Experimental study on the aeroelastic behavior of a typical airfoil section with superelastic shape memory alloy springs

An experimental study on the aeroelastic behavior of a 2-degree-of-freedom typical airfoil section with superelastic shape memory alloy springs is reported. Shape memory alloy helical springs are included in the pitch degree-of-freedom of the typical section so that the effects of pseudoelastic hysteresis on the aeroelastic behavior of the system can be investigated. The experimental identification of the aeroelastic parameters is described. Wind tunnel tests are conducted for different shape memory alloy springs’ preload levels, airflow speeds, and initial conditions. It is shown that the linear unstable post-flutter behavior is transformed into stable limit cycle oscillations of acceptable amplitudes over a range of airflow speeds due to pseudoelastic hysteresis. Therefore, shape memory alloy springs can be effectively exploited to passively enhance the aeroelastic behavior of a typical section.