Rational polynomial approximation modelling for analysis of structures with ve dampers

Rei Okada, Narutoshi Nakata, B. F. Spencer, Kazuhiko Kasai, Saangbum Kim

Research output: Contribution to journalArticlepeer-review


The objective of this paper is to introduce a Rational Polynomial Approximation (RPA) method for modelling the response of structures that contain discrete elements with linear frequency-dependent stiffness and damping characteristics. The RPA method consists of two steps: First, system identification is performed to obtain a rational polynomial approximation for the system’s transfer functions. Then, a time-domain model for the system is realised. The main advantage of the RPA method is that the resulting model is a system of ordinary differential equations, facilitating time history analysis of both linear and nonlinear structures using standard time-step integration algorithms and procedures. Viscoelastic (VE) dampers comprise one of the primary classes of frequency- dependent dsimpers with both frequency-dependent stiffness and damping. VE dampers are used for mitigation of seismic- and wind-induced structural vibration. When using VE dampers in analysis, effective modelling of the frequency-dependent characteristics of the VE damper plays a key role in accurate simulation of structural responses. Following a description of the theory behind the RPA method, the efficacy of the method is verified through several nunlerical examples employing VE damped structures. The results are compared with Kasai’s fractional derivative model for VE dampersApplication of the RPA method to nonlinear structures is also given. The RPA method is shewn to be effective and efficient for modelling VE damped structure.

Original languageEnglish (US)
Pages (from-to)97-125
Number of pages29
JournalJournal of Earthquake Engineering
Issue number1
StatePublished - Jan 2006


  • Frequency domain system identification
  • Frequency-dependent materials
  • Rational polynomial approximation
  • Time history response analysis
  • Viscoelastic damper

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Geotechnical Engineering and Engineering Geology


Dive into the research topics of 'Rational polynomial approximation modelling for analysis of structures with ve dampers'. Together they form a unique fingerprint.

Cite this