Compression Rubber Damper Assessment Through Simulation

Rubber torsional vibration dampers are often used on mid-range engines. Usually, the geometry of a rubber torsional vibration damper is such that the rubber element in it undergoes shear. However, in the work presented, a compression rubber damper is being proposed, in which the rubber element undergoes compression rather than shear. The proposed compression rubber damper, just like the shear rubber damper, is a tuned damper. An analytical tool is being used to evaluate the stiffness of compression rubber design and thus evaluate its performance. The rubber geometry, material and plate design are selected through simulations. The analytical tool demonstrates the functionality of the compression rubber damper paper and focuses on simulation-based product development using ANSYS for FEA and an in-house tool for torsional vibration analysis.

Application of Tuned Vibration Absorber Concept to Blisk Ring Dampers: A Nonlinear Study

In this study, a novel design for ring dampers is proposed, where the concept of tuned vibration absorbers is leveraged to substantially increase damper effectiveness while minimizing potential stresses near the blade root. Tuned absorbers have been used in the past to reduce the forced response amplitudes of both mechanical and civil structures. The absorber natural frequency is tuned to the targeted frequency of the host structure where it is attached. The vibration reduction mechanism relies on energy transfer from the host structure to the absorber. The novel design technique proposed here uses a vibration absorber approach to achieve energy transfer from the blisk to the damper, which leads to larger damper motion. This enables energy dissipation due to friction, reducing vibrations even in blade-dominated modes. An academic finite element model of a blisk with a ring damper is used to demonstrate the novel tuned damper concept and design technique. The geometric mistuning of the damper due to the presence of a gap in the ring structure is also taken into account. The results demonstrate the validity of the proposed tuned damper concept, showing a substantial vibration amplitude reduction compared to the linear baseline results, in which the damper is not tuned or absent.

Application of Tuned Vibration Absorber Concept to Blisk Ring Dampers: A Nonlinear Study

In this study, a novel design for ring dampers is proposed, where the concept of tuned vibration absorbers is leveraged to substantially increase damper effectiveness while minimizing potential stresses near the blade root. Tuned absorbers have been used in the past to reduce the forced response amplitudes of both mechanical and civil structures. The absorber natural frequency is tuned to the targeted frequency of the host structure where it is attached. The vibration reduction mechanism relies on energy transfer from the host structure to the absorber. The novel design technique proposed here uses a vibration absorber approach to achieve energy transfer from the blisk to the damper, which leads to larger damper motion. This enables energy dissipation due to friction, reducing vibrations even in blade dominated modes. An academic finite element model of a blisk with a ring damper is used to demonstrate the novel tuned damper concept and design technique. The geometric mistuning of the damper due to the presence of a gap in the ring structure is also taken into account. The results demonstrate the validity of the proposed tuned damper concept, showing a substantial vibration amplitude reduction compared to the linear baseline results, in which the damper is not tuned or absent.

Application of Modular Air-Tuned Damper System in High-Rise Buildings

<p>High-rise buildings are progressively being designed and constructed in increasingly slender and complex shapes. Consequently, excessive wind-induced vibrations of these structures are a growing serviceability concern due to their flexibility. Tuned mass dampers (TMDs) are regularly incorporated into high-rise buildings for mitigating excessive wind-induced vibrations. However, traditional TMDs are only effective over a narrow domain of frequencies, require an immense mass and occupy a significant volume of interior space. A novel modular air-tuned damper system was developed which is more cost-effective and flexible in distributing its mass throughout a building to make efficient use of unused space. Importantly, the air-tuned damper system is capable of being tuned across a broad domain of frequencies to more effectively alleviate wind-induced vibrations. This paper presents a case study demonstrating the performance of a high-rise building under 1- year and 10-year wind events whilst equipped with the air-tuned damper system. Dynamic analyses were performed for evaluating the reductions of the building’s lateral accelerations considering different air-tuned damper configurations. The performance of the building under the different damper configurations is discussed.</p>