Adaptive control of vibration wave propagation in cylindrical shells using SMA wall joint

A shape memory alloy (SMA) wall joint is proposed to adaptively attenuate and control the vibration wave propagation in cylindrical shells. A shape memory alloy wall joint inserted along the cylindrical shells acts as a source of mismatch of structural impedance with tunable characteristics. Thus, the SMA wall joint has the potential to solve the pass-band problem, which widely exists in the conventionally used wall joints. The performance of the SMA joint is attributed to a unique behavior of the shape memory alloy. That is, with the change of temperature, the Youngʹs modulus of the SMA can be varied up to three times of its original value as the SMA undergoes a phase transformation from martensite to austenite. With such a tunable capability an SMA wall joint can introduce proper structural impedance mismatch at different frequency, which is necessary to attenuate and control the propagation of the incident vibration wave. Because the parameter of the SMA joint can be tuned adaptively, the incident wave with different frequencies can be highly attenuated and controlled. Therefore it has the potential to solve the problem of a pass-band existing in conventional wall joints. Numerical results demonstrate that the adaptive SMA wall joint with a proper temperature is able to control the vibration from a source with wideband frequencies or time-varying frequencies, and the transmission loss is more than 20 dB. The theoretical developments of the SMA joint in this paper provide guidelines for adaptive control of vibration wave propagation and the design of such tunable structures.