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Fatigue Damage Characterisation of Notched Fe-SMA by Weak Magnetic Signals.
Zhi-Yu Xie1,2, Xiang Zhang1, Xu Chen3
1School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, China.
Materials (Basel, Switzerland)
|June 12, 2026
Summary
Researchers explored the magnetic properties of iron-based shape memory alloys (Fe-SMAs) to detect fatigue damage. Weak magnetic signals effectively identified and characterized local damage evolution in notched Fe-SMAs under cyclic loading.
Area of Science:
- Materials Science
- Mechanical Engineering
- Non-Destructive Testing
Background:
- Iron-based shape memory alloys (Fe-SMAs) offer potential for concrete structure strengthening.
- Non-destructive methods for identifying local fatigue damage in Fe-SMAs are limited.
- Understanding the magnetic response to damage is crucial for structural health monitoring.
Purpose of the Study:
- To investigate the weak magnetic response of notched Fe-SMA specimens.
- To correlate magnetic signals with local fatigue damage evolution under cyclic loading.
- To assess the feasibility of using magnetic signals for non-destructive damage detection.
Main Methods:
- Static tensile and constant-amplitude fatigue tests were performed on notched Fe-SMA specimens.
- Continuous monitoring of weak magnetic signals at a fixed point during loading.
- Surface magnetic-field scanning was conducted after specimen fracture.
Main Results:
- Magnetic signal evolution correlated with deformation under static loading.
- Fatigue loading showed a three-stage magnetic signal evolution linked to residual deformation.
- Magnetic hysteresis loops provided richer local damage information than deformation hysteresis loops.
- Post-fracture magnetic field scanning accurately located the fracture site.
- The normal magnetic component demonstrated high sensitivity to damage localization.
Conclusions:
- Weak magnetic signals can effectively characterize local fatigue damage evolution in notched Fe-SMAs.
- Magnetic monitoring offers a promising non-destructive method for assessing damage in Fe-SMA structures.
- The normal magnetic component is particularly sensitive for damage localization and state assessment.
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