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http://www.trb.org/AnnualMeeting/AnnualMeeting.aspx

Disaster-Resilient and Self-Assessing Multifunctional Transportation Structures

Shape memory alloy (SMAs) can produce large recoverable deformations triggered by stress in a response known as superelasticity. This response has been shown to limit the damage sustained by the structure from adverse events such as earthquakes, and have been considered in a range of civil engineering applications. The most widespread SMA candidate for such applications is the nickel-titanium (NiTi) SMA, which is cost-prohibitive for large-scale applications. Instead, the research team proposes a low-cost and easily processed iron (Fe)-based SMA as an alternative. Furthermore, the iron-based SMA shows an interesting meta-magnetic shape memory response, where a change in induced magnetization of the material occurs from applied stress and can be easily detected using commercial magnetometers. This property can be harnessed to create a method to monitor the stresses and strains on structural systems with iron-based SMAs remotely and in a non-destructive fashion. The combination of these properties enable a new kind of structural health monitoring framework where the load-bearing and sensing elements are the same, and quantitative information could be collected in real-time with simple instruments. The goal of the proposed project is to create large dimension iron-based SMA rods and that are suitable for structural and transportation applications and determine the maximum part size. This study will also demonstrate bulk-Fe-SMA rods and cables that are capable of sustaining high stress and elongation. Optimal configuration of rods and sensors will be computationally determined through combined magnetic-mechanical modeling and validated through experiments. For the implementation phase of the project, the team will show that the strain in large size iron-based SMA rods and cables directly correlates with changes in its magnetic response.