Experimental study on bonding properties of Fe-SMA-to-steel bonded interface

Abstract

The interfacial bonding performance between Fe-based shape memory alloys (Fe-SMA) and steel is of utmost importance for the reinforcement of steel structures using Fe-SMA. In order to better reveal the bonding performance and ensure the reliability of Fe-SMA-to-steel bonded interfaces, the single-lap-shear tests of 27 adhesive joints were conducted. The experimental results indicate that the bearing capacity increases with the bonding length until reaching the effective bonding length (Le), with SA, Sika, and LC adhesive joints possessing Le of around 90 mm, 90 mm, and 100 mm, respectively. Better bonding performance can be achieved with 1–1.5 mm thickness for the 3 types of adhesive joints, while the bearing capacity of LC adhesive joints is less affected by the adhesive thickness. The SA joints experienced interface debonding failure, the Sika joints experienced the mixed failure mode of interface debonding and cohesive failure, and the LC joints exhibited cohesive failure. For the bonded interfaces, cohesive failure is the preferred mode, evidenced by Fe-SMA plates in LC joints reaching 60% of their tensile strength at failure. Furthermore, utilizing the established constitutive model of Fe-SMA and the strain propagation from experiments, the shear stress evolution and interfacial bond-slip relationship of Fe-SMA-to-steel bonded interfaces were analyzed, demonstrating that the nonlinear behavior and high ductility of Fe-SMA significantly affect the load-bearing performance and failure evolution. This paper verifies the feasibility of reinforcing steel structures with Fe-SMA through adhesive bonding connection, providing an experimental basis for the theoretical analysis and practical application of Fe-SMA-to-steel bonded interfaces.