Shape Memory Alloys (SMAs) based Composites for Automotive Crashworthiness Applications

Smart materials have brought a radical scientific shift in engineering design, mostly for highly functional and lightweight intelligent systems. Shape memory alloys (SMAs) are a class of smart materials with several wide range applications as components of adaptive structures. Due to their capability of crystallographic transformation between austenite and martensite phases, SMAs can undergo large reversible deformations under loading or thermal cycles and generate high thermomechanical driving forces. Integration of SMAs into composite materials has become one of key routes to take advantage of the extraordinary properties of such materials with a reduced cost. In this direction, SMAs in the form of long fibres (wires), ribbons, short fibres, and particles are often used as reinforcements in composites. Automotive applications is considered one of the first massive exploitations using SMA materials. Furthermore, SMAs reinforced polymer composites may offer a multitude of benefits and enormous potentials for automobile and energy-absorbing applications under the dominant role of lightweight materials. However, successful adoption of SMA composites for automotive structural components has yet to be achieved. Within this perspective, this paper represents a review that describes the potentials and possible designs for an automotive crash box and bumper system using SMAs and SMAs-based composites to improve the impact response and energy absorption. A full-structure bumper system is further simulated to illustrate the energy absorption of composite-based SMAs and effect of SMA addition on automotive's crashworthiness.