Effect of Intermolecular Forces on the Dynamic Response of a Slider

2006 ◽  
Vol 129 (1) ◽  
pp. 177-180 ◽  
Author(s):  
Saurabh K. Deoras ◽  
Frank E. Talke
Keyword(s):  
Dynamic Response ◽  
Impulse Response ◽  
Magnetic Recording ◽  
Intermolecular Forces ◽  
Degree Of Freedom ◽  
Flying Height ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Mass Damper

A single-degree-of-freedom spring-mass-damper model has been developed to simulate the dynamic response of a typical magnetic recording slider under the effect of intermolecular forces. Thornton and Bogy (2003, IEEE Trans. Magn., 39(5), pp. 2420–2422) have previously reported that the slider “snaps” to the surface of the disk, below a certain “critical” flying height, due to the intermolecular forces. We have studied impulse response of the model to show that the slider can snap even at flying heights greater than the critical flying height and that the occurrance of snapping also depends on the magnitude of the applied impulse.

The Dynamics of a Nonharmonically Excited System Having Rigid Amplitude Constraints

1992 ◽  
Vol 59 (3) ◽  
pp. 693-695 ◽  
Author(s):  
Pi-Cheng Tung
Keyword(s):  
Dynamic Response ◽  
Bifurcation Analysis ◽  
Piecewise Linear ◽  
Coefficient Of Restitution ◽  
Degree Of Freedom ◽  
Linear Oscillator ◽  
Chaotic Motions ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Excited System

We consider the dynamic response of a single-degree-of-freedom system having two-sided amplitude constraints. The model consists of a piecewise-linear oscillator subjected to nonharmonic excitation. A simple impact rule employing a coefficient of restitution is used to characterize the almost instantaneous behavior of impact at the constraints. In this paper periodic and chaotic motions are found. The amplitude and stability of the periodic responses are determined and bifurcation analysis for these motions is carried out. Chaotic motions are found to exist over ranges of forcing periods.

Effects of human-induced load models on tuned mass damper in reducing floor vibration

2019 ◽  
Vol 22 (11) ◽  
pp. 2449-2463
Author(s):  
Jun Chen ◽  
Ziping Han ◽  
Ruotian Xu
Keyword(s):  
Response Spectra ◽  
Tuned Mass Damper ◽  
Design Guidelines ◽  
Degree Of Freedom ◽  
Dynamic Responses ◽  
Single Degree Of Freedom ◽  
Load Model ◽  
Load Models ◽  
Single Degree ◽  
Mass Damper

Dozens of human-induced load models for individual walking and jumping have been proposed in the past decades by researchers and are recommended in various design guidelines. These models differ from each other in terms of function orders, coefficients, and phase angles. When designing structures subjected to human-induced loads, in many cases, a load model is subjectively selected by the design engineer. The effects of different models on prediction of structural responses and efficiency of vibration control devices such as a tuned mass damper, however, are not clear. This article investigates the influence of human-induced load models on performance of tuned mass damper in reducing floor vibrations. Extensive numerical simulations were conducted on a single-degree-of-freedom system with one tuned mass damper, whose dynamic responses to six walking and four jumping load models were calculated and compared. The results show a maximum three times difference in the acceleration responses among all load models. Acceleration response spectra of the single-degree-of-freedom system with and without a tuned mass damper were also computed and the response reduction coefficients were determined accordingly. Comparison shows that the reduction coefficient curves have nearly the same tendency for different load models and a tuned mass damper with 5% mass ratio is able to achieve 50%–75% response reduction when the structure’s natural frequency is in multiples of the walking or jumping frequency. All the results indicate that a proper load model is crucial for structural response calculation and consequently the design of tuned mass damper device.

Three-Element Vibration Absorber–Inerter for Passive Control of Single-Degree-of-Freedom Structures

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Abdollah Javidialesaadi ◽  
Nicholas E. Wierschem
Keyword(s):  
Passive Control ◽  
Translational Motion ◽  
Tuned Mass Damper ◽  
Degree Of Freedom ◽  
Superior Performance ◽  
Underlying Structure ◽  
Vibration Absorber ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Mass Damper

In this study, a novel passive vibration control device, the three-element vibration absorber–inerter (TEVAI) is proposed. Inerter-based vibration absorbers, which utilize a mass that rotates due to relative translational motion, have recently been developed to take advantage of the potential high inertial mass (inertance) of a relatively small mass in rotation. In this work, a novel configuration of an inerter-based absorber is proposed, and its effectiveness at suppressing the vibration of a single-degree-of-freedom system is investigated. The proposed device is a development of two current passive devices: the tuned-mass-damper–inerter (TMDI), which is an inerter-base tuned mass damper (TMD), and the three-element dynamic vibration absorber (TEVA). Closed-form optimization solutions for this device connected to a single-degree-of-freedom primary structure and loaded with random base excitation are developed and presented. Furthermore, the effectiveness of this novel device, in comparison to the traditional TMD, TEVA, and TMDI, is also investigated. The results of this study demonstrate that the TEVAI possesses superior performance in the reduction of the maximum and root-mean-square (RMS) response of the underlying structure in comparison to the TMD, TEVA, and TMDI.

scholarly journals Dynamic Response of RC Cantilever Beam by Equivalent Single Degree of Freedom Method on Elastic Analysis – A Review on Transformation Factors and Dynamic Magnification Factors

2018 ◽  
Vol 159 ◽  
pp. 01005
Author(s):  
Sri Tudjono ◽  
Patria Kusumaningrum
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Cantilever Beam ◽  
Mode Shape ◽  
Degree Of Freedom ◽  
Elastic Analysis ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Magnification Factors ◽  
Method Analysis

The response of multi-degree-of-freedom (MDOF) structure can be correlated to the response of an equivalent single-degree-of-freedom (SDOF) system, implying that the response is controlled by a single, unchanged mode shape. This equivalent SDOF method is eminent as an approximate method of dynamic analysis. In this study, equivalent SDOF method analysis is carried out on RC cantilever beam subjected to dynamic blast loading to review the transformation factors (TFs) provided by TM5-1300 code.

scholarly journals Dynamic Response of Breasting Dolphin Moored with 40,000 DWT Ship due to Parallel Passing Ship Phenomenon

2018 ◽  
Vol 147 ◽  
pp. 05003
Author(s):  
Heri Setiawan ◽  
Muslim Muin
Keyword(s):  
Differential Equation ◽  
Ordinary Differential Equation ◽  
Dynamic Response ◽  
Computer Program ◽  
Lateral Force ◽  
Degree Of Freedom ◽  
Hydrodynamic Interactions ◽  
Single Degree Of Freedom ◽  
Sdof System ◽  
Single Degree

When a ship is moving through another ship moored nearby, hydrodynamic interactions between these ships result in movements of the moored vessel. The movement may occur as surge, sway, and/or yaw. When a ship is passing a moored vessel parallelly, this effect will give a dominant lateral force on the moored ship and response from this phenomenon will appear in a certain time. Only dynamic response due to sway force is considered in this study, the sway force shall be absorb by the breasting dolphin. 40,000 DWT shall be moored to the breasting dolphin. Three passing ships size are considered, the breasting dolphin shall be modeled as a single degree of freedom model. This model will be subjected to a force caused by parallel passing ship. The model is assumed to be in a state of quiet water, this assumption is taken so that the fluid does not provide additional force on the model. The SDOF system shall be analyzed using a computer program designed to solve an ordinary differential equation.

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