The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Francesco Basile - One of the best experts on this subject based on the ideXlab platform.

  • massive partition functions and Complex Eigenvalue correlations in matrix models with symplectic symmetry
    Nuclear Physics, 2007
    Co-Authors: Gernot Akemann, Francesco Basile
    Abstract:

    Abstract We compute all massive partition functions or characteristic polynomials and their Complex Eigenvalue correlation functions for non-Hermitean extensions of the symplectic and chiral symplectic ensemble of random matrices. Our results are valid for general weight functions without degeneracies of the mass parameters. The expressions we derive are given in terms of the Pfaffian of skew orthogonal polynomials in the Complex plane and their kernel. They are much simpler than the corresponding expressions for symplectic matrix models with real Eigenvalues, and we explicitly show how to recover these in the Hermitean limit. This explains the appearance of three different kernels as quaternion matrix elements there in terms of derivatives of a single kernel here.

  • Massive partition functions and Complex Eigenvalue correlations in matrix models with symplectic symmetry
    Nuclear Physics B, 2007
    Co-Authors: Gernot Akemann, Francesco Basile
    Abstract:

    We compute all massive partition functions or characteristic polynomials and their Complex Eigenvalue correlation functions for non-Hermitean extensions of the symplectic and chiral symplectic ensemble of random matrices. Our results are valid for general weight functions without degeneracies of the mass parameters. The expressions we derive are given in terms of the Pfaffian of skew orthogonal polynomials in the Complex plane and their kernel. They are much simpler than the corresponding expressions for symplectic matrix models with real Eigenvalues, and we explicitly show how to recover these in the Hermitean limit. This explains the appearance of three different kernels as quaternion matrix elements there in terms of derivatives of a single kernel here. We compare to the Hermitean limit of Complex matrix models with unitary symmetry leading to some determinantal identities.Comment: 24 pages, v2 published version: discussion + refs added, typos corecte

Ajai Sulekh - One of the best experts on this subject based on the ideXlab platform.

  • estimation curve for modal damping in stay cables with viscous damper
    Journal of Structural Engineering-asce, 1993
    Co-Authors: Benito M Pacheco, Yozo Fujino, Ajai Sulekh
    Abstract:

    To simplify the procedure of designing viscous dampers for stay cables in bridges, a universal estimation curve is proposed that relates the modal damping ratio of the cable with attached damper, the mode number, the damper size, the damper location, and three parameters of the cable: span, mass per unit length, and fundamental frequency. The curve is obtained from numerical Complex‐Eigenvalue analysis of a taut cable with a single damper near the anchorage, with judicious grouping of these parameters into nondimensional factors. Several numerical examples illustrate the convenient use of this design aid, as well as show realistic values of the required damper size and location and the expected additional damping in the first few modes. The damping to be attained is usually high enough to suppress most vibrations induced by wind. However it is noted that a small sag of the cable and slight nonviscous properties of the damper may reduce the damper effectiveness. A modified design curve may have to incorpor...

Benito M Pacheco - One of the best experts on this subject based on the ideXlab platform.

  • estimation curve for modal damping in stay cables with viscous damper
    Journal of Structural Engineering-asce, 1993
    Co-Authors: Benito M Pacheco, Yozo Fujino, Ajai Sulekh
    Abstract:

    To simplify the procedure of designing viscous dampers for stay cables in bridges, a universal estimation curve is proposed that relates the modal damping ratio of the cable with attached damper, the mode number, the damper size, the damper location, and three parameters of the cable: span, mass per unit length, and fundamental frequency. The curve is obtained from numerical Complex‐Eigenvalue analysis of a taut cable with a single damper near the anchorage, with judicious grouping of these parameters into nondimensional factors. Several numerical examples illustrate the convenient use of this design aid, as well as show realistic values of the required damper size and location and the expected additional damping in the first few modes. The damping to be attained is usually high enough to suppress most vibrations induced by wind. However it is noted that a small sag of the cable and slight nonviscous properties of the damper may reduce the damper effectiveness. A modified design curve may have to incorpor...

Huajiang Ouyang - One of the best experts on this subject based on the ideXlab platform.

  • A prediction methodology of disk brake squeal using Complex Eigenvalue analysis
    International Journal of Vehicle Design, 2008
    Co-Authors: Abd Rahim Abubakar, Huajiang Ouyang
    Abstract:

    This paper presents a methodology for predicting disk brake squeal using the Finite Element (FE) method whereby a three-dimensional FE model of a real disk brake is validated at the component and assembly levels, and more importantly through contact analysis. Consideration of real surface topography of the friction material in the contact interface model represents a major advancement. Kinetic friction coefficients are determined from squeal tests. Two different friction characteristics with friction damping are simulated. The predicted results show that the refined contact interface model can improve accuracy of prediction and also reduce the number of redundant unstable frequencies.

  • Complex Eigenvalue analysis and dynamic transient analysis in predicting disc brake squeal
    International Journal of Vehicle Noise and Vibration, 2006
    Co-Authors: Abd Rahim Abubakar, Huajiang Ouyang
    Abstract:

    There are typically two different methodologies that can be used to predict squeal in a disc brake, i.e., Complex Eigenvalue analysis and dynamic transient analysis. The positive real parts of Complex Eigenvalues indicate the degree of instability of the disc brake and are thought to associate with squeal occurrence or noise intensity. On the other hand, instability in the disc brake can be identified as an initially divergent vibration response using transient analysis. From the literature it appears that the two approaches were performed separately, and their correlation was not much investigated. In addition, there is more than one way of dealing the frictional contact in a disc brake. This paper explores a proper way of conducting both types of analyses and investigates the correlation between them for a large degree-of-freedom disc brake model. A detailed three-dimensional finite element model of a real disc brake is developed. Three different contact regimes are examined in order to assess the best correlation between the two methodologies.

  • numerical analysis of automotive disc brake squeal a review
    International Journal of Vehicle Noise and Vibration, 2005
    Co-Authors: Huajiang Ouyang, Wayne V Nack, Yongbin Yuan, Frank Chen
    Abstract:

    This paper reviews numerical methods and analysis procedures used in the study of automotive disc brake squeal. It covers two major approaches used in the automotive industry, the Complex Eigenvalue analysis and the transient analysis. The advantages and limitations of each approach are examined. This review can help analysts to choose right methods and make decisions on new areas of method development. It points out some outstanding issues in modelling and analysis of disc brake squeal and proposes new research topics. It is found that the Complex Eigenvalue analysis is still the approach favoured by the automotive industry and the transient analysis is gaining increasing popularity.

Gernot Akemann - One of the best experts on this subject based on the ideXlab platform.

  • massive partition functions and Complex Eigenvalue correlations in matrix models with symplectic symmetry
    Nuclear Physics, 2007
    Co-Authors: Gernot Akemann, Francesco Basile
    Abstract:

    Abstract We compute all massive partition functions or characteristic polynomials and their Complex Eigenvalue correlation functions for non-Hermitean extensions of the symplectic and chiral symplectic ensemble of random matrices. Our results are valid for general weight functions without degeneracies of the mass parameters. The expressions we derive are given in terms of the Pfaffian of skew orthogonal polynomials in the Complex plane and their kernel. They are much simpler than the corresponding expressions for symplectic matrix models with real Eigenvalues, and we explicitly show how to recover these in the Hermitean limit. This explains the appearance of three different kernels as quaternion matrix elements there in terms of derivatives of a single kernel here.

  • Massive partition functions and Complex Eigenvalue correlations in matrix models with symplectic symmetry
    Nuclear Physics B, 2007
    Co-Authors: Gernot Akemann, Francesco Basile
    Abstract:

    We compute all massive partition functions or characteristic polynomials and their Complex Eigenvalue correlation functions for non-Hermitean extensions of the symplectic and chiral symplectic ensemble of random matrices. Our results are valid for general weight functions without degeneracies of the mass parameters. The expressions we derive are given in terms of the Pfaffian of skew orthogonal polynomials in the Complex plane and their kernel. They are much simpler than the corresponding expressions for symplectic matrix models with real Eigenvalues, and we explicitly show how to recover these in the Hermitean limit. This explains the appearance of three different kernels as quaternion matrix elements there in terms of derivatives of a single kernel here. We compare to the Hermitean limit of Complex matrix models with unitary symmetry leading to some determinantal identities.Comment: 24 pages, v2 published version: discussion + refs added, typos corecte