Turbo-machine blade vibration damper Patent

Blade vibration damping pins for turbomachiner

Vibration damping system Patent

Vibration damping system operating in low vacuum environment for spacecraft mechanism

Variable stiffness polymeric damper

Shock and vibration damping device using temperature sensitive solid amorphous polymer

The effect of geometric structure on stiffness and damping factor of wood applicable to machine tool structure

Stiffness and vibration damping capability are important criteria in design of machine tool structure. In other sides, the weight of machine tool structure must be reduced to increase the handling capability. This paper presents an analysis of the effect of geometric structure on stiffness and vibration damping of wood structure. The stiffness was analysed using numerical method, so called finite element method (FEM), while the vibration damping capability was experimentally tested. Vibration testing was also performed to wood structures with sand powder filled into its rectangular hole to observe the its effect on damping factor. Simulation results show that the cross ribs structure yielded minimum mass reduction ratio compared to the three square holes as well as the single rectangular hole structures. While the vibration test results explained that the damping factor of Shorea laevis wood was higher than that Hevea braziiensis wood. The use of sand powder as vibrating mass in closed-box structure effectively increased the damping capability, for single rectangular hole structure the damping factor was increased from 0.048 to 0.07

Vibration damping of mechanical seals

Bellows seal filled with spherical powder reacts to vibration inputs by absorbing displacement energy through inertia and friction of the particle masses acting on the inside surface of the cylinders

Lightweight load support serves as vibration damper

Omnidirectional antennas and solar panels can be supported by a thin-walled tubular strut. Silicon grease is used as the vibration-damping medium and a coil spring supports static loads

Vibration Damping of Carbon Nanotube Assembly Materials

Vibration reduction is of great importance in various engineering applications, and a material that exhibits good vibration damping along with high strength and modulus has become more and more vital. Owing to the superior mechanical property of carbon nanotube (CNT), new types of vibration damping material can be developed. This paper presents recent advancements, including our progresses, in the development of high-damping macroscopic CNT assembly materials, such as forests, gels, films, and fibers. In these assemblies, structural deformation of CNTs, zipping and unzipping at CNT connection nodes, strengthening and welding of the nodes, and sliding between CNTs or CNT bundles are playing important roles in determining the viscoelasticity, and elasticity as well. Towards the damping enhancement, strategies for micro-structure and interface design are also discussed

An approach of using polymer natural fiber composite for vibration and flammability control

Recently the development of natural fiber composite instead of synthetics fiber has lead to eco-friendly product manufacturing to meet various applications in the field of automotive, construction and manufacturing. In this present research, the effects of maleic anhydride polypropylene (MAPP) on the material characterization behaviour, mechanical properties, vibration damping properties and flammability properties of kenaf fiber and coir fiber reinforced polypropylene were investigated. Different fractions of composites with 10wt%-40wt% coir fiber (CF) and kenaf fiber (KF) content were prepared by using brabender mixer at 190 °C. The 3wt% MAPP was added during the mixing. The composites were subsequently fabricated with injection molding and hydraulic hot press to prepare the test specimens. The effect of MAPP on morphology, mechanical properties, physical properties, vibration damping properties and flammability properties of CF or KF composites were then investigated by using FTIR, SEM, tensile test, density test, transmissibility test and vertical flame test, respectively. The results revealed that the 30wt% modified kenaf fiber composite (m-PP/KF) shows the highest improvement in tensile strength compared to CF composites and unmodified composite which is 30.51 MPa. These results were also confirmed by the SEM machine observations of fracture surface of composites and FTIR analysis of the chemical structure. The result of damping analysis showed modified composites with MAPP in 30wt% CF or KF composites lead to good vibration damping which are increased up to 1017.7% and 756.9% compared to neat PP. On the other hand, the 30wt% m- PP/CF and 30wt% m-PP/KF showed the highest delay in first dripping time compared to neat PP which are increased up to 800% and 1000%. As the results, the presence of MAPP helps increasing on the mechanical properties, vibration damping properties and flammability properties of both fibers. The 30wt% kenaf fiber with 3wt% MAPP gives the best result compare to others

Dynamic characteristics and processing of fillers in polyurethane elastomers for vibration damping applications

Polyurethane elastomers have the potential of being used to reduce vibrational noise in many engineering applications. The performance of the elastomer is directly related to matching the nature of the mechanical loss characteristics to the frequency and temperature dependence of the source of the vibration. Materials with a broad frequency response and good mechanical properties are desirable for situations were load bearing and isolation becomes an issue. Because automobile, and other related vehicles operate over a broad temperature range, it is desirable for the damping characteristics of the elastomer to ideally be independent of temperature and frequency. In practice, this is not possible and the creation of materials with a broad spectrum response is desirable. In this paper, the effects of various fillers on the breadth and temperature dependence of the vibration damping characteristics of a filled and crosslinked polyurethane elastomer are explored. The fillers studied are wollastonite, barium sulphate and talc. These materials have different shapes, sizes and surface chemistry and undergo different types of interaction with the matrix. The vibration damping characteristics were further varied by the use of a crosslinking agent. Data presented on the rheological characteristics indicate the strength of the filler-polyol interactions. Dielectric relaxation and dynamic mechanical thermal analysis demonstrate the way in which changes in the type of filler, concentration and amount of crosslinker lead to changes in the location and breadth of the energy dissipation process in these elastomers. The vibration damping characteristics of a selected material are presented to demonstrate the potential of these materials

Self-tuning vibration absorber and the effect of its installation position on damping characteristics

A kind of self-tuning vibration absorber is presented. The relationship between the installation position and the vibration damping effect of the self-tuning vibration absorber is established, the influence on the damping effect is discussed. Then, on the vibration test bed, the theoretical analysis results are tested and verified. The results show that, installation position of the self-tuning vibration absorber has a significant influence on its vibration damping effect. When installed near the source location, the self-tuning vibration absorber has a better vibration damping effect. It is should be avoided in the area of vibration deterioration