Dynamic Response of a Beam With a Geometric Nonlinearity

1981 ◽  
Vol 48 (2) ◽  
pp. 404-410 ◽  
Author(s):  
S. F. Masri ◽  
Y. A. Mariamy ◽  
J. C. Anderson
Keyword(s):  
Dynamic Response ◽  
Mechanical Model ◽  
Geometric Nonlinearity ◽  
Experimental Studies ◽  
Harmonic Excitation ◽  
Random Excitation ◽  
System Response ◽  
Experimental Measurements ◽  
Euler Beam ◽  
Practical Engineering

Analytical and experimental studies were made of the dynamic response of a system with a geometric nonlinearity, which is encountered in many practical engineering applications. An exact solution was derived for the steady-state motion of a viscously damped Bernoulli-Euler beam with an unsymmetric geometric nonlinearity, under the action of harmonic excitation. Experimental measurements of a mechanical model under harmonic as well as random excitation verified the analytical findings. The effect of various dimensionless parameters on the system response was determined.

Transfer Function of a Class of Nonlinear Multidegree of Freedom Oscillators

1987 ◽  
Vol 54 (1) ◽  
pp. 215-225 ◽  
Author(s):  
L. E. Galhoud ◽  
S. F. Masri ◽  
J. C. Anderson
Keyword(s):  
Exact Solution ◽  
Mechanical Model ◽  
Geometric Nonlinearity ◽  
Experimental Studies ◽  
Harmonic Excitation ◽  
System Response ◽  
Distributed Parameter ◽  
Experimental Measurements ◽  
Practical Engineering ◽  
Two Degree Of Freedom

Analytical and experimental studies were made of the dynamic response of a multidegree-of-freedom system with a geometric nonlinearity, which is encountered in many practical engineering applications. An exact solution was derived for the steady-state motion of a viscously damped two-degree-of-freedom oscillator with an unsymmetric geomtric nonlinearity, under the action of harmonic excitation. Experimental measurements of a distributed-parameter mechanical model under harmonic excitation verified the analytical findings. The effect of various dimensionless parameters on the system response was determined.

Analytical and Experimental Studies of a Dynamic System With a Gap

1978 ◽  
Vol 100 (3) ◽  
pp. 480-486 ◽  
Author(s):  
S. F. Masri
Keyword(s):  
Experimental Study ◽  
Dynamic System ◽  
Mechanical Model ◽  
Experimental Studies ◽  
Harmonic Excitation ◽  
Resonance Phenomenon ◽  
Mechanical Equipment ◽  
Experimental Measurements ◽  
System Parameters ◽  
Closed Form Analytical Solution

An analytical and experimental study is made of the forced vibration of a dynamic system with a motion-limiting stop, which is encountered in many practical cases involving mechanical equipment. An exact closed-form analytical solution is derived for the steady-state motion of the system when it is subjected to harmonic excitation. Experimental measurements with a mechanical model verify the analytical findings. The effects of various system parameters on the response are determined. Some interesting features of the motion are observed and compared to the jump resonance phenomenon exhibited by the solution of Duffing’s equation.

scholarly journals The Dynamic Response of Tuned Impact Absorbers for Rotating Flexible Structures

2005 ◽  
Vol 1 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Steven W. Shaw ◽  
Christophe Pierre
Keyword(s):  
Dynamic Response ◽  
Flexible Structures ◽  
Experimental Studies ◽  
Analytical Investigation ◽  
Design Parameters ◽  
System Response ◽  
Rotor Speed ◽  
Flexible System ◽  
Restoring Forces ◽  
And Performance

This paper describes an analytical investigation of the dynamic response and performance of impact vibration absorbers fitted to flexible structures that are attached to a rotating hub. This work was motivated by experimental studies at NASA, which demonstrated the effectiveness of these types of absorbers for reducing resonant transverse vibrations in periodically excited rotating plates. Here we show how an idealized model can be used to describe the essential dynamics of these systems, and used to predict absorber performance. The absorbers use centrifugally induced restoring forces so that their nonimpacting dynamics are tuned to a given order of rotation, whereas their large amplitude dynamics involve impacts with the primary flexible system. The linearized, nonimpacting dynamics are first explored in detail, and it is shown that the response of the system has some rather unique features as the hub rotor speed is varied. A class of symmetric impacting motions is also analyzed and used to predict the effectiveness of the absorber when operating in its impacting mode. It is observed that two different types of grazing bifurcations take place as the rotor speed is varied through resonance, and their influence on absorber performance is described. The analytical results for the symmetric impacting motions are also used to generate curves that show how important absorber design parameters—including mass, coefficient of restitution, and tuning—affect the system response. These results provide a method for quickly evaluating and comparing proposed absorber designs.

Simple Harmonic Excitation Numerical Analysis and Experimental Study of Space Bidirectional Beam String Structure

2011 ◽  
Vol 368-373 ◽  
pp. 3-11
Author(s):  
Cheng Jie Ye ◽  
Zao Liang Gao
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Dynamic Response ◽  
Experimental Studies ◽  
Time History ◽  
Theoretical Data ◽  
Harmonic Excitation ◽  
Space Harmonic ◽  
Finite Element Software ◽  
Design And Construction

In this paper,a two-way winding-beam space-harmonic excitation beam string under the action of the dynamic response has been studied to capture the dynamic response of the structure of the law, identify the structure of the weak components,and for the design and construction to provide the necessary theoretical data. Using ANSYS finite element software to numerical analysis and reduced scale quarter ratio of model test research methodology to study,using experimental test results and finite element numerical analysis of mutual authentication.Numerical analysis taking into account the geometric non-linear structure,carried out static analysis,modal analysis,harmonic analysis and transient response time-history analysis. Experimental studies of the dynamic signal acquisition and analysis and processing, through the comparative analysis of data, master of the winding space for a two-way steel beam string dynamic response law obtained structural response of the frequency response range,weak location and distribution of components of type of structural design and construction process were proposed.

Dynamic Response and Identification of Tower-Cable-Roller Battery Interactions in Ropeways

2017 ◽  
Author(s):  
Andrea Arena ◽  
Biagio Carboni ◽  
Walter Lacarbonara ◽  
Mathieu Babaz
Keyword(s):  
Dynamic Response ◽  
Mechanical Model ◽  
Transportation Systems ◽  
System Response ◽  
High Fidelity ◽  
Custom Design ◽  
Nonlinear Mechanical ◽  
Frequency Domain Decomposition ◽  
Dynamical Description ◽  
Enhanced Frequency Domain Decomposition

Towers, roller batteries, propelling cables and vehicles are the substructures of ropeway transportation systems. High-fidelity modeling of their dynamical interactions together with a reliable identification is a key step towards the prediction of the system response under various transit conditions as well as to investigate design optimization strategies. In this work, a nonlinear mechanical model for the dynamical description of cablecar ski lift systems is discussed. The investigation is focused on the modal features and the forced dynamic response caused by the vehicles transit across the so-called compression towers. The model is validated according to experimental data acquired via a custom-design sensor network. The Enhanced Frequency Domain Decomposition (EFDD) method is employed to identify the frequencies and damping ratios.

Experimental Studies of Sedimentation Basin Dynamics

1977 ◽  
Vol 12 (1) ◽  
pp. 77-90
Author(s):  
J.F. Cordoba-Molina ◽  
P.L. Silveston ◽  
R. R. Hudgins
Keyword(s):  
Dynamic Response ◽  
Froude Number ◽  
Flow Model ◽  
Experimental Studies ◽  
Densimetric Froude Number ◽  
Number Range ◽  
The Real ◽  
Highly Correlated ◽  
Sedimentation Basins ◽  
Simple Flow

Abstract A simple Flow Model is proposed to describe the dynamic response of sedimentation basins. The response predicted by this model is linear as opposed to the real response of the basin which is nonlinear. However, the real response of the basin is highly correlated with its densimetric Froude number, and as a consequence our linear model effectively predicts the response of the basin in a restricted densimetric Froude Number range. Our experiments show that the response of the basin becomes more sluggish and erratic as the densimetric Froude number decreases.

Vibrations of Foundations Interacting With Subsoil Experimental Studies and BE Calculations

1991 ◽  
Author(s):  
L. Gaul
Keyword(s):  
Boundary Element Method ◽  
Dynamic Response ◽  
Surface Waves ◽  
Boundary Element ◽  
Constitutive Equations ◽  
Experimental Studies ◽  
Boundary Elements ◽  
Experimental Techniques ◽  
Embedded Structures ◽  
Element Method

Abstract Calculation of the dynamic response of sensitive structures like foundations for vibrating machinery requires to take the interaction with subsoil into account. Structures and soil are discretized by boundary elements and coupled by a substructure technique. Viscoelastic constitutive equations contain fractional time derivatives. Surface waves generated by machine foundations and diffracted by embedded structures and soil inhomogeneities are analyzed by conventional and optoelectronic experimental techniques and calculated by the boundary element method (BEM).

scholarly journals Research on Formation Mechanism of Dynamic Response and Residual Stress of Sheet Metal Induced by Laser Shock Wave

2018 ◽  
Vol 167 ◽  
pp. 05007
Author(s):  
Aixin Feng ◽  
Yupeng Cao ◽  
Heng Wang ◽  
Zhengang Zhang
Keyword(s):  
Shock Wave ◽  
Residual Stress ◽  
Dynamic Response ◽  
Formation Mechanism ◽  
Experimental Studies ◽  
Material Surface ◽  
Propagation Mechanism ◽  
Laser Shock ◽  
Surface Residual Stress ◽  
Laser Shock Wave

In order to reveal the quantitative control of the residual stress on the surface of metal materials, the relevant theoretical and experimental studies were carried out to investigate the dynamic response of metal thin plates and the formation mechanism of residual stress induced by laser shock wave. In this paper, the latest research trends on the surface residual stress of laser shock processing technology were elaborated. The main progress of laser shock wave propagation mechanism and dynamic response, laser shock, and surface residual stress were discussed. It is pointed out that the multi-scale characterization of laser and material, surface residual stress and microstructure change is a new hotspot in laser shock strengthening technology.

An optimal control method for time-delay feedback control of 1/4 vehicle active suspension under random excitation

2021 ◽  
pp. 146134842110592
Author(s):  
Kaiwei Wu ◽  
Chuanbo Ren ◽  
Yuanchang Chen
Keyword(s):  
Time Delay ◽  
Feedback Control ◽  
Control Method ◽  
Harmonic Excitation ◽  
Random Excitation ◽  
Vehicle Body ◽  
Vehicle Suspension ◽  
Control Parameters ◽  
Damping Effect ◽  
Delay Feedback Control

Time-delay feedback control can effectively broaden the damping frequency band and improve the damping efficiency. However, the existing time-delay feedback control strategy has no obvious effect on multi-frequency random excitation vibration reduction control. That is, when the frequency of external excitation is more complicated, there is no better way to obtain the best time-delay feedback control parameters. To overcome this issue, this paper is the first work of proposing an optimal calculation method that introduces stochastic excitation into the process of solving the delay feedback control parameters. It is a time-delay control parameter with a better damping effect for random excitation. In this paper, a 2 DOF one-quarter vehicle suspension model with time-delay is studied. First, the stability interval of time-delay feedback control parameters is solved by using the Lyapunov stability theory. Second, the optimal control parameters of the time-delay feedback control under random excitation are solved by particle swarm optimization (PSO). Finally, the simulation models of a one-quarter vehicle suspension simulation model are established. Random excitation and harmonic excitation are used as inputs. The response of the vehicle body under the frequency domain damping control method and the proposed control method is compared and simulated. To make the control precision higher and the solution speed faster, this paper simulates the model by using the precise integration method of transient history. The simulation results show that the acceleration of the vehicle body in the proposed control method is 13.05% less than the passive vibration absorber under random excitation. Compared with the time-delay feedback control optimized by frequency response function, the damping effect is 12.99%. The results show that the vibration displacement, vibration velocity, and vibration acceleration of the vehicle body are better than the frequency domain function optimization method, whether it is harmonic excitation or random excitation. The ride comfort of the vehicle is improved obviously. It provides a valuable tool for time-delay vibration reduction control under random excitation.

Micromechanical Analysis of Nonlinear Response of Unidirectional Composites: A Fundamental Approach

2001 ◽  
Author(s):  
Virendra R. Jadhav ◽  
Srinivasan Sridharan
Keyword(s):  
Mechanical Model ◽  
Nonlinear Response ◽  
Experimental Studies ◽  
Matrix Cracking ◽  
Type Model ◽  
Unidirectional Composites ◽  
The Matrix ◽  
Experimental Response ◽  
Square Cells ◽  
Experimental Comparisons

Abstract Micromechanical models with different representative volume elements have been developed to study their ability to predict nonlinear response of unidirectional composites. A simple, square cells type micro-mechanical model similar to those widely used by other researchers is compared with a more advanced 3-phase finite element based micro-mechanical model. The models utilize the “bulk” properties of the matrix without attempting to “tune” the model to fit with experimental response of laminae. This is a more fundamental approach and constitutes a departure from current practice. The models account for shear softening, matrix cracking and the presence of residual stresses. A smeared cracking approach was used to characterize the micro-cracking in matrix. Experimental studies were performed on laminae, laminates and cylinders made from carbon epoxy composites. Experimental comparisons show that the more accurate micro-mechanical model with proper partial cracking options provides good bounds on experimental response with consistent accuracy. A square cells type model however is not consistent in its predictions, thus raising questions about its applicability in any general micro-mechanics based analysis.

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