Experimental investigation on the vibration tuning of a beam with shape memory alloy

The paper describes the experimental investigation on a smart beam with variable stiffness made of shape memory alloy (SMA). Quasi static experiments were performed on Ti50Ni41Cu9 SMA samples in order to obtain the mechanical characteristics including the Young's modulus and the loss factor. The test results showed, Ti50Ni41Cu9 SMA exhibited excellent damping performance in Martensite, and the storage modulus varied significantly while SMA transferred from Martensite to Austenitic. The dynamic parameters of SMA were affected by temperature and strain amplitude. Based on the mechanical characteristics of SMA tested, SMA was applied in the vibration tuning of a beam through experiments. The steady and transient response was suppressed using an effective control strategy according to the variable stiffness control theory. The steady experiments revealed that the first three order natural frequencies could be adjusted significantly by heating/cooling the SMA parts, for example the first order natural frequency varied from 60Hz to 100Hz. The temperature changing rate affected the response amplitude a lot and showed some interesting phenomenon in frequency domain. The transient experiments exhibited that the resonant response was controlled efficiently by changing the temperature of SMA, and the influence laws of the stiffness varying rate on the nonlinear dynamic characteristics was obtained.