Reliability Concepts and Reliability Data

Reliability Concepts and Reliability Data Objectives

• Explain basic concerns relating to product reliability.
• List some reasons for collecting reliability data.
• Describe the distinguishing features of reliability data.
• Provide examples of reliability data and describe the moti-
vation for the collection of the data.
• Outline a general strategy that can be used for data analysis, modeling, and inference from reliability data.

Quality and Reliability

New pressures on manufacturers to produce high quality products. Pressures due to:
• Rapid advances in technology.
• Development of highly sophisticated products.
• Intense global competition.
• Increasing customer expectations.

Reasons for Collecting Reliability Data

• Assessing characteristics of materials.
• Predict product reliability in design stage.
• Assessing the effect of a proposed design change.
• Comparing two or more different manufacturers.
• Assess product reliability in field.
• Checking the veracity of an advertising claim.
• Predict product warranty costs.

Definitions of Reliability

• Technical: Reliability is the probability that a system, vehicle, machine, device, and so on, will perform its intended function under encountered operating conditions, for as pecified period of time.
• Succinct: Reliability is quality over time (Condra 1993).

Other Common Names for Reliability Data

• Life data.
• Failure-time data.
• Survival data.
• Event-time data.
Also, degradation data (somewhat different).