Design for Reliability

Chapter 14

Prognostics and Health Management Capabilities to Improve Reliability

Louis J. Gullo

Introduction

Prognostics and health management (PHM) capabilities are discussed in this chapter as they relate to reliable designs. Main topics covered include system health monitoring and health management for predicting failures and preventive maintenance actions, and improving design reliability with PHM through:

1. Preventive maintenance prior to failure

2. Condition-based maintenance to determine whether mission failure is imminent

3. Condition-based maintenance to predict failure occurrence

4. Corrective maintenance during and outside the mission window

Designing for prognostics capability ensures that failures are minimized during a mission when the product or system needs to operate failure-free. The prognostics capability accomplishes this goal by warning the user that a failure is imminent well in advance of the failure occurrence and manifestation of a severe or catastrophic failure effect. The prognostic capability is a form of condition-based maintenance (CBM) and development of preventive maintenance action to correct the failure in a proactive manner instead of a reactive manner. Also, maintenance costs can be reduced by allowing maintenance to be performed during planned shutdowns or less critical times when a mission is not being executed. By using PHM to reduce maintenance costs, the system experiences the advantages of increased inherent availability and operational ...