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Dynamic response of an elastic‐viscoplastic system in modal co‐ordinates
Author(s) -
Lukkunaprasit Panitan,
Widartawan Stephen,
Karasudhi Pisidhi
Publication year - 1980
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290080304
Subject(s) - viscoplasticity , modal , displacement (psychology) , computation , modal analysis , equations of motion , structural engineering , mathematical analysis , mathematics , constitutive equation , mechanics , finite element method , physics , classical mechanics , materials science , engineering , algorithm , psychology , polymer chemistry , psychotherapist
A dynamic analysis of elastic–viscoplastic systems, incorporating the modal co‐ordinate transformation technique, is presented. The formulation results in uncoupled incremental equations of motion with respect to the modal co‐ordinates. The elastic–viscoplastic model adopted allows the analysis not to involve yielding regions and loading/unloading processes. An implicit Runge–Kutta scheme together with the Newton–Raphson method are used to solve the non‐linear constitutive equations. Stability and accuracy of the numerical solution are improved by utilizing a local time step sub‐incrementing procedure. Applications of the analyses to multi‐storey shear buildings show that good results can be obtained for the maximum displacement response by including only a few lower modes in the computation, but the prediction of the ductility factor response tends to underestimate the peak values when too few modes are used. In addition, stable and valid results can be obtained even with a sizable time step increment.