Control Performance and Preliminary Application Investigation of Novel Rotational Impact Dampers
ObjectiveA new type of control device, the Rotational Impact Damper (RID), is proposed. This device is developed based on two types of mass dampers and consists of multiple rotating bodies that rotate about a fixed axis within the same plane. Adjacent rotating bodies rotate and collide when excited,...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Editorial Department of Journal of Sichuan University (Engineering Science Edition)
2025-07-01
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| Series: | 工程科学与技术 |
| Subjects: | |
| Online Access: | http://jsuese.scu.edu.cn/thesisDetails#10.12454/j.jsuese.202301072 |
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| Summary: | ObjectiveA new type of control device, the Rotational Impact Damper (RID), is proposed. This device is developed based on two types of mass dampers and consists of multiple rotating bodies that rotate about a fixed axis within the same plane. Adjacent rotating bodies rotate and collide when excited, dissipating energy without inducing excessive acceleration in the structure.MethodsFirstly, the working principle of RID was introduced. The working principle of RID was divided into two aspects, namely, non-collision and collision states. For the non-collision state, the equations of motion (EOMs), including the EOM for the main structure and the EOMs for each rotating body in RID, were established. For the collision state, a collision model was established. In particular, when adjacent rotating bodies collided in RID, their motion followed the law of conservation of momentum and accounted for the coefficient of restitution. Secondly, dynamic tests were conducted to compare the experimental and numerical responses of three rotating bodies. As the collision of RID under dynamic loading was random, the numerical responses were not the same as the experimental responses. However, remarkable similarities were observed in their response tendencies and statistics. Therefore, it was considered that the numerical results accurately reflected the physical reality, predicting the rotation angle and rotational angular velocity with relatively good consistency. Following the verification of the effectiveness of the numerical model and the correctness of the theoretical model, the numerical model of the RID was used for subsequent numerical simulation research. Thirdly, for main structures with similar dynamic properties in the two horizontal directions, a simplification was conducted to model the structure as a unidirectional structure. Numerical optimization was conducted to determine the control parameters of the RID under simple excitation. The numerical optimization method was divided into six steps. Step 1: RID mass, rotational collision angle, and recovery coefficient were set. Step 2: All possible initial angles for each rotating body were determined based on the collision angle. Step 3: The inspection range for the radius and damping coefficient of the rotating body was set. Step 4: A pair of rotating body radius and damping coefficients were selected for the numerical simulation, and the structural response under all possible initial angle conditions was obtained. Step 5: The root mean square of the structural response under various initial angle conditions was calculated, and the average value was taken as the vibration reduction index. Step 6: all radii and damping coefficients of the rotating body were traversed, repeating the fourth and fifth steps, with the optimization goal of achieving the minimum vibration reduction index. The radius and damping coefficient of the rotating body corresponding to this minimum value were the optimal control parameters for this RID. Finally, to explore the potential application scenarios of RID, two main structures were selected and analyzed through numerical simulation. The first structure was a flexible structure with a period greater than 1 second, such as a wind turbine structure. The finite element model of the wind turbine structure was established in SAP2000 finite element software, and the finite element model was simplified as a lumped-mass model with 10 degrees of freedom for MATLAB numerical simulation. Three representative earthquake records were selected to analyze the control performance of RID under seismic excitations, and the peak ground accelerations were scaled to match the structural response under the load used in the optimization, corresponding to strong seismic excitations. In addition, the wind turbine structure maintained strong vibration even after the earthquake, so an additional 60 seconds were added to the original earthquake records. The other study investigated the RID vibration reduction performance when applied to a rigid structure (such as mechanical equipment) with a period of less than 1 second under harmonic resonance excitation. Considering the changes in the structural dynamic characteristics of mechanical equipment due to differences in load, clamping tightness, and output, this study also examined three additional structures with natural vibration periods reduced to 67%, 50%, and 40% of the original structure period, in addition to the original structure. A tuned mass damper (TMD) with a mass ratio of 5% was also considered in the resonance response analysis to study the control effect of RID on resonance response under harmonic base displacement excitation and to explain the characteristics of RID vibration reduction control. TMD was numerically optimized using the same primary structure, installation position, load, and response indicators as RID.Results and DiscussionsThe analysis results indicate that in the seismic control of flexible structures, when the seismic response closely aligns with the optimized response amplitude, the seismic reduction effect of the RID is substantial. However, as a passive control device, the RID requires a specific response time, and its seismic performance is influenced by the time-domain characteristics of earthquakes. Furthermore, a considerable reduction in seismic effects leads to decreased rotational motion and fewer collisions of the RID, which results in a significant degradation in control effectiveness and highlights the RID’s strong dependence on energy input. Given the stochastic nature of seismic excitations, the seismic control performance of the RID still presents opportunities for improvement. In the context of resonance response control for rigid structures, when the structural dynamic characteristics remain unchanged, the vibration reduction performance of the RID is not as strong as that of the TMD. However, as the structural dynamic characteristics vary, the effectiveness of the TMD gradually diminishes, whereas the vibration reduction capability of the RID remains largely unaffected by such changes, demonstrating a more stable vibration reduction performance. Additionally, the spatial requirements of the RID do not increase with growing loads, unlike those of the TMD, for which the stroke increases proportionally with the load increment. Under significant excitation, the primary structure controlled by the RID exhibits strongly modulated responses that facilitate targeted energy transfer under impulsive loads, emphasizing the necessity for further investigation in future RID research efforts.ConclusionsIn summary, the RID shows significant seismic reduction effects when seismic responses approximate optimized amplitudes, especially in flexible structures. The RID’s performance is influenced by earthquake time-domain characteristics and depends heavily on energy input due to reduced rotational motion and collisions under diminished seismic effects. While it is less effective than TMDs under unchanged structural dynamics in rigid structures, the RID maintains stable vibration reduction as structural characteristics vary and does not require increased spatial capacity with load increments. The strongly modulated responses under high excitations enhance targeted energy transfer, illustrating the RID’s potential and the need for continued research. These findings underline the RID’s theoretical and practical value in seismic control applications. |
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| ISSN: | 2096-3246 |