Page 263 - Handbook of Materials Failure Analysis

CHAPTER

The reliability design of

mechanical system and its 11

parametric accelerated life

testing

Seong-woo Woo
Korea Testing Co., Daejeon City, South Korea

CHAPTER OUTLINE
1 Introduction ..................................................................................................... 259
2 Design Verification Activities in R&D, QA (Performance/Reliability), and
Manufacture QC and Their Traps ....................................................................... 261
3 Reliability Quantitative Specifications ............................................................... 263
4 Conceptual Framework of Specifications for Quality Assurance ........................... 267
5 Case Study of Verification Specification: Robotics ............................................. 268
6 Parametric Accelerated Life Testing .................................................................. 270
6.1 Accelerated Factor ...........................................................................272
6.2 Sample Size Equation ......................................................................273
7 Conclusion ....................................................................................................... 274
References ............................................................................................................ 275

1 INTRODUCTION
For mechanical systems, robust design techniques [1–4] were developed by statisti-
cians many years ago. Robust design processes include concept design, parameter
design, and tolerance design. Taguchi’s robust design method uses parameter design
to place the design in a position where random “noise” does not cause failure and to
determine the proper design parameters and their levels. The basic idea of parameter
design in the Taguchi’s robust design is to identify appropriate settings of control
factors that make the system’s performance robust in relation to changes in the noise
factors. Thus, the control factors are assigned to an inner array in an orthogonal array,
and the noise factors are assigned to an outer array.
However, a large number of experimental trials in the Taguchi product array may
be required because the noise array is repeated for every row in the control array. For
a simple mechanical structure, a lot of design parameters should be considered in the
Taguchi method’s robust.

Handbook of Materials Failure Analysis With Case Studies from the Chemicals, Concrete, and Power Industries. 259
http://dx.doi.org/10.1016/B978-0-08-100116-5.00011-9
Copyright # 2016 Elsevier Ltd. All rights reserved.