Chapter 12 - Topics in Reliability

Abstract

This chapter describes the fundamental aspects of reliability, directly or indirectly relating to maintainability. The objective of both reliability and maintainability is to assure that the system or equipment manufactured will be in a state of readiness for operation when required, capable of carrying out its designated functions effectively, and able to meet all the required maintenance characteristics during its life span. Reliability is an important factor in engineering system designs. Its history goes back to the 1930s when probability concepts were applied to the problems of electric power generation. However, usually, World War II, when Germans applied basic reliability concepts to improve the reliability of their V1 and V2 missiles, is regarded as the real beginning of the reliability field. Between 1945 and 1950, the United States Air Force, the Navy, and the Army performed various studies on the failure of electronic equipment, equipment repair, and maintenance cost. As a result of their findings, the Department of Defense formed an ad hoc group in 1950 on reliability of electronic equipment. Two years later, this group became known as the Advisory Group on the Reliability of Electronic Equipment (AGREE). In 1957, the group published a report that included the requirements for reliability tests, the effects of storage on reliability, and the minimum acceptability limits. The report was instrumental in setting specifications for the reliability of military electronic equipment. Since the 1950s, the reliability field has developed into many specialized areas, such as mechanical reliability, software reliability, human reliability, and power system reliability.