IDENTIFICATION OF HYSTERETIC OSCILLATORS UNDER EARTHQUAKE LOADING BY NONPARAMETRIC MODELS

Nonparametric identification techniques are used to process recorded data of nonlinear structural responses and to represent the constitutive relationship of the structure. When hysteretic systems are dealt with, attention must be given to the appropriate subspace of the state variables in which the restoring force can be approximated by a single-valued surface. Nonparametric models are investigated, defined by two different descriptions: the first, in which the restoring force is a function of displacement and velocity, is commonly used; and the second, in which the incremental force is a function of force and velocity is less adopted. The ability of the second variable space to better reproduce the behavior of hysteretic oscillators is shown by analyzing different cases. Meanwhile, approximation of the real restoring function in terms of orthogonal (Chebyshev) polynomials and nonorthogonal polynomials is investigated. Finally, a mixed parametric and nonparametric model that exhibits a very satisfactory behavior in the case of important hardening and viscous damping is presented.

[1]  Sami F. Masri,et al.  Identification of nonlinear vibrating structures: Part I -- Formulation , 1987 .

[2]  Sami F. Masri,et al.  A Nonparametric Identification Technique for Nonlinear Dynamic Problems , 1979 .

[3]  Edward F. Crawley,et al.  Identification of nonlinear structural elements by force-state mapping , 1984 .

[4]  C.-Y. Peng,et al.  Identification of Hysteretic Structural Behaviour from Strong Motion Accelerograms , 1988 .

[5]  Wilfred D. Iwan,et al.  A model for system identification of degrading structures , 1986 .

[6]  M. Schetzen.  The Volterra and Wiener Theories of Nonlinear Systems , 1980 .

[7]  Sami F. Masri,et al.  Identification of Nonlinear Vibrating Structures: Part II—Applications , 1987 .

[8]  T. Caughey.  Equivalent Linearization Techniques , 1962 .

[9]  Louis Jezequel,et al.  Improvement of a Nonparametric Identification Procedure Used in Nonlinear Dynamics , 1989 .

[10]  Sassan Toussi,et al.  Hysteresis Identification of Existing Structures , 1983 .

[11]  F. E. Udwadia,et al.  Nonparametric identification of a class of nonlinear close-coupled dynamic systems , 1981 .

[12]  Danilo Capecchi,et al.  Accurate solutions and stability criterion for periodic oscillations in hysteretic systems , 1990 .

[13]  M. Yar,et al.  Parameter estimation for hysteretic systems , 1987 .

[14]  T. T. Baber,et al.  Modeling General Hysteresis Behavior and Random Vibration Application , 1986 .

[15]  Edward F. Crawley,et al.  Force-state mapping identification of nonlinear joints , 1987 .

[16]  P. Spanos,et al.  Random vibration and statistical linearization , 1990 .

[17]  O. G. Vinogradov,et al.  Vibrations of a system with non-linear hysteresis , 1986 .

[18]  S. Masri,et al.  Nonparametric Identification of Nearly Arbitrary Nonlinear Systems , 1982 .