scholarly journals Vibration Damping Effect of the Impact Damper for a Piecewise Linear Mass Spring System

1973 ◽  
Vol 39 (322) ◽  
pp. 1833-1845
Author(s):  
Gen YAMADA
Keyword(s):  
Piecewise Linear ◽  
Vibration Damping ◽  
Linear Mass ◽  
Impact Damper ◽  
Damping Effect ◽  
Spring System ◽  
Mass Spring ◽  
The Impact

The Onset of Chaos in a Two-Degree-of-Freedom Impacting System

1989 ◽  
Vol 56 (1) ◽  
pp. 168-174 ◽  
Author(s):  
Jinsiang Shaw ◽  
Steven W. Shaw
Keyword(s):  
Piecewise Linear ◽  
Global Bifurcation ◽  
Degree Of Freedom ◽  
Chaotic Motions ◽  
Impact Damper ◽  
Onset Of Chaos ◽  
Spring System ◽  
Stability And Bifurcations ◽  
Mass Spring ◽  
Two Degree Of Freedom

The dynamic response of a two-degree-of-freedom impacting system is considered. The system consists of an inverted pendulum with motion limiting stops attached to a sinusoidally excited mass-spring system. Two types of periodic response for this system are analyzed in detail; existence, stability, and bifurcations of these motions can be explicitly computed using a piecewise linear model. The appearance and loss of stability of very long period subharmonics is shown to coincide with a global bifurcation in which chaotic motions, in the form of Smale horseshoes, arise. Application of this device as an impact damper is also briefly discussed.

Experimental Study of the Influence of Impact Mass on Damping Performance of Impact Dampers

2012 ◽  
Vol 246-247 ◽  
pp. 169-172
Author(s):  
Yan Zhu ◽  
Shi Shun Zhu ◽  
Wu Quan Liu ◽  
Shun Tang Hu
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Experimental Method ◽  
Total Mass ◽  
Resonance Region ◽  
Impact Damper ◽  
Damping Effect ◽  
Main System ◽  
The Impact ◽  
Impact Mass

We present a simulating experimental method used for studying the influence of impact mass on damping performance of impact dampers. The free mass in the impact damper had equal total mass but different size individual. We tested the damping effect of the damper under the same external force separately. The main results obtained in the experiments indicated that the impact damper had a good damping effect in the resonance region of the main system. The mass value of the free mass participating in vibro-impact was variable. In addition, the damping of the main system was related to the size of the free mass. In the conditions of equal total mass and same material, the size of the free mass was smaller, the effect of the vibration control was better.

scholarly journals Neural Network Control of a Robot Interacting With an Uncertain Hunt-Crossley Viscoelastic Environment

2008 ◽  
Author(s):  
S. Bhasin ◽  
K. Dupree ◽  
P. M. Patre ◽  
W. E. Dixon
Keyword(s):  
Neural Network ◽  
Network Control ◽  
Contact Dynamics ◽  
Neural Network Control ◽  
Contact Conditions ◽  
Real Behavior ◽  
Spring System ◽  
Mass Spring ◽  
The Impact ◽  
Viscoelastic Contact

The objective in this paper is to control a robot as it transitions from a non-contact to a contact state with an unactuated viscoelastic mass-spring system such that the mass-spring is regulated to a desired final position. A nonlinear Hunt-Crossley model, which is physically consistent with the real behavior of the system at contact, is used to represent the viscoelastic contact dynamics. A Neural Network feedforward term is used in the controller to estimate the environment uncertainties, which are not linear-in-parameters. The NN Lyapunov based controller is shown to guarantee uniformly ultimately bounded regulation of the system despite parametric and nonparametric uncertainties in the robot and the viscoelastic environment respectively. The proposed controller only depends on the position and velocity terms, and hence, obviates the need for measuring the impact force and acceleration. Further, the controller is continuous, and can be used for both non-contact and contact conditions.

scholarly journals DETERMINATION OF THE WAVE ATTACK ANTICIPATED UPON A STRUCTURE FROM LABORATORY AND FIELD OBSERVATIONS

2011 ◽  
Vol 1 (7) ◽  
pp. 37
Author(s):  
W.A. Venis
Keyword(s):  
Comparative Study ◽  
Model Tests ◽  
Water Levels ◽  
Field Observations ◽  
Wave Impact ◽  
Spring System ◽  
Mass Spring ◽  
The Comparative Study ◽  
The Impact

Model tests have been carried out to obtain an insight into the magnitude of the wave-pressures in various situations. These tests showed, that sharp high pressure peaks occur in addition to the pressures caused by the reflecting of the waves, which pressures are quasi-static. As the structure can be compared with a multiple mass-spring system these pressure-peaks may cause the whole construction to vibrate. Wave-attack therefore can be expressed in terms of impact. Moreover, calculations revealed that the impact pressures were critical factors in determining the strength of the structure. So many model tests were carried out to determine the design and location of the sluices. These tests involved numerous water-levels discharges and waves. Regarding the pressure-peaks a comparative study was made in the model, which led to the structure being designed in such a way that the occurrence of critical impacts was reduced to an acceptable minimum. As it was impossible to avoid the occurrence of impact pressures entirely it remained necessary to determine a basic load for the structure that takes care of the impact pressures. As it has not yet appeared possible physically to determine a theoretical maximum for the impact pressures, it has to be borne in mind that there is a probability that each pressure measured will be exceeded. So this paper describes, how the cumulative frequency curve of the impacts for the case mentioned in 1.1 sub a, which served as a basis for determining the basic load was arrived at by a certain combination of laboratory and field observations. The data used for this purpose were a. Results of wave-impact measurements on a model of the sluices. This model, built in accordance with the results of the comparative study, was situated in the wind-flume of the "de Voorst" hydraulic laboratory. b. Wave height measurements in the Haringvliet during 1957 and 1958. c. Wind-speed measurements on board the lightship Qoeree, likewise during 1957 and 1958. d. Tidal registrations at Hellevoetsluis from 1920 to 1960. e. Wind-force data from the Hook of Holland, likewise from 1920 to 1960.

Numerical Integration Method to Determine Periodic Solutions of Nonlinear Systems

2005 ◽  
Author(s):  
Takao Torii ◽  
Nobuyoshi Morita ◽  
Kimihiko Yasuda
Keyword(s):  
Nonlinear Systems ◽  
Numerical Integration ◽  
Integration Method ◽  
Piecewise Linear ◽  
Special Treatment ◽  
Numerical Integration Method ◽  
Impact Damper ◽  
Coulomb’S Friction ◽  
Linear Spring ◽  
Spring System

A new method to obtain periodic solution of nonlinear systems is proposed by combining secant method with numerical integration. This method can be applied to nonlinear systems with discontinuous characteristics without special treatment. To check the validity of the proposed method, we applied this method to nonlinear systems with discontinuous characteristics, such as piecewise linear spring system, system with Coulomb’s friction and impact damper system. Comparing the results by the proposed method with the results by simple numerical integration or experimental results, the validity of the proposed method is confirmed.

Experimental Study on Impact Damper with Activated Carbon Fine Particles

2014 ◽  
Vol 852 ◽  
pp. 485-489
Author(s):  
Yan Chen Du ◽  
Xiao Le Wu ◽  
Zhe Liu ◽  
Yan Yu Zhou
Keyword(s):  
Experimental Study ◽  
Activated Carbon ◽  
Experimental Method ◽  
Fine Particles ◽  
Resonance Region ◽  
Impact Damper ◽  
Damping Effect ◽  
Main System ◽  
The Impact ◽  
Better Than

The activated carbon fine particles, as damping agents, are filled into the impact damper. With experimental method, the performance of the fine particles impact damper to the main system is compared with the multi-unit impact damper. The results indicate that the damping effect of the impact damper with activated carbon fine particles is not better than that of the multi-unit impact damper, but it has a much better effect to restrain the strong nonlinear of response than the multi-unit impact damper. In a certain resonance region, there is an optimum particle filled rate to the fine impact damper.

An Arrow-Shaped Honeycomb Pedestal With Negative Poisson Ratio and its Impact Resistance

2019 ◽  
Author(s):  
Haoran Wu ◽  
Xiaobin Lin ◽  
Jie Zhang
Keyword(s):  
Fracture Toughness ◽  
Shear Modulus ◽  
Dynamic Load ◽  
Static Load ◽  
Poisson Ratio ◽  
Impact Resistance ◽  
Honeycomb Structure ◽  
Vibration Damping ◽  
Damping Effect ◽  
The Impact

Abstract The ship’s pedestal is the connection structure between the ship’s equipment and the hull, and is also the basis for the installation of the equipment. The pedestal bears both the static load generated by the weight of the equipment and the dynamic load generated during the operation of the equipment, and at the same time transmits the external load received by the hull to the equipment, and the load it bears is very complicated. If there is a problem with the pedestal in an impact environment, the accuracy of the system equipment will be affected, the system equipment will not work properly. Negative Poisson’s ration structures have a unique set of properties because of their tensile expansion, such as increased shear modulus, enhanced fracture toughness, better energy absorption and co-curvature. In recent years, the negative Poisson’s ration honeycomb structure has been applied to the pedestal of marine equipment, which demonstrates good vibration damping effect. However, the pedestal has two functions: vibration damping and impact resistance, there is not much research on the impact resistance of the pedestal. In this paper, an “arrow-shaped” honeycomb pedestal is taken as the research object. Firstly, the analytical expression of the Poisson’s ration of the honeycomb pedestal is derived theoretically and the influence of each parameter on the Poisson’s ration is analyzed. Secondly, the effect of Poisson’s ration on the impact resistance of the pedestal was analyzed by ensuring that the pedestal height was constant. It was found that with the reduction of Poisson’s ration, the impact resistance of the pedestal and the output impact environment of the pedestal panel were effectively optimized. Finally, by ensuring that the height of the pedestal is constant and the Poisson’s ration is the same, the influence of the number of honeycomb layers on the impact resistance of the pedestal is analyzed.

scholarly journals Forced Response of a Centrifugal Compressor Stage Due to the Impeller–Diffuser Interaction

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Edward J. Walton ◽  
Choon S. Tan
Keyword(s):  
Practical Implication ◽  
Forced Response ◽  
Physical Interaction ◽  
Impeller Blade ◽  
Forcing Function ◽  
Modal Coupling ◽  
Spring System ◽  
Unsteady Loading ◽  
Mass Spring ◽  
The Impact

The impact mode coupling between impeller blades and the disk backwall has on the forced response amplitude of impeller blades is assessed. The assessments focus on the forced response of two splitter blade modes to a variety of representative boundary conditions and unsteady loadings. The forcing function is the synchronous unsteady loading generated by the impeller–diffuser interaction at resonance. The results indicate that modal coupling of blade- and disk-dominant modes renders the forced response highly sensitive to small variations in airfoil and disk backwall thickness. As a complement, a reduced-order model based on the forced response of a two mass–spring system is used to elucidate the physical interaction of modal coupling. The practical implication of this finding is that a forced response issue with an impeller blade cannot be addressed adequately by stiffening the structure, such as thickening the blade or disk. Thus, appropriate measures need to be taken to avoid potential blade–disk mode couplings within the manufacturing tolerances of the part.

Biomechanical Efficiency of Wrist Guards as a Shock Isolator

2005 ◽  
Vol 128 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Il-Kyu Hwang ◽  
Kyu-Jung Kim ◽  
Kenton R. Kaufman ◽  
William P. Cooney ◽  
Kai-Nan An
Keyword(s):  
Energy Absorption ◽  
Impact Force ◽  
Damping Ratio ◽  
Linear Mass ◽  
Human Subject Testing ◽  
Wrist Guard ◽  
The Common ◽  
Mass Spring ◽  
The Impact

Despite the use of wrist guards during skate- and snowboard activities, fractures still occur at the wrist or at further proximal locations of the forearm. The main objectives of this study were to conduct a human subject testing under simulated falling conditions for measurement of the impact force on the hand, to model wrist guards as a shock isolator, to construct a linear mass-spring-damper model for quantification of the impact force attenuation (Q-ratio) and energy absorption (S-ratio), and to determine whether wrist guards play a role of an efficient shock isolator. While the falling direction (forward and backward) significantly influenced the impact responses, use of wrist guards provided minimal improvements in the Q- and S-ratios. It was suggested based on the results under the submaximal loading conditions that protective functions of the common wrist guard design could be enhanced with substantial increase in the damping ratio so as to maximize the energy absorption. This would bring forth minor deterioration in the impact force attenuation but significant increase in the energy absorption by 19%, which would help better protection against fall-related injuries of the upper extremity.

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