Reliability Engineering

18Health Monitoring and Prognostics

As a result of intense global competition, companies are considering novel approaches to enhance the operational efficiency of their products. For many products and systems, high in-service reliability can be a means to ensure customer satisfaction. In addition, global competitive demands for increased warranties, and the severe liability of product failures, is encouraging manufacturers to improve field reliability and operational availability,¹ provide knowledge of in-service use, and life-cycle operational and environmental conditions.

The American Heritage Dictionary defines prognostic as an adjective that relates to prediction or foretelling and as a noun for a sign or symptom indicating the future course of a disease or sign or forecast of some future occurrence. Hippocrates founded the 21 axioms of prognostics some 2400 years ago.² The goal of prognostics is to foretell (predict) the future health (or state) of a system. Health for human beings is defined as a state of complete physical, mental, and social well-being. These ideas can also be applied for the overall health or quality of products and systems. Interest has been growing in monitoring the ongoing health of products and systems in order to provide advance warning failure, and assist in administration and logistics. Here, health is defined as the extent of degradation or deviation from an expected normal condition. Prognostics is the prediction of the future state of health based ...