## 2 Shape Memory Alloys (SMAs)  
SMAs are intelligent materials with exceptional properties. SMAs have complex thermo-dynamical behavior, which is related to the various physical processes. The well-known properties of these materials are super-elasticity and the shape memory effect ([PERSON] and [PERSON] [30]). In terms of their super-elastic behavior, the strain due to dynamic loads can be recovered entirely after unloading. However, in the shape memory effect, the dynamic deformation of these materials can return to their initial shape by heating. SMAs are widely used in civil engineering applications because of their high damping capacity, erosion resistance, and fatigue strength. SMAs have two phases with different crystal structures. The first phase is named martensite, which is stable at low temperatures and high stresses. The other phase is austenite, which is stable at high temperatures and low stresses. Based on the directions of the crystals, the martensite phase is divided into two shapes: Twinned martensite and detwinned martensite. Four specific temperatures are introduced to show the temperature range of the start and finish of these phase transformations. \(M_{\mathrm{s}}\) is the temperature at which the transition from austenite to martensite starts, and \(M_{f}\) is the temperature at which the martensite phase is completed. Furthermore, \(A_{\mathrm{s}}\) and \(A_{f}\) are the temperatures at which the transformation from martensite to austenite starts and finishes, respectively ([PERSON] [31]). The unusual properties of SMAs are the products of returnable transformation between austenite and martensite. It is worthwhile to mention that the atoms' arrangement remains without change during this transformation, and it occurs because of the shear deformation of the grid structure of these materials. This paper aimed to take advantage of the super-elastic property of SMA in which austenite transforms to martensite and transforms backward. In this way, the residual deformation can be completely recovered in a cyclic process, which leads to energy dissipation. This cycle is illustrated in Figure 1. An SMA should entirely be in its austenite phase to be able to behave super-elastically. In other words, if the temperature of the SMA is higher than the temperature at which the austenite phase finishes, the induced strain (less than the maximum super-elastic strain) can be completely recovered. Therefore, an SMA, whose \(A_{f}\) is less than the minimum temperature of the surroundings, should be selected. Since [PERSON] first found Nitinol in 1963, various types of shape memory alloys have been presented ([PERSON] [32]). The most common ones are categorized into nitinol-based, copper-based, and iron-based SMAs. Among these, NiTi has considerably attracted the attention of researchers, and it is widely applied for commercial purposes. This alloy is available in the form of a wire, bar, pipe, and plate. This alloy can hold the maximum super-elastic strain of 8% without permanent damage. Besides, Nitinol has high erosion resistance ([PERSON] [33]). Copper-based alloys are cheaper than nitinol-based ones. Moreover, they can be easily manufactured in any shape and size. Additionally, their transformation occurs in a wider temperature range. For instance, CuALBe super-elastically behaves at temperatures between \(-65\) and \(180\)\({}^{\circ}\)C. For this reason, it can be used for seismic applications in cold regions. However, this alloy can hold the maximum super-elastic strain between 2% and 4% without permanent damage ([PERSON] [33]). Also, due to martensite stabilization, this alloy shows aging at room temperature. Because iron-based SMAs, such as FeMnSi, FeNiC, and FeNiCoTi, are not expensive, they can be used instead of nitinol-based and copper-based shape memory alloys. It should be mentioned that iron-based SMAs, which have super-elastic behavior at room temperature, were found a few years ago. In 2010, an iron-based alloy was found, which could hold the maximum super-elastic strain of 15%.