Optimal Design of Sandwich Beam With Frequency Constraints

2007 ◽  
Author(s):  
Vladimir B. Gantovnik ◽  
Alexander V. Lopatin ◽  
Lubov V. Shumkova
Keyword(s):  
Equations Of Motion ◽  
Sandwich Beam ◽  
Vibrational Analysis ◽  
Optimal Parameters ◽  
One Dimensional ◽  
Sandwich Plates And Shells ◽  
Complex Models ◽  
Plates And Shells ◽  
Transversal Vibrations ◽  
Selection Of

In this paper, we analyze selection of optimal parameters of sandwich beam in the presence of constraints on the frequencies of the transversal vibrations. The employed equations of motion take into account the transverse shear deformations in the core and rotatory inertia of the beam cross-section. The expressions for the transversal vibrations are obtained. The results show that one-dimensional model of the sandwich beam can be used for preliminary vibrational analysis of more complex models of sandwich plates and shells.

Selection of one-dimensional sedimentation: models for on-line use

1995 ◽  
Vol 31 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Koen Grijspeerdt ◽  
Peter Vanrolleghem ◽  
Willy Verstraete
Keyword(s):  
Steady State ◽  
Selection Criteria ◽  
Data Sets ◽  
Concentration Profiles ◽  
A Posteriori ◽  
One Dimensional ◽  
On Line ◽  
Dynamic Concentration ◽  
Selection Of ◽  
Modelling Task

A comparative study of several recently proposed one-dimensional sedimentation models has been made. This has been achieved by fitting these models to steady-state and dynamic concentration profiles obtained in a down-scaled secondary decanter. The models were evaluated with several a posteriori model selection criteria. Since the purpose of the modelling task is to do on-line simulations, the calculation time was used as one of the selection criteria. Finally, the practical identifiability of the models for the available data sets was also investigated. It could be concluded that the model of Takács et al. (1991) gave the most reliable results.

Two-dimensional leaps in near-critical flow over isolated orography

2005 ◽  
Vol 461 (2064) ◽  
pp. 3747-3763 ◽  
Author(s):  
E.R Johnson ◽  
G.G Vilenski
Keyword(s):  
Unsteady Flow ◽  
Equations Of Motion ◽  
Fold Increase ◽  
Flow Speed ◽  
Two Dimensional ◽  
Subcritical Flow ◽  
One Dimensional ◽  
Petviashvili Equation ◽  
Lee Wave ◽  
Supercritical Flows

This paper describes steady two-dimensional disturbances forced on the interface of a two-layer fluid by flow over an isolated obstacle. The oncoming flow speed is close to the linear longwave speed and the layer densities, layer depths and obstacle height are chosen so that the equations of motion reduce to the forced two-dimensional Korteweg–de Vries equation with cubic nonlinearity, i.e. the forced extended Kadomtsev–Petviashvili equation. The distinctive feature noted here is the appearance in the far lee-wave wake behind obstacles in subcritical flow of a ‘table-top’ wave extending almost one-dimensionally for many obstacles widths across the flow. Numerical integrations show that the most important parameter determining whether this wave appears is the departure from criticality, with the wave appearing in slightly subcritical flows but being destroyed by two-dimensional effects behind even quite long ridges in even moderately subcritical flow. The wave appears after the flow has passed through a transition from subcritical to supercritical over the obstacle and its leading and trailing edges resemble dissipationless leaps standing in supercritical flow. Two-dimensional steady supercritical flows are related to one-dimensional unsteady flows with time in the unsteady flow associated with a slow cross-stream variable in the two-dimensional flows. Thus the wide cross-stream extent of the table-top wave appears to derive from the combination of its occurrence in a supercritical region embedded in the subcritical flow and the propagation without change of form of table-top waves in one-dimensional unsteady flow. The table-top wave here is associated with a resonant steepening of the transition above the obstacle and a consequent twelve-fold increase in drag. Remarkably, the table-top wave is generated equally strongly and extends laterally equally as far behind an axisymmetric obstacle as behind a ridge and so leads to subcritical flows differing significantly from linear predictions.

scholarly journals Effect of Thrust on the Structural Vibrations of a Nonuniform Slender Rocket

2020 ◽  
Vol 25 (2) ◽  
pp. 29
Author(s):  
Desmond Adair ◽  
Aigul Nagimova ◽  
Martin Jaeger
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Approximate Solutions ◽  
Mode Shapes ◽  
Algebraic Equations ◽  
Structural Vibrations ◽  
Unknown Parameters ◽  
One Dimensional ◽  
Vibration Problems ◽  
Nonuniform Beam

The vibration characteristics of a nonuniform, flexible and free-flying slender rocket experiencing constant thrust is investigated. The rocket is idealized as a classic nonuniform beam with a constant one-dimensional follower force and with free-free boundary conditions. The equations of motion are derived by applying the extended Hamilton’s principle for non-conservative systems. Natural frequencies and associated mode shapes of the rocket are determined using the relatively efficient and accurate Adomian modified decomposition method (AMDM) with the solutions obtained by solving a set of algebraic equations with only three unknown parameters. The method can easily be extended to obtain approximate solutions to vibration problems for any type of nonuniform beam.

scholarly journals Electric Discharge Grinding of Polycrystalline Diamond Materials

2012 ◽  
Vol 271-272 ◽  
pp. 333-337 ◽  
Author(s):  
Song Lin Ding ◽  
John P.T. Mo ◽  
Milan Brandt ◽  
Richard Webb
Keyword(s):  
Electrical Discharge ◽  
Material Removal ◽  
Working Condition ◽  
Removal Rate ◽  
Polycrystalline Diamond ◽  
Optimal Parameters ◽  
Power Generator ◽  
The Poor ◽  
Edm Process ◽  
Selection Of

The poor electric conductivity of polycrystalline diamond (PCD) makes it difficult to machine with the conventional EDM process. Inappropriate selection of parameters of the power generator and the servo system leads to unstable working condition and low material removal rate. This paper introduces a method to find optimal parameters in the Electrical Discharge Grinding (EDG) of PCD materials with Taguchi method. The theory and detailed procedures are presented, experimental results are analyzed. The optimized configuration was validated through confirmation tests.

Modal Loss Factor Predication in Flexible Mechanism Systems With Constrain Viscoelastic Layers

1998 ◽  
Author(s):  
Zhang Xianmin ◽  
Liu Jike
Keyword(s):  
Equations Of Motion ◽  
Sandwich Beam ◽  
Viscoelastic Layer ◽  
Treatment Technique ◽  
Constrained Layer Damping ◽  
Modal Strain Energy ◽  
Frame Element ◽  
Modal Damping ◽  
Flexible Mechanism ◽  
Viscoelastic Layers

Abstract Control of dynamic vibration is critical to the operational success of many flexible mechanism systems. This paper addresses the problem of vibration control of such mechanisms through passive damping, using constrained layer damping treatment technique. A new type of shape function for three layer frame element containing a viscoelastic layer is developed. The equations of motion of the damped flexible mechanism are derived. Modal loss factors of this kind mechanisms are predicated from undamped normal mode by means of the modal strain energy method. Comparisons between the results obtained by this paper and the results obtained by exact solution of the governing equations for a well known sandwich beam demonstrate that the method presented in this paper is correct and reliable. Application of this method in predication of modal damping ratios for damped mechanisms is discussed. It is believed that the method of this paper hold the greatest potential for optimal design of damped flexible mechanism systems.

A short ethnography of twenty-first century consumers: On retail rage and one-dimensionality

2021 ◽  
pp. 146954052110396
Author(s):  
Kevin P. Bingham
Keyword(s):  
Consumer Culture ◽  
Retail Trade ◽  
First Century ◽  
One Dimensional ◽  
Unique Position ◽  
Material Goods ◽  
Twenty First Century ◽  
Selection Of ◽  
Sociological Interpretation ◽  
The Way

This article begins with two central ideas – that feelings of rage appear to be on the increase in present modernity and that one of the main sources of rage is directly linked to consumer culture and the retail experience it fosters. Although retail trade allows twenty-first century individuals to spend their money on material goods and experiences which provide structure and a sense of meaning and belonging, what it also causes is ambivalence, insecurity and anxiety. These are formidable feelings that cause irritation, frustration and anger to gradually fester until it accumulates into something violent that distorts the way an individual thinks, acts and treats other people. With these points in mind, what this article provides is a thorough sociological interpretation of twenty-first century retail rage. Veering away from existing interpretations of rage by drawing on Herbert Marcuse’s analysis and image of a one-dimensional society, what this article explores is the idea that retail experiences turn people into individuals who are bound and controlled by a consumer duty. As I contend, based on my unique position as a researcher turned retail worker, it is this administered, one-dimensional kind of lifestyle that cultivates rage. To support my argument and understand more comprehensively how and why retail breeds frustration and anger, I use a selection of narrative episodes to unpack three key sources of consumer rage in the twenty-first century. These sources have been labelled instantaneity, performativity and unfulfillment.

Dynamics of Spinning Disc Parametrically Excited by Noise

1999 ◽  
Author(s):  
Narayanan Ramakrishnan ◽  
N. Sri Namachchivaya
Keyword(s):  
Equations Of Motion ◽  
Planck Equation ◽  
Stochastic Averaging ◽  
Transverse Motion ◽  
Probability Density Distribution ◽  
Integral Of Motion ◽  
Parametrically Excited ◽  
One Dimensional ◽  
Small Intensity ◽  
Spinning Disc

Abstract The nonlinear dynamics of a circular spinning disc parametrically excited by noise of small intensity is investigated. The governing PDEs are reduced using a Galerkin reduction procedure to a two-DOF system of ODEs which, govern the transverse motion of the disc. The dynamics is simplified by exploiting the S1 invariance of the equations of motion of the reduced system and further, reduced by performing stochastic averaging. The resulting one-dimensional Markov diffusive process is studied in detail. The stationary probability density distribution is obtained by solving the Fokker-Planck equation along with the appropriate boundary conditions. The boundary behaviour is studied using an asymptotic approach. Some aspects of dynamical and phenomenological bifurcations of the stationary solution are also investigated. The scheme of things presented here can be applied in principle to a four-dimensional Hamiltonian system possessing one integral of motion in addition to the hamiltonian and having one fixed point.

On buckling and free vibration studies of sandwich plates and cylindrical shells: A review

2018 ◽  
Vol 33 (5) ◽  
pp. 673-724 ◽  
Author(s):  
Pavan Kumar ◽  
CV Srinivasa
Keyword(s):  
Free Vibration ◽  
Laminated Composite ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
Future Research ◽  
Sandwich Plates ◽  
Composite Sandwich ◽  
Sandwich Plates And Shells ◽  
Graded Material ◽  
Plates And Shells

Many review articles were published on free vibration and buckling of laminated composites, sandwich plates, and shells. The present article reviews the literature on the buckling and free vibration analysis of shear deformable isotropic and laminated composite sandwich plates and shells using various methods available for plates in the past few decades. Various theories, finite element modeling, and experimentations have been reported for the analysis of sandwich plates and shells. Few papers on functionally graded material plates, plates with smart skin (electrorheological, magnetorheological, and piezoelectric), and also viscoelastic materials were also reviewed. The scope for future research on sandwich plates and shells was also accessed.

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