Experimental Investigation of Mechanical Properties of Nitinol, Structural Steel, and Their Hybrid Component

Usage of special materials with unique properties in seismic resistant structures has increased to overcome their limited energy dissipation and ductility as a result of the 1994 Northridge earthquake. Among them, shape memory alloy (SMA) is a unique metallic alloy that has the ability to undergo large deformation while reverting back to its original undeformed shape; but because any new technology has its pros and cons together, using SMA in structures is not all benefit. In this paper, advantages and disadvantages of using shape memory alloys in structures are studied according to experimental results. Monotonic and cyclic static loading tests on Nitinol and steel bars are conducted to obtain their mechanical properties in tension and compression. Also, a comparative low-cycle fatigue test is conducted using steel and Nitinol samples. Considering the results, a simple and practical solution is developed to overcome some of the deficiencies of these two materials in seismic resisting structures.