The Experts below are selected from a list of 141 Experts worldwide ranked by ideXlab platform

Stan W. Thomas - One of the best experts on this subject based on the ideXlab platform.

  • MOSFET solid state switching circuit improves the 0 to 99% rise time for framing camera Deflection electronics
    22nd International Congress on High-Speed Photography and Photonics, 1997
    Co-Authors: Anthony T. Rivera, Stan W. Thomas
    Abstract:

    We have improved the 0 to 99% rise time voltage on our 2 frame Deflection Plates from 160 nS to 65 nS with the addition of a peaking circuit that works in conjunction with our primary 2 frame Deflection circuitry. Our peaking technique has applications to other HV pulsers including those which must drive 51 ohm loads. Generally, rise time voltages are measured between 10 and 90%. To minimize the camera image blur resulting from the dynamic influence of Deflection Plate potentials acting on photocathode electrons, it was necessary to design a circuit that would rise from 0 to the 99% voltage level in under 100 nS. Once this voltage was reached, it was necessary to stay within 1% of the attained voltage level for a duration of 1 uS. This was accomplished with the use of MOSFET solid state switching.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

  • MOSFET solid state switching circuit improves the 0 to 99% rise time for framing camera Deflection electronics
    1996
    Co-Authors: Anthony T. Rivera, Stan W. Thomas
    Abstract:

    We have improved the 0 to 99% rise time voltage on our 2 frame Deflection Plates from 160 to 65 nS with the addition of a peaking circuit that works in conjunction with our primary 2 frame Deflection circuitry. Our peaking technique has applications to other HV pulsers including those which must drive 51 ohm loads. Generally, rise time voltages are measured between 10 and 90%. To minimize the camera image blur resulting from the dynamic influence of Deflection Plate potentials acting on photocathode electrons, it was necessary to design a circuit that would rise from 0 to the 99% voltage level in under 100nS. Once this voltage was reached, it was necessary to stay within 1% of the attained voltage level for a duration of 1 uS. This was accomplished with the use of MOSFET solid state switching.

Chaokuang Chen - One of the best experts on this subject based on the ideXlab platform.

  • double mode modeling of chaotic and bifurcation dynamics for a simply supported rectangular Plate in large Deflection
    International Journal of Non-linear Mechanics, 2002
    Co-Authors: Chaokuang Chen
    Abstract:

    This paper presents a new approach to characterize the conditions that can possibly lead to chaotic motion for a simply supported large Deflection rectangular Plate by utilizing the criteria of the fractal dimension and the maximum Lyapunov exponent. The governing partial differential equation of the simply supported rectangular Plate is first derived and simplified to a set of two ordinary differential equations by the Galerkin method. Several different features including Fourier spectra, state-space plot, Poincaŕe map and bifurcation diagram are then numerically computed by using a double-mode approach. These features are used to characterize the dynamic behavior of the Plate subjected to various excitation conditions. Numerical examples are presented to verify the validity of the conditions that lead to chaotic motion and the effectiveness of the proposed modeling approach. The numerical results indicate that large Deflection motion of a rectangular Plate possesses many bifurcation points, two different chaotic motions and some jump phenomena under various lateral loading. The results of numerical simulation indicate that the computed bifurcation points can lead to either a transcritical bifurcation or a pitchfork bifurcation for the motion of a large Deflection rectangular Plate. Meanwhile, the points of pitchfork bifurcation can gradually lead to chaotic motion in some specific loading conditions. The modeling result thus obtained by using the method proposed in this paper can be employed to predict the instability induced by the dynamics of a large Deflection Plate.

Sadok Sassi - One of the best experts on this subject based on the ideXlab platform.

  • Effects Of Initial Geometric Imperfections On The Interaction Between Forced And Parametric Vibrations
    Journal of Sound and Vibration, 1994
    Co-Authors: Sadok Sassi, G.l. Ostiguy
    Abstract:

    Abstract The influence of initial geometric imperfections on the response of simply supported rectangular Plates subjected to periodic in-plane forces is theoretically analyzed in this work. The large Deflection Plate theory used in the analysis is derived in terms of the stress function F and lateral displacement W. The temporal response is analyzed by the first order generalized asymptotic method, and principal parametric and forced resonances are considered and investigated. Interaction between the two types of resonances is found to depend on mode shapes and imperfection amplitudes.

  • Effects of initial geometric imperfections on dynamic behavior of rectangular Plates
    Nonlinear Dynamics, 1992
    Co-Authors: G.l. Ostiguy, Sadok Sassi
    Abstract:

    The present work deals with the influence of initial geometric imperfections on the dynamic behavior of simply supported rectangular Plates subjected to the action of periodic in-plane forces. The nonlinear large-Deflection Plate theory used in this analysis corresponds to the dynamic analog of von Karman's theory. The temporal response is analyzed by the first-order generalized asymptotic method. The solution for the temporal equations of motion takes into account the possibility of existence of simultaneous forced and parametric vibrations. The results indicate that the presence of initial imperfections may significantly raise the resonance frequencies, cause the Plate to exhibit a soft spring behavior and improve slightly the stability of the Plate by reducing the area of its instability zones. Furthermore, the presence of initial imperfections induces forced vibrations which interact with parametric vibrations in order to generate a competitive hesitation phenomenon in the transition zone.

R. Ganesan - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear dynamic instability analysis of laminated composite thin Plates subjected to periodic in-plane loads
    Nonlinear Dynamics, 2017
    Co-Authors: M. Darabi, R. Ganesan
    Abstract:

    In this paper, the dynamic instability of thin laminated composite Plates subjected to harmonic in-plane loading is studied based on nonlinear analysis. The equations of motion of the Plate are developed using von Karman-type of Plate equation including geometric nonlinearity. The nonlinear large Deflection Plate equations of motion are solved by using Galerkin’s technique that leads to a system of nonlinear Mathieu-Hill equations. Dynamically unstable regions, and both stable- and unstable-solution amplitudes of the steady-state vibrations are obtained by applying the Bolotin’s method. The nonlinear dynamic stability characteristics of both antisymmetric and symmetric cross-ply laminates with different lamination schemes are examined. A detailed parametric study is conducted to examine and compare the effects of the orthotropy, magnitude of both tensile and compressive longitudinal loads, aspect ratios of the Plate including length-to-width and length-to-thickness ratios, and in-plane transverse wave number on the parametric resonance particularly the steady-state vibrations amplitude. The present results show good agreement with that available in the literature.

H-s Shen - One of the best experts on this subject based on the ideXlab platform.

  • Dynamic response of initially stressed functionally graded rectangular thin Plates
    Composite Structures, 2001
    Co-Authors: Jie Yang, H-s Shen
    Abstract:

    This paper deals with the dynamic response of initially stressed functionally graded rectangular thin Plates subjected to partially distributed impulsive lateral loads and without or resting on an elastic foundation. Material properties are assumed to be temperature - dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The Plate is assumed to be clamped on two opposite edges and the remaining two edges may be simply supported or clamped or may have elastic rotational edge constraints. The formulation are based on classical small Deflection Plate theory, and account for the Plate-foundation interaction effects by a two-parameter model (Pasternak-type). A one-dimensional differential quadrature approximation and the Galerkin procedure are employed in the free vibration analysis, and the Modal Superposition Method is used to determine the transient response of the Plate structure. A parametric study is carried out. Effects of constituent volume fraction index, foundation stiffness, Plate aspect ratio, the shape and duration of impulsive load, as well as the initial membrane stresses on the dynamic response of FGM Plates are studied. Comprehensive numerical results for silicon nitride/stainless steel rectangular Plates are presented in dimensionless tabular and graphical forms. ?? 2001 Elsevier Science Ltd. All rights reserved.