Arresting fatigue cracks in steel plates using prestressed bonded Fe-SMA strips: Analytical prediction and experimental validation

Bonded iron-based shape memory alloy (Fe-SMA) strengthening has shown great potential in fatigue strengthening for steel structures. However, there is a lack of a comprehensive model for analysing the fatigue behaviour of systems strengthened with prestressed bonded Fe-SMA. This study proposes the first analytical model, integrating a prestress analysis and fatigue analysis, to predict fatigue crack arrest in steel plates strengthened with prestressed bonded Fe-SMA strips. Four steel plates, each featuring a central through-thickness crack, were strengthened using bonded Fe-SMA strips, and subsequently, tested under fatigue loading after generating prestress via heating and cooling. The proposed model succeeded in predicting (i) the fatigue crack arrest at certain load levels and (ii) onset of crack propagation at increased load levels. • Fatigue crack arrest achieved via prestressed bonded Fe-SMA strengthening. • Analytical prediction of prestress and fatigue, aligning with experimental results. • Higher activation temperature leads to greater prestressing/strengthening effect. • COD and strain gauges serve as reliable indicators of crack propagation.