Damages like matrix cracking, delamination, debonding or fiber breakage in composite structures are unavoidable during service life time due to impact or continual load, chemical corrosion and aging, change of ambient conditions, etc. Many times, it is not feasible to take the structure out of use (such as buildings, bridges and other big structures). Further, the lack of global integration capability of the present day non-destructive evaluation methods result in longer downtime, inconvenience and enhanced cost of maintenance. Real time damage detection and health monitoring in such cases have become one of the main areas of focus today. In recent years efforts have been made at developing structures that can sense and control their own damage by using a network of distributed sensors and actuators. With the improvement in sensing and actuation technologies and their availability in the form of sensor patches e.g. PZT patches, PVDF films, magnetostrictive materials like Terfenol-D in the form of thick films or in particulate form and the feasibility of embedding them into or bonding those to composite structures is leading to growth of a new concept known as smart / intelligent structure. This concept is emerging to be attractive for potential high performance structural applications and other critical and advanced applications.