Reliability Engineering

This textbook covers the fundamentals of reliability theory and its application for engineering processes, especially for aircraft units and systems. Reliability basis was explained for the best understanding of reliability analysis application for engineering systems in aviation industry. Several approaches for the reliability analysis and their application with examples are presented. It also introduces main trends in the modern reliability theory development. This book will be interested for university students and early-career engineers of aviation industry majors. Preface 5 Contents 7 1 Introduction 12 1.1 Basic Concepts of Reliability Theory 12 1.2 Main Indicators of Reliability 15 1.2.1 Failure-Free Indicators 16 1.2.2 Durability Indicators 16 1.2.3 Indicators of Maintainability and Preservation 17 1.2.4 Complex Indicators 17 1.3 Base Dependencies of the Reliability Theory 17 1.4 Reliability During Regular Operation 20 1.5 Reliability During Gradual Failures 23 1.5.1 The Normal Distribution 23 1.5.2 The Truncated Normal Distribution 27 1.5.3 In a Log-Normal Distribution 28 1.5.4 The Weibull Distribution 30 1.6 Combined Action of Sudden and Gradual Failures 33 1.7 Features of the Reliability of Recoverable Products 34 1.8 Questions 35 References 36 2 Mathematical Basis of Reliability 37 2.1 Introduction 37 2.2 Random Events and Probabilities 37 2.3 Numerical Features and Distributions of Random Variables 40 2.3.1 Mathematical Expectation 40 2.3.2 Dispersion 41 2.3.3 Average Square-Law Deviation 42 2.3.4 Moments of Distribution 42 2.3.5 Asymmetry 43 2.3.6 Excess 44 2.3.7 Mode of Discrete Random Variable 44 2.3.8 Median of Random Variable 45 2.4 Distribution Functions of Random Variables 45 2.4.1 Distribution Functions for Discrete Random Variables 45 2.4.2 Distribution Functions for Continuous Random Variables 47 2.5 Questions 51 References 52 3 System Reliability Models 53 3.1 Introduction 53 3.2 Non-repair System Reliability Analysis 54 3.2.1 Classification of System Reliability Function 54 3.2.2 Analysis of the Reliability Function 55 3.2.3 Redundancy System Reliability 59 3.2.4 Methods of the Reliability Function 63 3.3 Repair System Reliability Analysis 67 3.3.1 General Information 67 3.3.2 System Reliability Function 73 3.3.3 Non-parametric Analysis Methods 85 3.3.4 Parametric Analysis Methods 95 3.3.5 Markov Chain and Its Application 110 3.4 Questions 132 References 133 4 Complex System Reliability Analysis Methods 134 4.1 Introduction 134 4.2 Failure Mode and Effect Critical Analysis 135 4.2.1 Basic Concepts 135 4.2.2 Types of FMECA 136 4.2.3 Steps for FMECA 137 4.2.4 Criticality Assessment 140 4.2.5 FMECA Application 144 4.3 Fault Tree Analysis 148 4.3.1 Basic Concepts 149 4.3.2 Basic Approach 151 4.3.3 Qualitative Analysis 154 4.3.4 Quantitative Analysis 156 4.3.5 Reliability Graph 165 4.3.6 FTA Application 166 4.4 Comparison FMECA and FTA 168 4.5 Questions 169 References 170 5 Model-Based Reliability Analysis Methods 171 5.1 Introduction 171 5.2 Multi-Source Reliability Data Processing System for Mechanical Parts 172 5.2.1 Comprehensive Reliability Assessment Model Based on Multi-Source Data 173 5.2.2 Case Study 178 5.3 Multi-Phase Mission Reliability Analysis 182 5.3.1 PMS System Characteristics 182 5.3.2 PMS Reliability Modeling Process 183 5.3.3 Static Reliability Analysis Method Based on BDD 184 5.3.4 Dynamic Reliability Analysis Method Based on Semi-Markov 190 5.3.5 Modular Analysis Method 193 5.3.6 Case Study 193 5.4 Conclusions 199 References 200 6 System Reliability Prediction and Allocation 201 6.1 Introduction 201 6.2 Reliability Prediction 202 6.2.1 Reliability Block Diagram 202 6.2.2 Series Systems 203 6.2.3 Parallel Systems 207 6.2.4 Combined Structure 209 6.2.5 k-Out-of-n Systems 212 6.2.6 Redundant System 215 6.2.7 Reliability Evaluation of Complex Systems 220 6.2.8 Confidence Ranges for System Reliability 225 6.2.9 Component Importance 234 6.3 Reliability Allocation 240 6.3.1 Criteria for Reliability Allocation 241 6.3.2 Equal Allocation Approach 242 6.3.3 ARINC Approach 243 6.3.4 AGREE Allocation Approach 245 6.3.5 Customer-Driven Allocation Approach 248 6.3.6 Optimal Allocation Approaches 250 6.4 Questions 252 References 253 7 Mechanical Reliability Analysis 254 7.1 Introduction 254 7.2 Basic Concepts 255 7.2.1 Types of Operational Loads 255 7.2.2 Specifics of Static Load 256 7.2.3 Specifics of Cycling Loading 258 7.2.4 Specifics of Temperature Effect 262 7.2.5 Creep and Relaxation of Stresses 266 7.3 Factors Affect Mechanical Reliability 268 7.3.1 Corrosion 268 7.3.2 Chemical Medium 270 7.3.3 Fields Environment 271 7.3.4 Space Medium 273 7.3.5 Structural Materials’ Selection 274 7.4 Short Observe of Structural Elements 276 7.5 Probabilistic Calculations of Machinery Parts 279 7.5.1 Some Aspects of Probability Theory for Machinery Parts 280 7.5.2 Specifics of Probabilistic Strength Computing of Shafts and Axles 283 7.5.3 Computing Examples for Various Machinery Components 286 7.6 Civil Aircraft Jettison Fuel Subsystem Reliability Analysis 291 7.6.1 Background for the Computation 291 7.6.2 Risks and Challenges of Aircraft Fuel Jettison Subsystem 295 7.6.3 Function Hazard Assessment 296 7.6.4 Primary System Safety Assessment Facing on Reliability Distribution 299 7.6.5 Reliability Analysis of Each Independent Fuel Tank for Dumping 305 7.6.6 Reliability Analysis of the Whole Fuel Jettison Subsystem 309 7.7 Conclusions 311 7.8 Questions 312 References 312 8 Reliability Tests 314 8.1 Introduction 314 8.1.1 Targets of Reliability and Life Tests 315 8.1.2 Specifics of Life Tests and Reliability 316 8.1.3 Test Types 317 8.1.4 Test Planning and Documentation 322 8.2 Reliability Tests Plan 324 8.2.1 Types of Tests 325 8.2.2 Test Samples 327 8.2.3 Test Stresses 327 8.2.4 Test Time 328 8.3 Zero-Failure Test 329 8.3.1 Binomial Zero-Failure Testing 330 8.3.2 Weibull Zero-Failure Testing 332 8.4 Life Tests 336 8.4.1 Theoretical Concept 336 8.4.2 Binomial Series Life Testing 339 8.4.3 Exponential Series Life Testing 344 8.4.4 Weibull Series Life Testing 346 8.5 Accelerated Tests 348 8.5.1 Principles for Accelerating Tests 348 8.5.2 Operational Cycles Compressing 349 8.5.3 Extrapolation in Time 350 8.5.4 Revision of Loading Range 351 8.5.5 Increased Frequency of Operational Cycles 352 8.5.6 Loading Extrapolation 352 8.5.7 Break Completely 354 8.5.8 Progressive Load Forcing 354 8.5.9 Alternating Modes Loading 357 8.5.10 Some Specifics of the Accelerated Tests 360 8.6 Verification of Reliability Based on Prior Information 361 8.7 Verification of Reliability by Means of Degradation Tests 363 8.8 Questions 365 References 366 9 Risk Analysis of Aircraft Structure and Systems 367 9.1 Introduction 367 9.2 Risk Assessment of Aeroengine Life-Limited Parts 368 9.2.1 ELLPS Airworthiness Regulations and AC Analysis 369 9.2.2 Determination Method of ELLPs Based on FMEA 374 9.2.3 Probabilistic Risk Assessment of ELLPs 379 9.2.4 Case Analysis 388 9.3 Risk Warning of Aircraft Bleed Air System 392 9.3.1 Risk Warning Method 393 9.3.2 Application of Risk Warning on the BAS 400 9.4 Conclusions 417 References 419