Finite element analysis of pure shear in Z-shaped cementitious specimens reinforced with crimped SMA fibers

초록

This study presents a mesoscale finite element (FE) model to evaluate the pure shear behavior of Z-shaped mortar specimens reinforced with crimped NiTi shape memory alloy (SMA) fibers. Realistic fiber geometries, orientations, and random distributions were generated using an automated modeling routine, and thermal activation was simulated to capture the prestressing effect of SMA fibers. The model was validated against experimental push-off tests with fiber contents of 0%, 1.0%, and 1.25% under heated and non-heated conditions. Numerical results show that predicted peak loads deviated by less than 6.2% from experimental values, while simulated plastic strain contours closely matched digital image correlation observations. The analysis confirms that thermal activation significantly enhances shear performance by generating recovery stresses of approximately 80 MPa, which delays crack initiation and increases peak shear strength by up to 17.2%. While fiber orientation has a negligible effect prior to cracking, it becomes critical at larger displacements, with fibers oriented perpendicular to the shear plane carrying the highest tensile stresses. Among the investigated configurations, the 1.25% fiber fraction achieved the highest strength enhancement, whereas the 1.0% fraction exhibited more stable post-peak response. This validated FE framework provides a reliable tool for the analysis and design optimization of SMA-reinforced cementitious composites under shear loading. © 2026 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved. This article is available under the terms of the https://publishingsupport.iopscience.iop.org/iop-standard/v1.

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