scholarly journals An experimental model for the analysis of energy dissipation in particle dampers

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Niklas Meyer ◽  
Robert Seifried
Keyword(s):  
Energy Dissipation ◽  
Experimental Model ◽  
Particle Dampers

scholarly journals Damping prediction of particle dampers for structures under forced vibration using effective fields

2021 ◽  
Vol 23 (3) ◽  
Author(s):  
Niklas Meyer ◽  
Robert Seifried
Keyword(s):  
Energy Dissipation ◽  
Knowledge Exchange ◽  
Underlying Structure ◽  
Reduction Techniques ◽  
Linear Behavior ◽  
Damping Behavior ◽  
Effective Particle ◽  
Coupling Procedure ◽  
Particle Damping ◽  
Particle Dampers

AbstractParticle damping is a promising damping technique for a variety of technical applications. However, their non-linear behavior and multitude of influence parameters, hinder currently its wide practical use. So far, most researchers focus either on determining the energy dissipation inside the damper or on the overall damping behavior when coupled to a structure. Indeed, currently almost no knowledge exchange between both approaches occurs. Here, a bridge is build to combine both techniques for systems under forced vibrations by coupling the energy dissipation field and effective particle mass field of a particle damper with a reduced model of a vibrating structure. Thus, the overall damping of the structure is estimated very quickly. This combination of both techniques is essential for an overall efficient dimensioning process and also provides a deeper understanding of the dynamical processes. The accuracy of the proposed coupling method is demonstrated via a simple application example. Hereby, the energy dissipation and effective mass of the particle damper are analyzed for a large excitation range first using a shaker setup. The particle damper exhibits multiple areas of different efficiency. The underlying structure is modeled using FEM and modal reduction techniques. By coupling both parts it is shown that multiple eigenmodes of the structure are highly damped using the particle damper. The damping prediction using the developed coupling procedure is validated via experiments of the overall structure with particle damper.

scholarly journals Study on the Damping Effect of Particle Dampers considering Different Surface Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiaowei Li ◽  
Yue Yang ◽  
Weixing Shi
Keyword(s):  
Energy Dissipation ◽  
Surface Property ◽  
Material Selection ◽  
Great Influence ◽  
Contact Theory ◽  
Theoretic Model ◽  
The Finite Element Method ◽  
Particle Damping ◽  
Vibration Experiment ◽  
Particle Dampers

Particle dampers are nonlinear vibration control devices. The surface property has a great influence on the performance of the particle damper, but it is difficult to be considered and analyzed. This paper firstly gives a view of how to establish a theoretic model of the particle damper. The dynamic equation and energy dissipation coefficient of collision are revised from the Hertz contact theory in the proposed theoretic model, considering the friction of particles. Then, a contrastive collision model relying on the finite element method is established to verify the reasonability of the theoretic model. The effects of different factors which will have an influence on the performance of the particle damper are discussed, and several conclusions on how to optimize the particle damper are proposed. Except for the aforementioned dynamic analysis, this paper also presents a particle damping index to evaluate the capability of energy dissipation of different materials, in order to facilitate the material selection in the practical design. Finally, an experiment is developed to verify the character of the collision and energy dissipation. The feasibility of the proposed method to estimate the surface property of different particles is validated by the free vibration experiment.

scholarly journals Energy dissipation prediction of particle dampers

2009 ◽  
Vol 319 (1-2) ◽  
pp. 91-118 ◽  
Author(s):  
C.X. Wong ◽  
M.C. Daniel ◽  
J.A. Rongong
Keyword(s):  
Energy Dissipation ◽  
Particle Dampers

Experimental model for predicting the semi-rigid connections’ behaviour with angles and stiffeners

2016 ◽  
Vol 20 (6) ◽  
pp. 884-895 ◽  
Author(s):  
Mahyar Maali ◽  
Mahmut Kılıç ◽  
Merve Sağıroğlu ◽  
Abdulkadir Cüneyt Aydın
Keyword(s):  
Energy Dissipation ◽  
Experimental Model ◽  
Failure Modes ◽  
Bending Moment ◽  
Experimental Results ◽  
Rotation Curves ◽  
Rotation Capacity ◽  
Seat Angle ◽  
Eurocode 3 ◽  
Global Moment

This article presents the experimental results of nine specimens of steel bolted beam-to-column connections with top-and-seat angle and stiffener. All of the connections have the angles and beams reinforced with stiffeners in the extended parts. The results are analysed on the basis of the global moment–rotation curves. The main parameters observed are the failure modes, the evolution of the resistance, the stiffness, the rotation capacity, the ductility of a joint and the energy dissipation. The aim was to provide necessary data to improve the Eurocode 3. While the stiffness decreased with the increased thickness of beam stiffeners of 5–10 mm, the maximum bending moment (Mj.max) increased with the increased length of top-and-seat angle.

scholarly journals Toward a design methodology for particle dampers by analyzing their energy dissipation

2020 ◽  
Author(s):  
Niklas Meyer ◽  
Robert Seifried
Keyword(s):  
Energy Dissipation ◽  
Loss Factor ◽  
Design Methodology ◽  
Design Rules ◽  
Damping Behavior ◽  
Motion Modes ◽  
Particle Dampers ◽  
Discrete Element Simulations ◽  
Excitation Conditions ◽  
Insight Into

Abstract Particle dampers show a huge potential to reduce undesired vibrations in technical applications even under harsh environmental conditions. However, their energy dissipation depends on many effects on the micro- and macroscopic scale, which are not fully understood yet. This paper aims toward the development of design rules for particle dampers by looking at both scales. This shall shorten the design process for future applications. The energy dissipation and loss factor of different configurations are analyzed via the complex power for a large excitation range. Comparisons to discrete element simulations show a good qualitative agreement. These simulations give an insight into the process in the damper. For monodisperse systems, a direct correlation of the loss factor to the motion modes of the rheology behavior is shown. For well-known excitation conditions, simple design rules are derived. First investigations into polydisperse settings are made, showing a potential for a more robust damping behavior.

Research on the energy dissipation mechanism of nonobstructive particle dampers based on the dense granular flow theory

2016 ◽  
Vol 24 (4) ◽  
pp. 682-693
Author(s):  
Jianglong Fang ◽  
Xiaopeng Wang ◽  
Tianning Chen ◽  
Kai Zhang
Keyword(s):  
Energy Dissipation ◽  
Granular Flow ◽  
Vibrational Excitation ◽  
Side Wall ◽  
Flow Theory ◽  
Experimental Result ◽  
Energy Dissipation Mechanism ◽  
Dissipation Mechanism ◽  
Dense Granular Flow ◽  
Particle Dampers

To study the energy dissipation mechanism of nonobstructive particle dampers (NOPDs) and provide guidance to the application of NOPDs, the dense granular flow theory was introduced to establish a quantitative energy dissipation model for NOPDs. The convection movement of the particles under vibrational excitations was studied using the discrete element method, and the Prandtl mixing length theory was adopted to modify the constitution law of dense granular flows. The pressure of the granular flow was obtained by equivalenting the vibrational excitation to a body force acted on particles. Theoretical results showed that the energy dissipation rate of the NOPD was increased with the vibration intensity and decreased with the granular diameter. It also indicated that particles near the side wall and the bottom of the damper dissipated more energy than those particles in other regions. The theoretical model was verified by simulation and experimental result. The results may provide a new approach to studying the energy dissipation mechanism of NOPD and give some guidance to enhancing the damping performance of NOPD in engineering practices.

Analysis and Optimal Placement of Particle Dampers Based on Discrete Element Simulation

2015 ◽  
Author(s):  
Shilong Li ◽  
Jiong Tang
Keyword(s):  
Energy Dissipation ◽  
Discrete Element ◽  
Optimal Placement ◽  
Time Simulation ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Particle Damping ◽  
Long Time ◽  
Host Structure ◽  
Particle Dampers

Particle damper is formed by granular particles enclosed in a container which is attached to or embedded in a vibrating structure. The energy dissipation mechanism of a particle damper is highly nonlinear, and derived from a combination of collision/impact and friction among particles and between particles and the enclosure. Meanwhile, the coupling between particle dampers and the host structure and among multiple dampers further increases the difficulty to analyze the particle damping performance. In this paper, a new coupling method is developed to integrate the continuous host system with multiple particle dampers to analyze the energy transfer between the host structure and the dampers. The discrete element method (DEM) is employed to describe and analyze the particle motion inside each damper, which accurately accounts for various energy dissipation mechanisms of the particle damping system. In order to enhance the computational efficiency, a Verlet table combined with LC method is also used to improve the contact detection since the long time simulation is needed to perform damping analysis under a wide range of frequencies. The damping effect under different arrangements of particle dampers on a clamped-free beam is analyzed, and the results indicate that the optimal positions of dampers not only rely on the mode shape of the system, but also are dependent upon the excitation level.

scholarly journals Higher-Order Velocity Moments, Turbulence Scales and Energy Dissipation Rate around a Boulder in a Rock-Ramp Fish Passage

2020 ◽  
Vol 12 (13) ◽  
pp. 5385
Author(s):  
Amir Golpira ◽  
Abul BM Baki ◽  
David Z. Zhu
Keyword(s):  
Energy Dissipation ◽  
Experimental Model ◽  
Swimming Performance ◽  
Vertical Mixing ◽  
Fish Passage ◽  
Energy Dissipation Rate ◽  
Higher Order ◽  
Length Scales ◽  
Dissipation Rates ◽  
Velocity Moments

This experimental study investigated the higher-order velocity moments, turbulence time and length scales, and energy dissipation rates around an intermediately submerged boulder within a wake-interference flow regime in a rock-ramp fish passage. The results show a noticeable variation in the studied parameters in the wake of the boulder, as well as near the bed and boulder crest. The higher-order velocity moments show the presence of infrequent strong ejections downstream of the boulder, which may lead to higher sediment deposition and vertical mixing. The eddy length scales and the volumetric energy dissipation in this experimental model were discussed in relation to fish behavior for both the experimental model and a prototype. Relationships were proposed to roughly estimate integral length scales and energy dissipation rates around the boulder over the flow depth. The findings of this study may improve the design of rock-ramp fish passages considering the effects of turbulence on fish swimming performance and sediment transport.

Sign in / Sign up

Export Citation Format

Share Document