Study on the working mechanism of self-resetting performance of superelastic SMA fiber-reinforced ECC beams

This study aimed to master the self-resetting performance and working mechanism of superelastic shape memory alloy fibers reinforced engineered cementitious composite (SMAF-ECC) beams. Four SMAF-ECC pre-cut beams were fabricated. The three-point bending test was used to analyze the changes in mid-span deflection and crack width under different shape memory alloy (SMA) fibers lengths and end forms. And the stress of SMA fiber was analyzed by ABAQUS. Finally, the working mechanism of SMA fiber was revealed. The results showed that SMAF-ECC specimens perform well in deformation recovery and crack closure. Among them, the maximum deflection self-recovery rate of the specimen was 83.6%. And compared to the engineered cementitious composite (ECC) specimen, the residual crack width was reduced by 76.62% to 84.01%. In addition, reducing the length and diameter of the SMA fiber increased its stress. However, the length of SMA fiber had little effect on the deflection self-recovery rate of SMAF-ECC specimens, and the maximum difference between the specimens with different SMA fiber lengths was only 1.1%. The working mechanism of SMA fiber included four stages: linear elastic, descent, platform, and deformation strengthening stage. After the SMA fiber entered the platform phase, the residual deformation of the specimen was significantly reduced. When entering the deformation strengthening stage, the SMA fiber not only improved the bearing capacity of the specimen, but also provided greater restoring force, considerably improved the specimen’s self-resetting performance. This paper offered a theoretical basis for the design of self-resetting beams.

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Opracowanie rekordu ze środków MNiSW, umowa nr POPUL/SP/0154/2024/02 w ramach programu "Społeczna odpowiedzialność nauki II" - moduł: Popularyzacja nauki (2025)