1.5.1. Application of shape memory alloy in Automobile:

1.5.1.1. Thermal actuators :It respond to changes in temperature by changing their shape and bygenerating a force. Thermal actuators havea variety of applications in cars. Figure 2 schematicallyshows areas of both potential and realized applicationsfor shape memory thermal actuators.

Fig 2 Potential applications of shape memory thermal actuators in automobiles: (1) radiator shutler; (2) {andutch; (3) fuel management; (4) climate control; (5) engine control; (6) brake ventilation; (7) transmissioncontrol/rattling noise reduction; (8) suspension adjustment

1.5.1.2. Electrical actuators:

Electrical actuators are devices which perform a task ondemand. The stimulus is any voltage applied to thedevice, which is usually an electric motor or a solenoid.If electrically heated above A., such as by passingcurrent through a wire or spring, Ni·Ti shape memoryelements become electrical actuators. They can provideinteresting advantages over motors and solenoids like:• small size• noiseless operation• few mechanical partsTherefore an almost unlimited number of potentialapplications can be found in the patent literature.

1.5.2. Impact Protection & Regaining Of Origianl Shape In Automobile:

1.5.2.1. Impact Protection:

System for cars that can detect side-coming impacts. Once scientists can create a system that can correctly detect and react to impacts,shape-memory alloys will be used to make the impact safer for passengers. The idea is to use shape-memory alloys in vehicles so thatthe car can alter its physical shape slightly when an impact has been detected to decrease the chance of injury to any of the passengers .

1.5.2.2. Regaining of original shape:

The use of shape-memory alloys in cars would also make it much easierto fix a dented door or bumper on a car. If a dent was detected in theside of the car, the cars computer could send an electric current through the metal and it would return to its original shape. Not onlycan SMAs be reverted back to their original shape by heat, but also by a specific amplitude of electric current.

1.5.3. Aero space applications:

Utilization of both the shape memoryand pseudoelastic effects of SMAs in solving engineering problems in the aerospace industry. Such implementations of SMA technology have spanned the areas of fixed wing aircraft, rotorcraft, and spacecraft.

1.5.3.1. Fixed-Wing Aircraft and Rotorcraft Applications which apply specifically to the propulsion systems and structural configurations of fixed-wing aircraft will firstbe considered. Perhaps two of the most well-known fixed-wingprojects of the past are the Smart Wing program and the SmartAircraft and Marine Propulsion System demonstration (SAMPSON).

Total and cut-away view of the SMA torque tube as installed inthe model wing during the SMART Wing project .

1.5.3.2. Spacecraft ApplicationsSpace applications are those which seek to address the unique problems of release, actuation, and vibration mitigation during either the launch of a spacecraft or its subsequent operation in a micro-gravity and zero-atmosphere environment. Whileactuated structures in space are subject to low gravitational forces which reduce required actuator power, heat transfer can quickly become problematic due to the lack of a convective medium. Itshould be noted that for most designs described below, little or no modeling of the SMA behavior was performed.

Detail of hinges, folded and deployed configuration

1.5.4.Application of shape memory in Frangibolts:

Use in space was an early predicted application and continues to grow. One form of separation device, the Frangibol, has been used on numerous space missions.

Frangibolt Frangibolt separation system. consists of an electric heater surrounding a hollow cylinder of TiNi and a specially-notched bolt. The TiNi actuator is prepared by compressing it 5 percent of its length, then securing it through the TiNi cylinder with a nut: a payload is secured for launch. To deploy the payload, electric power heats the TiNi actuator cylinder, it expands and elongates the notched bolt to fracture.

References:

Shape Memory Actuators for Automotive ApplicationsStoeckel“Engineering Aspects of Shape Memory Alloys”(eds.) T.W. Duerig, K.N. Melton et al.1990

AEROSPACE APPLICATIONS OF SHAPE MEMORY ALLOYSDarren HartlDimitris C. Lagoudas _Aerospace Engineering DepartmentTexas A&M UniversityCollege Station, Texas 77843-3141

STATE-OF-THE-ART OF SHAPE MEMORY ACTUATORS A. D. Johnson TiNi Alloy Company, San Leandro, CA, USA