Design for Reliability

Chapter 5

Design Failure Modes, Effects, and Criticality Analysis

Louis J. Gullo

Introduction to FMEA and FMECA

Failure modes and effects analysis (FMEA) is a complex engineering analysis methodology used to identify potential failure modes, failure causes, failure effects and problem areas affecting the system or product mission success, hardware and software reliability, maintainability, and safety. FMEA provides a structured process for assessing failure modes and mitigating the effects of those failure modes through corrective actions. When FMEA is performed on hardware in collaboration with the electrical circuit designer or the mechanical design engineer, it is very useful in effecting design improvements. The success of FMEA depends on collaboration between the FMEA analyst and the designers and stakeholders. This involves conducting open dialogue sessions, which are especially valuable in uncovering and resolving single-point failure modes at discrete levels of the system or product design that have an unacceptably high probability of occurrence or a critically severe failure effect that causes personnel injury or high system repair cost due to loss of system functionality. Elimination of single-point failures is one of the primary concerns of an analyst performing FMEA. For key findings, design changes should be incorporated to reduce the severity of the failure effects or to minimize the probability of occurrence of the particular failure mode or to increase the detectability ...