Study on self‐adjustable variable pendulum tuned mass damper

Summary Pendulum tuned mass damper (PTMD) is usually used to control the horizontal vibration of a tall building. However, traditional PTMD is highly sensitive to frequency deviation and difficult to adjust its frequency. In order to improve this problem of traditional PTMD and protect a tall building more effectively, a novel PTMD, called self‐adjustable variable pendulum tuned mass damper (SAVP‐TMD), is proposed in this paper. On the basis of the acceleration ratio between TMD and primary structure, the SAVP‐TMD can retune itself by varying the length of the pendulum according to the improved acceleration ratio‐based adjustment algorithm. PTMD and primary structural accelerations are obtained from two accelerometers respectively, and the acceleration ratio is calculated in a microcontroller, then, the stepper motor will adjust the pendulum under the guidance of the microcontroller under a specific harmonic excitation. The improved acceleration ratio‐based adjustment algorithm is proposed and compared to solve the nonconvergent retuning problem. The SAVP‐TMD can be regarded as a passive damper including a frequency adjustment device. A single‐degree‐of‐freedom structure model is used to verify the effectiveness of SAVP‐TMD through both experimental study and numerical simulation. In order to further verify the effect of SAVP‐TMD in the MDOF structure, a five‐storey structure coupled with an SAVP‐TMD is proposed as a case study. The results of experiment, simulation, and case study all show that SAVP‐TMD can retune itself to the primary structural dominant frequency robustly, and the retuned PTMD has a better vibration control effect than the mistuned one.