Experiments on active stiffness control of a thin-walled cylindrical shell with novel SMA driven screw-type actuators

Thin-walled cylindrical shells have been widely used as key components in various engineering applications. The stiffness of the thin-walled cylindrical shell is an important factor affecting its working performance. This study aims to investigate the active stiffness control of thin-walled cylindrical shells with a new SMA (shape memory alloy) driven actuator. The configuration of the actuator is designed first according to the circumferential and axial modal characteristics of the cylindrical shell. Geometric parameters of the actuator are optimized based on the statics and modal analysis of the system. SMA tubes are used as the driving sources of the actuator and their mechanical performance, including compressive mechanical property and recovery mechanical property are tested. The active stiffness control experiments are carried out on a simply supported thin-walled cylindrical shell. The control performance of the actuator is indicated by the enhancement ratio of natural frequencies of different modes. The influences of actuator number and actuation time on the control performance are also investigated. The results demonstrate that the proposed actuator can significantly improve the stiffness of the thin-walled cylindrical shell by nearly 30%.