Investigation of flexural behavior of crimped SMA fiber-reinforced mortar beams through experimental study and mesoscale finite element modeling

This study examined the influence of the volume fraction, distribution, and orientation of crimped shape memory alloy (SMA) fibers on the flexural behavior of mortar beams through experimental tests and mesoscale finite element model (M-FEM). In the experimental testing, five groups of beams were cast, including one group with no fibers and two groups, each having a fiber volume fraction of 1.0% and 1.5%. One group of beams with a fiber volume fraction of 1.0% and 1.5% were heated to induce the shape memory effect (SME). The beams were tested by a three-point bending test to estimate their flexural capacity. In the FE analysis, the three-dimensional M-FEM of beams with different fiber volume fractions (from 0.5% to 2.0%) was developed and implemented using Python scripting and computed with the ABAQUS environment. The FE analysis results matched well with experimental data. The maximum discrepancies are 6.5% in ultimate load and 4.5% in the corresponding displacement. Furthermore, increasing SMA fiber volume fractions up to 1.5% enhanced flexural strength in SMA fiber-reinforced mortar beams, while exceeding this fraction led to negative effects due to debonding and slippage from steel reinforcement, resulting in reduced load capacity. The heated beams to induced prestressing exhibited superior performance with an ultimate load increase of over 15.0% compared to nonheated beams. Finally, this study recommends using M-FEM to investigate the SMA fiber's reinforced structures.