Structural Health Monitoring using Embedded Magnetic Shape Memory Alloys for Magnetic Sensing

摘要

In the field of structural health monitoring (SHM), innovative methods of non-destructive evaluation (NDE)are currently being investigated with the purpose of safer, longer lasting structures. While current SHM isdominated by acoustic emission and vibration-based methods, it is desirable to integrate NDE techniques withexisting structural reinforcement techniques which increase structural service life. Multifunctional materials thatcan detect internal structural damage while also increasing structural service life offer an inherent advantage asconstruction materials to be integrated into new and existing structures.Embedding shape memory alloy (SMA) wires in concrete components offers the potential to monitor theirstructural health via external magnetic field sensing. SMAs have been used to close internal cracks, reinforceconcrete structures, and reduce fatigue under cyclic loading, so the addition of such a multi-functional materialfor the purpose of structural evaluation is very desirable. Thus an evaluation of SMAs for magnetic sensing isrequired for both the structural and magnetic domains.A concrete beam containing iron-based magnetic SMA (MSMA) wire is subjected to a three point bend testwhere structural damage is induced, resulting in a localized phase change of the MSMA wire. Magnetic eld linespassing through the embedded MSMA domain are altered by this phase change and can thus be used to detectdamage within the structure. A good correlation is observed between the computational and experimental results,and the magnetic sensing sensitivity is explored via a robust computational model to evaluate the e ectivenessof external magnetic sensing.