Mesoscopic fabric models using a discrete mass-spring approach: Yarn-yarn interactions analysis

2005 ◽  
Vol 40 (22) ◽  
pp. 5925-5932 ◽  
Author(s):  
Bilel Ben Boubaker ◽  
Bernard Haussy ◽  
Jean-Francois Ganghoffer
Keyword(s):  
Mass Spring ◽  
Discrete Mass

ESTIMATION OF DYNAMIC SYSTEM'S EXCITATION FORCES BY THE INDEPENDENT COMPONENT ANALYSIS

2012 ◽  
Vol 04 (03) ◽  
pp. 1250032 ◽  
Author(s):  
ALI AKROUT ◽  
DHOUHA TOUNSI ◽  
MOHAMED TAKTAK ◽  
MOHAMED SLIM ABBÈS ◽  
MOHAMED HADDAR
Keyword(s):  
Independent Component Analysis ◽  
Numerical Procedure ◽  
Component Analysis ◽  
Independent Component ◽  
Dynamic Responses ◽  
Statistical Criterion ◽  
Mass Spring ◽  
Discrete Mass ◽  
Signal Sources ◽  
Good Agreement

This paper deals with a numerical investigation for the estimation of dynamic system's excitation sources using the independent component analysis (ICA). In fact, the ICA concept is an important technique of the blind source separation (BSS) method. In this case, only the dynamic responses of a given mechanical system are supposed to be known. Thus, the main difficulty of such problem resides in the existence of any information about the excitation forces. For this purpose, the ICA concept, which consists on optimizing a fourth-order statistical criterion, can be highlighted. Hence, a numerical procedure based on the signal sources independency in the ICA concept is developed. In this work, the analytical or the finite element (FE) dynamic responses are calculated and exploited in order to identify the excitation forces applied on discrete (mass-spring) and continuous (beam) systems. Then, estimated results obtained by the ICA concept are presented and compared to those achieved analytically or by the FE and the modal recombination methods. Since a good agreement is obtained, this approach can be used when the vibratory responses of a dynamic system are obtained through sensor's measurements.

scholarly journals Simplified Vibration Model and analysis of a single-conductor transmission line with dampers

2016 ◽  
Vol 231 (22) ◽  
pp. 4150-4162 ◽  
Author(s):  
O Barry ◽  
R Long ◽  
DCD Oguamanam
Keyword(s):  
Transmission Line ◽  
Equations Of Motion ◽  
Frequency Equation ◽  
Mode Shapes ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Proposed Model ◽  
Vibration Model ◽  
Mass Spring ◽  
Discrete Mass

A novel model is developed for a vibrating single-conductor transmission line carrying Stockbridge dampers. Experiments are performed to determine the equivalent viscous damping of the damper. This damper is then reduced to an equivalent discrete mass-spring-mass and viscous damping system. The equations of motion of the model are derived using Hamilton’s principle and explicit expressions are determined for the frequency equation, and mode shapes. The proposed model is verified using experimental and finite element results from the literature. This proposed model excellently captures free vibration characteristics of the system and the vibration level of the conductor, but performs poorly in regard to the vibration of the counterweights.

Stability of 2D discrete mass-spring systems with negative stiffness springs

2016 ◽  
Vol 253 (7) ◽  
pp. 1395-1409 ◽  
Author(s):  
M. Esin ◽  
E. Pasternak ◽  
A. V. Dyskin
Keyword(s):  
Negative Stiffness ◽  
Mass Spring ◽  
Discrete Mass

scholarly journals Discrete mass-spring structure identification in nonlocal continuum space-fractional model

2019 ◽  
Vol 134 (9) ◽  
Author(s):  
Krzysztof Szajek ◽  
Wojciech Sumelka
Keyword(s):  
Nonlocal Parameter ◽  
Structure Identification ◽  
Nonlocal Continuum ◽  
Fractional Model ◽  
Optimization Task ◽  
The Masses ◽  
Mass Spring ◽  
Discrete Mass ◽  
Continuum Theories ◽  
First Time

Abstract. This paper considers discrete mass-spring structure identification in a nonlocal continuum space-fractional model, defined as an optimization task. Dynamic (eigenvalues and eigenvectors) and static (displacement field) solutions to discrete and continuum theories are major constituents of the objective function. It is assumed that the masses in both descriptions are equal (and constant), whereas the spring stiffness distribution in a discrete system becomes a crucial unknown. The considerations include a variety of configurations of the nonlocal parameter and the order of the fractional model, which makes the study comprehensive, and for the first time provides insight into the possible properties (geometric and mechanical) of a discrete structure homogenized by a space-fractional formulation.

scholarly journals Approximate Super- and Sub-harmonic Response of a Multi-DOFs System with Local Cubic Nonlinearities under Resonance

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Yang CaiJin
Keyword(s):  
Nonlinear Response ◽  
Numerical Solutions ◽  
Resonance Theory ◽  
Subharmonic Excitation ◽  
Linearized System ◽  
Natural Resonance Theory ◽  
Direct Numerical Integration ◽  
Mass Spring ◽  
Discrete Mass ◽  
Harmonic Resonance

A multi-degree-of-freedom dynamical system with local cubic nonlinearities subjected to super/subharmonic excitation is considered in this paper. The purpose of this paper is to approximate the nonlinear response of system at super/sub harmonic resonance. For many situations, single resonance mode is often observed to be leading as system enters into super/sub harmonic resonance. In this case, the single modal natural resonance theory can be applied to reduce the system model and a simplified model with only a single DOF is always obtained. Thus, an approximate solution and the analytical expression of frequency response relation are then derived using classical perturbation analysis. While the system is controlled by multiple modes, modal analysis for linearized system is used to decide dominant modes. The reduced model governed by these relevant modes is found and results in an approximate numerical solutions. An illustrative example of the discrete mass-spring-damper nonlinear vibration system with ten DOFs is examined. The approximation results are validated by comparing them with the calculations from direct numerical integration of the equation of motion of the original nonlinear system. Comparably good agreements are obtained.

Crack Branching Characteristics at Different Propagation Speeds: From Quasi-Static to Supersonic Regime

2014 ◽  
Vol 81 (12) ◽  
Author(s):  
Y. J. Jia ◽  
B. Liu
Keyword(s):  
Dynamic Fracture ◽  
Circumferential Stress ◽  
Propagation Speed ◽  
Crack Branching ◽  
Classical Dynamic ◽  
Fracture Behaviors ◽  
Supersonic Regime ◽  
Crack Propagation Speed ◽  
Mass Spring ◽  
Discrete Mass

Classical dynamic fracture mechanics predicts that the crack branching occurs when crack propagation speed exceeds a subsonic critical velocity. In this paper, we performed simulations on the dynamic fracture behaviors of idealized discrete mass–spring systems. It is interesting to note that a crack does not branch when traveling at supersonic speed, which is consistent with others' experimental observations. The mechanism for the characteristics of crack branching at different propagation speeds is studied by numerical and theoretical analysis. It is found that for all different speed regimes, the maximum circumferential stress near the crack tip determines the crack branching behaviors.

Simulation and Analysis of Two-Mass Suspension Modification Using MATLAB Programming

2019 ◽  
Vol 3 (1) ◽  
pp. 160-165
Author(s):  
Hendry D. Chahyadi
Keyword(s):  
Vibrational Energy ◽  
State Space Model ◽  
Mass System ◽  
Modeling And Analysis ◽  
The Road ◽  
Final Project ◽  
Quarter Car ◽  
Automotive Suspension ◽  
Mass Spring ◽  
Matlab Programming

The designs of automotive suspension system are aiming to avoid vibration generated by road condition interference to the driver. This final project is about a quarter car modeling with simulation modeling and analysis of Two-Mass modeling. Both existing and new modeling are being compared with additional spring in the sprung mass system. MATLAB program is developed to analyze using a state space model. The program developed here can be used for analyzing models of cars and vehicles with 2DOF. The quarter car modelling is basically a mass spring damping system with the car serving as the mass, the suspension coil as the spring, and the shock absorber as the damper. The existing modeling is well-known model for simulating vehicle suspension performance. The spring performs the role of supporting the static weight of the vehicle while the damper helps in dissipating the vibrational energy and limiting the input from the road that is transmitted to the vehicle. The performance of modified modelling by adding extra spring in the sprung mass system provides more comfort to the driver. Later on this project there will be comparison graphic which the output is resulting on the higher level of damping system efficiency that leads to the riding quality.

scholarly journals Vibro-Acoustical Sensitivities of Stiffened Aircraft Structures Due to Attached Mass-Spring-Dampers with Uncertain Parameters

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 174
Author(s):  
Johannes Seidel ◽  
Stephan Lippert ◽  
Otto von Estorff
Keyword(s):  
System Response ◽  
Fuzzy Arithmetic ◽  
Parameter Uncertainties ◽  
Excitation Spectra ◽  
Radiated Noise ◽  
Linking Elements ◽  
Manufacturing Tolerances ◽  
Suitable Framework ◽  
Mass Spring ◽  
The Impact

The slightest manufacturing tolerances and variances of material properties can indeed have a significant impact on structural modes. An unintentional shift of eigenfrequencies towards dominant excitation frequencies may lead to increased vibration amplitudes of the structure resulting in radiated noise, e.g., reducing passenger comfort inside an aircraft’s cabin. This paper focuses on so-called non-structural masses of an aircraft, also known as the secondary structure that are attached to the primary structure via clips, brackets, and shock mounts and constitute a significant part of the overall mass of an aircraft’s structure. Using the example of a simplified fuselage panel, the vibro-acoustical consequences of parameter uncertainties in linking elements are studied. Here, the fuzzy arithmetic provides a suitable framework to describe uncertainties, create combination matrices, and evaluate the simulation results regarding target quantities and the impact of each parameter on the overall system response. To assess the vibrations of the fuzzy structure and by taking into account the excitation spectra of engine noise, modal and frequency response analyses are conducted.

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