Study on the Damping Effects of an Impact Damper Using a Elasto-Plastic Material

2006 ◽  
Author(s):  
Tomohiro Ito ◽  
Katsuhisa Fujita ◽  
Naotoshi Okaya
Keyword(s):  
Relative Velocity ◽  
Impact Force ◽  
Plastic Material ◽  
Low Cost ◽  
Restitution Coefficient ◽  
Ball Impact ◽  
Impact Damper ◽  
Force Modeling ◽  
Steel Balls ◽  
The Impact

Conventional impact dampers often utilize the steel balls because of its low cost and handling easiness. But the steel-ball impact dampers sometimes collapse or generate very large noise because of large shock at the impact. And as for the design of the impact damper, in the conventional approaches, the analytical modeling for the impact force is based on the contact theory proposed by H. Hertz, in which the restitution coefficient is assumed to be constant, i.e., the dependency on the relative velocity is not taken into consideration. However, some experimental results show that the restitution coefficient depends on the relative velocity at the impact. In this study, the elasto-plastic materials are employed as an impact damper material in order to suppress the large shock for the damper vessel and large impact noise. Therefore, the impact force modeling is modified so as that the elasto-plasticity of the material can be considered. This modeling can also consider the dependency of the restitution coefficient on the relative velocity. An impact damper which composed of a vessel and several particles made of elasto-plastic material such as lead is treated. The frequency response of the damper vessel and the damping effect of the damper are evaluated for the 2 kinds of impact force modeling by numerical simulations. Also, the effects of the particle number and the vessel configuration are evaluated. As a result, the effects of the above mentioned parameters are clarified.

Effects of Vessel Configurations on the Damping Effects of an Impact Damper Using an Elasto-Plastic Material

2007 ◽  
Author(s):  
Tomohiro Ito ◽  
Katsuhisa Fujita ◽  
Naotoshi Okaya
Keyword(s):  
Numerical Simulations ◽  
Impact Force ◽  
Collision Frequency ◽  
Plastic Material ◽  
Impact Damper ◽  
Frequency Responses ◽  
Force Modeling ◽  
Elasto Plasticity ◽  
Damping Effects ◽  
The Impact

In this study, the damping effects of an impact damper which consists of a vessel and elasto-plastic balls are evaluated. Lead is employed as an elasto-plastic material. Numerical simulations are performed based on a discrete element method. In the numerical simulations, the impact force modeling is modified so as that the elasto-plasticity of the material can be considered. And the rotation of a particle is also considered to simulate the actual particle behaviors at the collision. Frequency responses of the vessel and the damping effect of the damper are evaluated for 2 kinds of impact force models. Also, the effects of vessel dimensions, vessel configurations and the excitation directions are investigated. As a result, the effects of the above mentioned parameters are clarified.

Experimental study of passive vibration suppression using absorber with spherical ball impact damper

2016 ◽  
Vol 231 (17) ◽  
pp. 3193-3201 ◽  
Author(s):  
Riadh Chaari ◽  
Fathi Djemal ◽  
Fakher Chaari ◽  
Mohamed Slim Abbes ◽  
Mohamed Haddar
Keyword(s):  
Vibration Suppression ◽  
Industrial Applications ◽  
Design Parameters ◽  
Particle Impact ◽  
Ball Impact ◽  
Impact Damper ◽  
Ball Size ◽  
Wide Range ◽  
The Impact ◽  
Impact Damping

Impact dampers are efficient in many industrial applications with a wide range of frequencies. An experimental analysis of the impact damping of spherical balls is investigated to simplify the particle impact damping design and improve the vibration suppression. The objective of the study is to analyze some of the design parameters of impact damper using spherical balls. The experimental investigation consists to test the effect of the ball size for each mass level, the number of balls for each size level and different exciting force levels on vibrations of the main structure. The parametric study provided useful information to understand and optimize Particle Impact Damping design.

Interval of restitution coefficient for chattering in impact damper

2021 ◽  
pp. 146134842110518
Author(s):  
Zongqi Li ◽  
Yanchen Du
Keyword(s):  
Frequency Ratio ◽  
Control Parameter ◽  
Coefficient Of Restitution ◽  
Restitution Coefficient ◽  
Mass Ratio ◽  
Collision System ◽  
Impact Damper ◽  
Periodic Movement ◽  
Movement Characteristics ◽  
The Impact

Based on the impact damper, a dynamic model of a non-fixed constrained collision system was established. The coefficient of restitution is used as the main control parameter to analyze the system’s periodic movement and its bifurcation region. The chattering movement characteristics of the system were revealed. The interval of restitution coefficient for the chattering of collision system under various mass ratio and frequency ratio was obtained. The results show that the chattering phenomenon occurs in the collision system when the coefficient of restitution is greater than 0.5; as the mass ratio decreases, the interval of restitution coefficient for chattering continues to expand; as the frequency increases, the interval of restitution coefficient for chattering narrows.

scholarly journals Modeling and analysis of impact based on numerical and experimental approaches

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881306
Author(s):  
Xupeng Wang ◽  
Yan Zhang ◽  
Zhu Gao ◽  
Xiaomin Ji ◽  
Lin Li
Keyword(s):  
Mechanical System ◽  
Contact Force ◽  
Impact Force ◽  
Numerical Results ◽  
Experimental Results ◽  
Force Model ◽  
Restitution Coefficient ◽  
Contact Force Model ◽  
Improved Model ◽  
The Impact

Impact is a universal phenomenon and has serious influences on the dynamic characteristics of mechanical system, so it is critical to accurately describe the effects of impact. In this work, a numerical and comprehensive method is presented to calculate the impact force in clearance joint during impact process, which has higher effectiveness and accuracy than the most popular used L-N model. Different from traditional contact models, where the coefficient of restitution is assumed to be a constant value nearly to 1 during impact process, the improved model in this work sets up the model of restitution coefficient related to two important parameters for impact phenomenon, which are initial impact velocity and the yield strength of the materials in clearance joints. A great number of numerical and experimental results are introduced and compared to validate the improved contact force model; it needs to be highlighted that the numerical results are based on the improved model and the most popular impact force model presented by Lankarani and Nikravesh, and the experimental results are based on two typical pendulum experimental test rigs. It can be concluded that (1) when compared to the experimental results, the numerical results based on the improved model are in better agreement than those based on Lankarani and Nikravesh impact force model; (2) the numerical results based on the improved model are in reasonable agreement with the experimental results, and the relative errors of impact force and restitution coefficient are all no more than 10% between numerical and experimental results; and (3) the improved contact force model is effective and can exactly describe the impact effects between two bodies in mechanical system.

Comparative Study of Crack Length and Damage Volumes on Ceramic Coated Glass by Particle Impact

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1335-1341 ◽  
Author(s):  
Chang Min Suh ◽  
Moon Hwan Lee ◽  
Sung Ho Kim ◽  
Dong Gyun Kim ◽  
Young Guen Choi ◽  
...  
Keyword(s):  
Impact Damage ◽  
Plasma Coating ◽  
Steel Ball ◽  
Coating Materials ◽  
Ball Impact ◽  
Damage Behavior ◽  
Coated Glass ◽  
Coating Method ◽  
Steel Balls ◽  
The Impact

A ceramic plasma-coating method that reduces impact damage from the impact by round particles to a ceramic material is suggested. A steel-ball impact test was performed to investigate and compare the damage behavior of uncoated and ceramic-coated glass relative to the impact velocity and impact energy of the steel balls. Damaged volume measured and compared, for different steel-ball diameters and types of coating materials, Al 2 O 3- TiO 2, Al 2 O 3, and Cr 2 O 3. In addition, experimental equations were derived from the results, to define the experimental properties of the damage behavior exhibited by the ceramic-coated and uncoated glass.

The Behaviour of the Impact Damper

1965 ◽  
Vol 180 (1) ◽  
pp. 895-906 ◽  
Author(s):  
M. M. Sadek
Keyword(s):  
Differential Equation ◽  
Impact Force ◽  
Equation Of Motion ◽  
Dynamic Equations ◽  
Vibrational Amplitude ◽  
Time Curve ◽  
Impact Damper ◽  
Rectangular Shape ◽  
Force Time ◽  
The Impact

In this investigation a theory is developed relating to the behaviour of the impact damper. The analysis is based on the assumptions that (1) two un-equispaced impacts per cycle occur in the steady state, and (2) the impact force-time curve is of rectangular shape and of infinitesimal duration. Fourier series are used to represent the impact cycle and the differential equation of motion is derived. This is solved using the dynamic equations of impact to determine the boundary conditions. Three equations are developed to determine the variation of impulse, phase angle and vibrational amplitude with the change of the damper parameters. Resonance curves are obtained and the theory is examined experimentally. The regions of validity of the above assumptions are studied both theoretically and experimentally. Non-linearity in the behaviour of this damper is very clear, especially in the range of its optimum behaviour. Two design curves are developed which can be used to determine the damper parameters necessary for a certain amplitude reduction.

Impact Force of a Rigid-Plastic Missile

1984 ◽  
Vol 51 (1) ◽  
pp. 102-106 ◽  
Author(s):  
M. P. White
Keyword(s):  
Critical Velocity ◽  
Contact Force ◽  
Impact Force ◽  
Plastic Material ◽  
The Other ◽  
Rigid Plastic ◽  
Impact Process ◽  
Rigid Plastic Material ◽  
Time Variations ◽  
The Impact

A cylindrical missile, assumed to be of a rigid-plastic material strikes a nonyielding target normally and end-on. Above a certain (critical) velocity the nose of the missile disintegrates or spatters, and below that velocity the nose flattens to a mushroom form. The contact force decreases with decreasing velocity during impact but experiences a jump as the critical velocity is passed during slowdown. This paper gives a method of calculating the critical velocity and the contact force as function of time, as well as the time variations of the other parameters of the impact process.

Effects of Impact Angle on Cone Crack Formation in Impact-Loaded Soda-Lime Glass

2004 ◽  
Vol 261-263 ◽  
pp. 319-324 ◽  
Author(s):  
Moon Saeng Kim ◽  
Hyung Seop Shin ◽  
Hyeon Chul Lee ◽  
Ho Jong Kim
Keyword(s):  
Crack Formation ◽  
Soda Lime ◽  
Impact Angle ◽  
Soda Lime Glass ◽  
Ball Impact ◽  
Cone Crack ◽  
Cone Formation ◽  
Punching Process ◽  
Steel Balls ◽  
The Impact

In order to investigate the possibility of punching process of brittle material by ball impact, effects of impact angle on cone crack formation in impact-loaded soda-lime glass were evaluated experimentally. Evaluated were also contact area between specimen and sealing, and the optimal condition for cone crack formation in glass plates by impact with small steel balls. It has been found that lateral and radial cracks gradually developed asymmetrically. However, the perfect cone cracks were found to develop almost symmetrically. As the impact angle increased, the growth rate of cone cracks decreased. Regardless of the impact angle, the PMMA sealing was more effective for perfect cone formation than Aluminum and Polyurethane sealing. Thus, the application for industrial technology for hole (or nozzle) punching process of the brittle materials is expected to be feasible, based upon proper selection of sealing materials.

Experimental Investigation of the Impact Force That Occurs When a Roller Seats on the Sprocket During Normal Operation of a Roller Chain Drive

1992 ◽  
Author(s):  
James C. Conwell ◽  
Glen E. Johnson ◽  
S. W. Peterson
Keyword(s):  
Experimental Investigation ◽  
Effective Mass ◽  
Relative Velocity ◽  
Impact Force ◽  
Empirical Relation ◽  
Normal Operation ◽  
Practical Concern ◽  
Wide Range ◽  
Noise Vibration ◽  
The Impact

Abstract As a roller “seats” onto a sprocket, an impact force occurs between these two elements due to the relative velocity between the roller and the sprocket tooth recess. This impact force is of interest because it can be related to chain noise, vibration, wear, and other phenomena of practical concern in the performance of chain drives. The magnitude of the impact force is equal to the product of the effective mass, the relative velocity, and the reciprocal of the time associated with the impact event. Unfortunately, it is difficult to estimate the effective mass, relative velocity, and appropriate impact time in order to estimate the impact force. In this paper we present the results from a recent experimental investigation of this impact force. The experimental procedure is described, and data are presented for a wide range of initial tensions, transmitted loads, and chain speeds. As might be expected, impact force increases rapidly with increases in chain speed. An empirical relation for impact force as a function of chain speed and chain tension is presented and general observations about the data are presented and discussed.

Sign in / Sign up

Export Citation Format

Share Document