The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Kumar K. Tamma - One of the best experts on this subject based on the ideXlab platform.

  • Instantaneous response of elastic Thin‐Walled Structures to rapid heating
    International Journal for Numerical Methods in Engineering, 1994
    Co-Authors: Xiaoqin Chen, Ram V. Mohan, Kumar K. Tamma
    Abstract:

    A generalized modelling and analysis approach of thermally induced coupled vibrations of elastic Thin-Walled configurations with arbitrary open cross-sections are presented in conjunction with a unified implicit transient methodology. Limited research which takes into account the influence of rapid thermal heating effects on Structures involving various forms of coupling appears in the literature. As a consequence, the dynamic response of such Thin-Walled Structures of arbitrary open cross-section to rapid heating are described here. Effects involving triple, double, and no coupling between bending and torsional vibrations caused by sudden heating on these Structures are examined. Numerical test cases are presented which describe the influence of sudden heating on elastic Thin-Walled Structures of arbitrary open cross-sections.

  • Dynamic response of elastic Thin-Walled Structures influenced by coupling effects
    Computers & Structures, 1994
    Co-Authors: Xiaoqin Chen, Kumar K. Tamma
    Abstract:

    Abstract The present paper describes the dynamic coupled vibrations of elastic Thin-Walled Structures of arbitrary open cross-section influenced by various forms of coupling. The formulations employ Vlasov's assumptions and both warping and rotary inertia are included in the present developments. Because of the complex nature of such problems, the finite element method is employed in conjunction with an implicit self-starting unconditionally stable methodology for the dynamic computations. Three types of test examples dealing with triple, double, and no coupling are described to illustrate the effects of coupling and rotary inertia on the dynamic behavior of Thin-Walled Structures.

  • Instantaneous response of elastic Thin-Walled Structures with arbitrary open cross section to rapid heating
    33rd Structures Structural Dynamics and Materials Conference, 1992
    Co-Authors: Xiaoqin Chen, Ram V. Mohan, Kumar K. Tamma
    Abstract:

    A generalized modeling and analysis approach of thermally-induced coupled vibrations of elastic Thin-Walled configurations with arbitrary open cross sections are presented in conjunction with a unified implicit transient methodology. Limited research appears in literature which takes into account the influence of rapid thermal heating effects on Structures involving various forms of coupling. As a consequence, the dynamic response of such Thin-Walled Structures of arbitrary open cross section due to rapid heating are described here. Effects involving triple, double, and no coupling between bending and torsional vibrations caused by sudden heating on these Structures are examined. Numerical test cases are presented which describe the influence of sudden heating on elastic Thin-Walled Structures of arbitrary open cross sections.

Mannur J. Sundaresan - One of the best experts on this subject based on the ideXlab platform.

  • Space–wavenumber and time–frequency analysis for damage inspection of Thin-Walled Structures:
    Structural Health Monitoring-an International Journal, 2012
    Co-Authors: P. Frank Pai, Mannur J. Sundaresan
    Abstract:

    This article presents a dynamics-based methodology for accurate damage inspection of Thin-Walled Structures by combining a boundary effect evaluation method (BEEM) for space–wavenumber analysis of measured operational deflection shapes (ODSs) and a conjugate-pair decomposition (CPD) method for time–frequency analysis of time traces of measured points. BEEM is for locating and estimating small structural damages by processing ODSs measured by a full-field measurement system (e.g. a scanning laser vibrometer or a camera-based motion measurement system). BEEM is a nondestructive spatial domain method based on sliding-window processing of ODSs, and it works without using any structural model or historical data for comparison. Similar to the short-time Fourier transform and wavelet transform, CPD uses adaptive windowed regular harmonics and function orthogonality to perform time–frequency analysis of time traces by extracting time-localized regular and/or distorted harmonics. Both BEEM and CPD are local spectr...

  • Time-frequency and space-wavenumber analysis for damage inspection of Thin-Walled Structures
    Proceedings of SPIE, 2011
    Co-Authors: P. Frank Pai, Mannur J. Sundaresan
    Abstract:

    This paper presents a dynamics-based methodology for accurate damage inspection of Thin-Walled Structures by combining a boundary-effect evaluation method (BEEM) for space-wavenumber analysis of measured operational deflection shapes (ODSs) and a conjugate-pair decomposition (CPD) method for time-frequency analysis of time traces of measured points. BEEM is for locating and estimating small structural damage by processing ODSs measured by a full-field measurement system (e.g., a scanning laser vibrometer or a camera-based motion measurement system). BEEM is a nondestructive spatial-domain method based on area-by-area processing of ODSs and it works without using any structural model or historical data for comparison. Similar to the short-time Fourier transform and wavelet transform, CPD uses adaptive windowed regular harmonics and function orthogonality to perform time-frequency analysis of time traces by extracting time-localized regular and/or distorted harmonics. Both BEEM and CPD are local spectral analysis based on local, adaptive curve fitting. The first estimation of the wavenumber for BEEM and the frequency for CPD is obtained by using a four-point Teager-Kaiser algorithm based on the use of finite difference. Numerical simulations and experimental results show that the combination of BEEM and CPD for space-wavenumber and time-frequency analysis provides an accurate tool for damage inspection of Thin-Walled Structures.

Robert E. Dick - One of the best experts on this subject based on the ideXlab platform.

  • A new axi-symmetric element for Thin Walled Structures
    Computational Mechanics, 2009
    Co-Authors: Rui P R Cardoso, Jeong Whan Yoon, Robert E. Dick
    Abstract:

    A new axi-symmetric finite element for Thin Walled Structures is presented in this work. It uses the solid-shell element’s concept with only a single element and multiple integration points along the thickness direction. The cross-section of the element is composed of four nodes with two degrees of freedom each. The proposed formulation overcomes many locking pathologies including transverse shear locking, Poisson’s locking and volumetric locking. For transverse shear locking, the formulation uses the selective reduced integration technique, for Poisson’s locking it uses the enhanced assumed strain (EAS) method with only one enhancing variable. The B-bar approach is used to eliminate the isochoric deformations in the hourglass field while the EAS method is used to alleviate the volumetric locking in the constant part of the deformation tensor. Several examples are shown to demonstrate the performance and accuracy of the proposed element with special focus on the numerical simulations for the beverage can industry.

  • A new axi-symmetric element for Thin Walled Structures
    Computational Mechanics, 2009
    Co-Authors: Rui P R Cardoso, Jeong Whan Yoon, Robert E. Dick
    Abstract:

    A new axi-symmetric finite element for Thin Walled Structures is presented in this work. It uses the solid-shell element’s concept with only a single element and multiple integration points along the thickness direction. The cross-section of the element is composed of four nodes with two degrees of freedom each. The proposed formulation overcomes many locking pathologies including transverse shear locking, Poisson’s locking and volumetric locking. For transverse shear locking, the formulation uses the selective reduced integration technique, for Poisson’s locking it uses the enhanced assumed strain (EAS) method with only one enhancing variable. The B-bar approach is used to eliminate the isochoric deformations in the hourglass field while the EAS method is used to alleviate the volumetric locking in the constant part of the deformation tensor. Several examples are shown to demonstrate the performance and accuracy of the proposed element with special focus on the numerical simulations for the beverage can industry.

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

  • Instantaneous response of elastic Thin‐Walled Structures to rapid heating
    International Journal for Numerical Methods in Engineering, 1994
    Co-Authors: Xiaoqin Chen, Ram V. Mohan, Kumar K. Tamma
    Abstract:

    A generalized modelling and analysis approach of thermally induced coupled vibrations of elastic Thin-Walled configurations with arbitrary open cross-sections are presented in conjunction with a unified implicit transient methodology. Limited research which takes into account the influence of rapid thermal heating effects on Structures involving various forms of coupling appears in the literature. As a consequence, the dynamic response of such Thin-Walled Structures of arbitrary open cross-section to rapid heating are described here. Effects involving triple, double, and no coupling between bending and torsional vibrations caused by sudden heating on these Structures are examined. Numerical test cases are presented which describe the influence of sudden heating on elastic Thin-Walled Structures of arbitrary open cross-sections.

  • Dynamic response of elastic Thin-Walled Structures influenced by coupling effects
    Computers & Structures, 1994
    Co-Authors: Xiaoqin Chen, Kumar K. Tamma
    Abstract:

    Abstract The present paper describes the dynamic coupled vibrations of elastic Thin-Walled Structures of arbitrary open cross-section influenced by various forms of coupling. The formulations employ Vlasov's assumptions and both warping and rotary inertia are included in the present developments. Because of the complex nature of such problems, the finite element method is employed in conjunction with an implicit self-starting unconditionally stable methodology for the dynamic computations. Three types of test examples dealing with triple, double, and no coupling are described to illustrate the effects of coupling and rotary inertia on the dynamic behavior of Thin-Walled Structures.

  • Instantaneous response of elastic Thin-Walled Structures with arbitrary open cross section to rapid heating
    33rd Structures Structural Dynamics and Materials Conference, 1992
    Co-Authors: Xiaoqin Chen, Ram V. Mohan, Kumar K. Tamma
    Abstract:

    A generalized modeling and analysis approach of thermally-induced coupled vibrations of elastic Thin-Walled configurations with arbitrary open cross sections are presented in conjunction with a unified implicit transient methodology. Limited research appears in literature which takes into account the influence of rapid thermal heating effects on Structures involving various forms of coupling. As a consequence, the dynamic response of such Thin-Walled Structures of arbitrary open cross section due to rapid heating are described here. Effects involving triple, double, and no coupling between bending and torsional vibrations caused by sudden heating on these Structures are examined. Numerical test cases are presented which describe the influence of sudden heating on elastic Thin-Walled Structures of arbitrary open cross sections.

P. Frank Pai - One of the best experts on this subject based on the ideXlab platform.

  • Space–wavenumber and time–frequency analysis for damage inspection of Thin-Walled Structures:
    Structural Health Monitoring-an International Journal, 2012
    Co-Authors: P. Frank Pai, Mannur J. Sundaresan
    Abstract:

    This article presents a dynamics-based methodology for accurate damage inspection of Thin-Walled Structures by combining a boundary effect evaluation method (BEEM) for space–wavenumber analysis of measured operational deflection shapes (ODSs) and a conjugate-pair decomposition (CPD) method for time–frequency analysis of time traces of measured points. BEEM is for locating and estimating small structural damages by processing ODSs measured by a full-field measurement system (e.g. a scanning laser vibrometer or a camera-based motion measurement system). BEEM is a nondestructive spatial domain method based on sliding-window processing of ODSs, and it works without using any structural model or historical data for comparison. Similar to the short-time Fourier transform and wavelet transform, CPD uses adaptive windowed regular harmonics and function orthogonality to perform time–frequency analysis of time traces by extracting time-localized regular and/or distorted harmonics. Both BEEM and CPD are local spectr...

  • Time-frequency and space-wavenumber analysis for damage inspection of Thin-Walled Structures
    Proceedings of SPIE, 2011
    Co-Authors: P. Frank Pai, Mannur J. Sundaresan
    Abstract:

    This paper presents a dynamics-based methodology for accurate damage inspection of Thin-Walled Structures by combining a boundary-effect evaluation method (BEEM) for space-wavenumber analysis of measured operational deflection shapes (ODSs) and a conjugate-pair decomposition (CPD) method for time-frequency analysis of time traces of measured points. BEEM is for locating and estimating small structural damage by processing ODSs measured by a full-field measurement system (e.g., a scanning laser vibrometer or a camera-based motion measurement system). BEEM is a nondestructive spatial-domain method based on area-by-area processing of ODSs and it works without using any structural model or historical data for comparison. Similar to the short-time Fourier transform and wavelet transform, CPD uses adaptive windowed regular harmonics and function orthogonality to perform time-frequency analysis of time traces by extracting time-localized regular and/or distorted harmonics. Both BEEM and CPD are local spectral analysis based on local, adaptive curve fitting. The first estimation of the wavenumber for BEEM and the frequency for CPD is obtained by using a four-point Teager-Kaiser algorithm based on the use of finite difference. Numerical simulations and experimental results show that the combination of BEEM and CPD for space-wavenumber and time-frequency analysis provides an accurate tool for damage inspection of Thin-Walled Structures.