CAUSES OF FAILURES

Every failure has a well-defined cause.  Any system or device has an inherent strength or capacity to resist failures. This depends on design, material, manufacturing, quality assurance and maintenance. Operational as well as environmental stresses always act on the system. The system will survive as long as the inherent strength is more than the stresses. Whenever the stress value increases beyond the limits (or strength decreases due to ageing) the system will fail.  In industrial mass production, both stress and strength of products vary considerably  from their  nominal  values  and  can  be  described/  characterised through statistical distributions.

Poor design, inadequate manufacturing techniques, wrong material selection, lack of total knowledge and experience, complexity, poor maintenance, rough usage, improper environmental control, organizational rigidity, and human error are some of the common causes of failures.