《5.SMA》.pdf

Smart Materials and Structures 5. Shape Memory Alloy Materials 5. Shape Memory Alloy Materials • Introduction and History • How SMA Works • Transformation Hysteresis • Stress-Strain Relationship • Superelasticity • Types of Shape Memory Alloy Materials • Shape Memory Alloy Properties • A Constitutive Model of SMA DaLian University of Technology Dr. Song 11111 Smart Materials and Structures 5. Shape Memory Alloy Materials Introduction Example of Shape Memory Alloys (SMAs) DaLian University of Technology Dr. Song 22222 Smart Materials and Structures 5. Shape Memory Alloy Materials Introduction • Shape Memory Alloys (SMAs) are novel metal materials which have the ability to return to a predetermined shape when heated. • When an SMA is cold, or below its transformation temperature, it has a very low yield strength and can be deformed quite easily into any new shape. However, when the material is heated above its transformation temperature SMA Spring it undergoes a change in crystal structure which causes it to After being Elongated at Cold return to its original shape. • If the SMA encounters any resistance during this transformation, it