applications and develop improved processing techniques and structures. Materials encompasses in different types of areas, it is often divided according to types of materials like metals, ceramics, polymers, and semiconductors. Material has to many applications such as biomaterials, electronic materials, magnetic materials, structural materials. Smart materials are designed materials that have one or more properties that can be significantly changed in a controlled by external boost such as stress, temperature, moisture, pH, electric or magnetic fields. Smart materials have been around for many years and they have found a large number of applications.
The use of the terms ‘smart’ and ‘intelligent’ to describe materials and systems came from the United States and started in the 1980’s despite the fact that some of these so-called smart materials had been around for decades. Many of the smart materials were developed by government agencies working on military and aerospace projects but in recent years their use has transferred into the mechanical and civil engineering sector for applications in the automotive, construction, transport, medical, leisure and domestic areas. Smart material system which has intrinsic sensor, actuator and control mechanisms whereby it is capable of sensing a stimulus, responding it and reverting to its original state after the stimulus is removed. Smart materials are also called as functional materials. A material can be considered smart when an input stimulus of a variable changes the output of other variables not given as input.
There are many groups of smart materials each exhibiting particular properties which can be used in a variety of high-tech and everyday applications. These include shape memory alloys, piezoelectric materials, magneto-rheological and electro-rheological materials, magneto strictive materials and halochromic materials, pH sensitive polymer, smart inorganic materials, temperature responsive polymers, ferrofluid, photomechanical materials, polycaprolactone, self-healing materials, die-electric elastomers, which change their color in reaction to various stimuli. The distinction between a smart material and a smart structure should be emphasized. A smart structure incorporates some form of actuator and sensor which can be made from smart materials. It controls hardware and software to form a system which reacts to its environment. Like a structure of an aircraft wing which continuously alters its profile during flight to give the optimum shape for the operating conditions at the t