In recent years, the idea of using durable materials which are capable of absorbing energy and have high ductility are highlighted in structural engineering. One example of these materials is shape memory alloys which show predefined physical properties in different c More
In recent years, the idea of using durable materials which are capable of absorbing energy and have high ductility are highlighted in structural engineering. One example of these materials is shape memory alloys which show predefined physical properties in different conditions. These materials show little residual strain under loading and unloading cycles even when passing through the yield area. In fact, they create regenerative forces in structures. In this study, the effect of shape memory alloys on energy dissipation and reducing vibration amplitude of multi-story steel frame is investigated. For the present purpose, shape memory alloy rebars are used in the middle of the diagonal elements of braces. ABAQUS software is used in the present study. To validate models, first, two-story braced frame with shape memory alloy used in the laboratory studies of Han et al (2003) is modeled and analyzed in the software. The results obtained by the two laboratory and analytical methods are in acceptable agreement. To investigate the effect of height on the seismic performance of the buildings equipped with this type of dampers, 3- and 12-story buildings were considered and reciprocating nonlinear analysis and nonlinear dynamic time history analysis using Tabas accelerogram were performed. Results show that using this type of dampers cause quick energy dissipation and a significant reduction in the vibration amplitude and base shear so that the existence of shape memory alloy in 3-story building makes the ability of the structural system in dissipating energy and the initial stiffness of the system increase 2.5 and 2 times respectively. Moreover, with an increase in height, its effectiveness in controlling the seismic response of structure is reduced between 10-15 percent.
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In this study the seismic performance of hybrid braces composed of steel and shaped- memory alloys (SMA). is investigated Six types of hybrid braces were used, constituted by SMA content of 0, 20, 40, 60, 80, and 100%. A nonlinear dynamic analysis was performed under El More
In this study the seismic performance of hybrid braces composed of steel and shaped- memory alloys (SMA). is investigated Six types of hybrid braces were used, constituted by SMA content of 0, 20, 40, 60, 80, and 100%. A nonlinear dynamic analysis was performed under El Centro earthquake records, with the maximum acceleration of 0.6g and 0.9g. Our results showed that the seismic performance, i.e., the amount of energy absorption and residual strain, of steel–SMA hybrid braces depends on the SMA content. The optimal value of SMA content was 20%, as, at this concentration, a hybrid brace can be designed with good seismic performance at a justifiable fabrication cost.
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The shape memory alloys (SMAs) is a specific property some materials have to restore their original shape. This strange behavior has caused these materials to be classified as smart materials. Due to the capabilities of this material, it has been used in all industries, More
The shape memory alloys (SMAs) is a specific property some materials have to restore their original shape. This strange behavior has caused these materials to be classified as smart materials. Due to the capabilities of this material, it has been used in all industries, and in the last decade, its use has developed tremendously. In this article, while dealing with their general properties and production method, their applications especially in structural and earthquake engineering have been reviewed and investigated. For this reason, some of the works and studies done by structural engineering researchers in the recent period (from 2014 to 2024) in the field of structural engineering and with the approach of evaluating connections equipped by shape memory alloys have been mentioned. Finally, while examining the details of a Practical study in the field of steel column connection to the foundation, which was done with and without using of shape memory alloys, the advantages of using shape memory alloys in connections are summarized in the results.
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