Practical Reliability Engineering and Analysis for System Design and Life-Cycle Sustainment: 1st Edition (Hardback) book cover

Practical Reliability Engineering and Analysis for System Design and Life-Cycle Sustainment

1st Edition

By William Wessels

CRC Press

497 pages | 347 B/W Illus.

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Hardback: 9781420094398
pub: 2010-04-16
eBook (VitalSource) : 9780429191817
pub: 2010-04-16
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In today’s sophisticated world, reliability stands as the ultimate arbiter of quality. An understanding of reliability and the ultimate compromise of failure is essential for determining the value of most modern products and absolutely critical to others, large or small. Whether lives are dependent on the performance of a heat shield or a chip in a lab, random failure is never an acceptable outcome.

Written for practicing engineers, Practical Reliability Engineering and Analysis for System Design and Life-Cycle Sustainment departs from the mainstream approach for time to failure-based reliability engineering and analysis. The book employs a far more analytical approach than those textbooks that rely on exponential probability distribution to characterize failure. Instead, the author, who has been a reliability engineer since 1970, focuses on those probability distributions that more accurately describe the true behavior of failure. He emphasizes failure that results from wear, while considering systems, the individual components within those systems, and the environmental forces exerted on them.

Dependable Products Are No Accident: A Clear Path to the Creation of Consistently Reliable Products

Taking a step-by-step approach that is augmented with current tables to configure wear, load, distribution, and other essential factors, this book explores design elements required for reliability and dependable systems integration and sustainment. It then discusses failure mechanisms, modes, and effects—as well as operator awareness and participation—and also delves into reliability failure modeling based on time-to-failure data considering a variety of approaches.

From there, the text demonstrates and then considers the advantages and disadvantages for the stress-strength analysis approach, including various phases of test simulation. Taking the practical approach still further, the author covers reliability-centered failure analysis, as well as condition-based and time-directed maintenance.

As a science, reliability was once considered the plaything of statisticians reporting on time-to-failure measurements, but in the hands of a practicing engineer, reliability is much more than the measure of an outcome; it is something to be achieved, something to quite purposely build into a system. Reliability analysis of mechanical design for structures and dynamic components demands a thorough field-seasoned approach that first looks to understand why a part fails, then learns how to fix it, and finally learns how to prevent its failing. Ultimately, reliability of mechanical design is based on the relationship between stress and strength over time. This book blends the common sense of lessons learned with mechanical engineering design and systems integration, with an eye toward sustainment. This is the stuff that enables organizations to achieve products valued for their world-class reliability.

Table of Contents


The Author

List of Tables

List of Figures

Requirements for Reliability Engineering: Design for Reliability, Reliability Systems Integration, and Reliability-Based System Sustainment


Part Reliability

Failure Mechanisms

Failure Modes

Failure Effects—Local Failure Effects—Next Higher Failure Effects—System (End Effect) Failure Modes and Effects Analysis Criticality Analysis System End Effects P–F Interval Operator Awareness of Degradation

Maintainability and Maintainability Engineering

Fault Detection

Fault Isolation

Part Mean Time to Repair

Administrative and Logistical Downtime

Part and System Availability

Reliability in an Organization

The Need for Change in Conventional Organizational Structure

Proposed Organization Structure

Design for Reliability: Reliability Engineering Requirements for Part Design

Design Requirement for a System

Systems Engineering Work Breakdown Structure

Lowest Replaceable Unit, LRU, Reliability Allocations

Conditions of Use, Mission Duration, and Maintainability Allocations

Functional Design Analysis

Functional Reliability Block Diagram

Functional LRU Failure Modes and Effects Analysis

Functional LRU Criticality/Consequences Analysis and Critical Items List

Design Trade Studies

LRU Nondestructive Examination and Math Modeling

Preliminary LRU Failure Mechanisms: Modes and Effects Analysis

Preliminary LRU Criticality/Consequences Analysis and Critical Items List

Preliminary Design Bills of Materials and Drawings

Preliminary Reliability Block Diagram and Math Modeling

Preliminary LRU Reliability, Maintainability, and Availability Estimates

Design Tests and Evaluation

Reliability Experiments and Math Modeling

Design LRU Failure Mechanisms Modes and Effects Analysis

Design LRU Criticality/Consequences Analysis and Critical Items List

Final Design Analysis, Bills of Materials, and Drawings

Final Design Reliability Block Diagram and Math Modeling

Final LRU Failure Mechanisms Modes and Effects Analysis

Design Reviews

Reliability Systems Engineering Requirements for System Integration

Part/LRU-to-Assembly Integration

Part/LRU-to-Assembly Reliability, Maintainability, and Availability Model

Assembly Design Review

Design Modification

Reliability Growth

Assembly-to-Subsystem Integration

Assembly-to-Subsystem Reliability, Maintainability, and Availability Model

Design Review

Design Modification

Reliability Growth

Subsystem-to-System Integration

Subsystem-to-System Reliability, Maintainability, and Availability Model

Design Review

Design Modification

Reliability Growth

System Demonstration

Reliability and Maintainability Demonstration

System Baseline

Configuration Management

Reliability Engineering Requirements for System Sustainment

System Sustainment

Repair Maintenance

Logistical Support

Database Requirements


Part/LRU Reliability Modeling for Time-to Failure Data


Part Candidate for Reliability Engineering and Analysis

Hypothesize Part Failure Mechanisms

Part Failure Modes Analysis

Part Failure Effects Analysis

Critical Items List

Part/LRU Reliability Analysis: Understanding Failure of a Part/LRU

Qualitative Part/LRU Investigation

Part/LRU Design Parameters Fall in One of Three Criteria

Quantitative Part/LRU Investigation

TTF and TTR Frequency Distribution and Probability Density

Function of Part/LRU Failure

Cumulative Frequency Distribution

TTF Survival Function of a Part/LRU

TTF Instantaneous Part/LRU Failure Rate: The Hazard Function.3

TTF Reliability Function of a Part/LRU

Part/LRU Time-to-Failure Characterization of Reliability Parameters

Part/LRU Historical Part Failure Data

Part/LRU Reliability Experiments

Time-Censored Experimental Part/LRU Failure Data

Interval-Censored Experiment

Failure-Censored Experimental Part/LRU Failure Data

Failure-Free Experimental Part Data

Maintainability Analysis Functions of a Part/LRU

Resource Requirements for a Part/LRU

Inherent Availability of a Part/LRU


Reliability Failure Modeling Based on Time-to-Failure Data


Part Reliability Failure Modeling

Candidate for Reliability Engineering and Analysis

Experimental Design for TTF

Exponential Probability Distribution Approach

Spreadsheet Approach

Exponential Distribution: Minitab

Weibull Distribution Approach

Spreadsheet Approach

Weibull Distribution: Minitab

Weibull Distribution: MathCAD Approach

Pump Failure Math Model

Triangular Distribution


Part Maintainability and Availability


Part Mean Time to Repair

Maintenance Experiment

Excel Spreadsheet Approach

Minitab Approach

MathCAD Approach

Empirical Data

Part and System Availability

Inherent Availability

Instantaneous Availability

Operational Availability

Achieved Availability


Part Reliability Based on Stress-Strength Analysis


Part Stress

Part Failure

Time-to-Failure Reliability Functions

Example TTF Reliability Functions for Hex Bolt

Exponential Failure Distribution Approach

Single Failure Mechanism Weibull Model Approach

Multiple Failure Mechanism Weibull Model Approach

Comparative Evaluation of Exponential, Single Weibull, and Multiple Failure Mechanism Weibull Model Approaches Using TTF Data

Part Stress and Strength: Interference Theory

Normal Stress–Normal Strength Normal Stress–Weibull Strength Weibull Stress–Weibull Strength Triangular Stress–Weibull Strength Stress-Strength Reliability of the Bolt in Tension and Shear Nondeterministic, Variable Approach Advantages and Disadvantages for Stress-Strength Analysis Approach


Reliability Engineering Functions from Stress-Strength Analysis


Frequency Distributions of the Mechanisms of Failure

Design for Reliability

Phase I: 1-Operational-Day Test Simulation Period

Phase II: 1-Operational-Year Test Simulation Period

Phase III: 2-Operational-Year Test Simulation Period

Design for Reliability by Analysis

Material in Tension


Failure Modeling Based on Failure Mechanisms


Normal Distribution Stress–Normal Distribution Strength1

Normal Distribution Stress–Weibull Distribution Strength

Weibull Distributed Stress–Weibull Distribution Strength

Triangular Distribution Stress–Triangular Distribution Strength


Reliability Modeling for Assembly Design Levels


Reliability Allocation

Reliability Math Model

Math Modeling for Design Configurations of Assemblies

Series Design Configuration

Parallel Design Configuration

n-Provided, r-Required Redundancy

Standby Redundancy

Equal Reliability: Perfect Switch

Unequal Reliability: Perfect Switch

Equal Reliability: Imperfect Switch

Unequal Reliability: Imperfect Switch

Shared Load Redundancy7


Reliability Analysis for System of Systems


Multiple-Missions System of System

Simple Single-Mission System of Systems

Complex Single-Mission System of Systems

System of Systems Compared


Reliability-Centered Maintenance


Implementation of Reliability-Centered Maintenance


Reliability-Centered Failure Analysis


Nondestructive Examination, Design, and Destruct Limits

Condition-Based Maintenance NDE

Time-Directed Maintenance NDE

Finite Element Math Model, Simulation and Analysis, Design Loads and Material Design Properties, Statistically Significant Failure Mechanisms

No Maintenance Solution

CBM Solution

TDM Solution

Physical Test

Highly Accelerated Life Test


Method 501: High Temperature

Method 502: Low Temperature

Method 503: Temperature Shock

Method 507: Humidity

Method 514: Vibration

Method 520: Combined Environments (Temperature, Vibration, and Humidity)

Accelerated Life Testing

Time Compression Accelerated Life Testing

Life-versus-Stress Analysis Accelerated Life Test

Condition-Based Maintenance


CBM Logic

Maintainability Demonstration Test, Validate Part Fault Detection, and P–F Interval

Develop and Implement Maintenance Procedures and Practices.20


Time-Directed Maintenance


Characterize Hazard Function

Define Hazard Threshold

Maintainability Demonstration Test, Validate Hazard Function

Develop and Implement Maintenance Procedures and Practices



Subject Categories

BISAC Subject Codes/Headings:
SCIENCE / Mechanics / General
TECHNOLOGY & ENGINEERING / Industrial Design / General