      • Safety Integrity Level (SIL) according to IEC 61508
      • Design Assurance Level (DAL)
      • Performance Level (PL) according to ISO 13849-1 compared with EN 62061
      • Other measures
    • Assigning SILs, DALs, PLs
    • Summary

  4. Preliminary/Potential Hazard Analysis (PHA)
    • Introduction
    • Relations between the PHA and the Hazard List
    • Worksheet structure
    • Conducting a PHA
    • Hazard Log
    • Variants of PHA
      • Operating Hazard Analysis (OHA)
      • Maintenance Hazard Analysis
      • Other variants
    • Application examples
    • Exercises

  5. Failure Mode, Effects, and Criticality Analysis (FMECA)
    • Introduction
    • Risk and risk priority number
    • Relationship between FMECA and other methods of risk assessment
    • Failure rate, probability, and criticality number estimation
    • Report of FMECA
    • Applications
      • Use of FMECA
      • Application within a project
      • Limitations and deficiencies of FMECA
    • Application examples
    • Exercises

  6. Other Safety Analysis and Risk Assessment Methods
    • Discussion of the methods described in Modules 1 to 3
    • Methods for installation and process safety
      • Hazard and Operability Study (HAZOP)
      • What-if method
      • Zurich Hazard Analysis (ZHA)
      • Other methods
    • Collections of safety engineering methods
      • R.A. Stephens & W. Talso (System Safety Society)
      • FAA System Safety Handbook (Federal Aviation Administration)
      • SAE ARP 4761
    • Application examples
    • Exercises

  7. Probabilistic Safety Analysis resp. Probabilistic Risk Assessment (PSA/PRA)
    • Introduction
      • When to use PSA/PRA
      • Documenting decisions
      • Implementation of responsibility
    • PSA/PRA process
      • Definition of objective(s)
      • System familiarisation
      • Identification of initiating events
      • Scenario modelling
      • Failure modelling
      • Quantification
      • Uncertainty analysis
      • Sensitivity analysis
      • Ranking
      • Data analysis
    • PSA/PRA development requirements
      • Team
      • Implementation
      • Quality
      • Independent peer review
      • PSA/PRA as a living tool
    • Differences between PSA and PRA
    • Application examples
    • Exercises

  8. Safety Plan and Safety Case
    • Preparing a safety plan
    • Purpose of a safety case
    • Safety case scope
    • Safety case levels
    • Safety case phases
    • Safety case structure
    • Safety assessment
    • Interfaces with existing systems
      • Operation-proved systems
      • Unproved systems
    • Application examples