Design Reliability

Dein Shaw

PME, Tsing Hua University

Chapter 1 Introduction

1.1 Reliability history

• German V1, V2 rocket World war II

• Electronic tube Aeronautic radio, Inc, 1947

• …….

1.2 Need of reliability in product design

• Huge amount of the parts are used for a complicate system.

eg. $1 for design stage$ 10 after final release $100 at prototype$1000 at pre-production stage$10000 at production stageDesign relate problems are greatest causes for pro

duct failure. 43% due t design, 30% operation and maintenance, 20% manufacturing, 7% miscellaneous factors

Reliability in the product design process

Reliability tasks:1. Establishing reliability requirements definition2. Using reliability design standards/guides/checklist3. Allocation reliability4. Predicting reliability5. Reliability modeling6. Monitoring subcontractor/supplier reliability activities7. Performing failure modes effects and criticality analysis8. Monitoring reliability growth9. Accessing software reliability10. Environmental stress screening11. Preparing critical items list12. Performing electronic parts/circuits tolerance analysis

Reliability specialized and application areas

1. Mechanical reliability2. Software reliability3. Human reliability4. Reliability optimization5. Reliability growth6. Structural reliability7. Reliability general8. Power system reliability9. Robot reliability and safety10. Life cycle coasting11. Maintainability

Term and definition

1. Reliability2. Failure3. Maintainability4. Redundancy5. Active redundancy6. Availability7. Mean time to failure (exponential distribution)8. Useful life9. Mission time10. Human error11. Human reliability

1.3 Pattern of Failure

1.3.1 component failure

Example 1.1 automobile break (measured in miles of successful operation)

Show relative frequency diagram:

As will shown later, the standard deviation indicates a measure of the spread out of the life of break.

1.4 Factor of Safety and reliability

S=150k(lb/in2), L=75k(lb/in2)

Problem:

Find the U.S. military standard which are relate to reliability.