ABSTRACT

Reliability assessment and its associated validation techniques are crucial factors in the success of any engineering hardware. Hardware reliability is often defined as the probability that the equipment will perform throughout the intended mission life within specified tolerances under specified life-cycle loads. (Here, the term includes all external influences that can affect hardware performance-for example, mechanical forces, temperature, time, concentrations of harmful chemicals, radiation, and electrical voltage/current.) The purpose of reliability assessment is to provide criteria for selecting courses of action that affect (and are affected by) reliability. Reliability is not a matter of chance; it has to be consciously and actively built into hardware through careful specification of good design and manufacturing practices. Proactive, quantitative reliability assessment during the design phase can be an effective vehicle for a variety of other design functions, such as

Failure of hardware is due to complex sets of interactions between (1) the “stresses” (i.e., environmental parameters that act on and within the module) and (2) the materials and configurations of components, interconnects, and assemblies. A proper evaluation of reliability requires a systematic analysis of the response of the materials and configurations to the “stresses.” From the viewpoint of physics of failure, the characteristics of the failures of a product should be defined by the failure mode, failure site, and failure mechanism.