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The Steady-State Response of Multidegree-of-Freedom Systems with a Spatially Localized Nonlinearity


Miller, Richard Keith (1976) The Steady-State Response of Multidegree-of-Freedom Systems with a Spatially Localized Nonlinearity. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/M5NW-Z443.


This thesis is concerned with the dynamic response of a General multidegree-of-freedom linear system with a one dimensional nonlinear constraint attached between two points. The nonlinear constraint is assumed to consist of rate-independent conservative and hysteretic nonlinearities and may contain a viscous dissipation element. The dynamic equations for general spatial and temporal load distributions are derived for both continuous and discrete systems. The method of equivalent linearization is used to develop equations which govern the approximate steady-state response to generally distributed loads with harmonic time dependence.

The qualitative response behavior of a class of undamped chainlike structures with a nonlinear terminal constraint is investigated. It is shown that the hardening or softening behavior of every resonance curve is similar and is determined by the properties of the constraint. Also examined are the number and location of resonance curves, the boundedness of the forced response, the loci of response extrema, and other characteristics of the response. Particular consideration is given to the dependence of the response characteristics on the properties of the linear system, the nonlinear constraint, and the load distribution.

Numerical examples of the approximate steady-state response of three structural systems are presented. These examples illustrate the application of the formulation and qualitative theory. It is shown that disconnected response curves and response curves which cross are obtained for base excitation of a uniform shear beam with a cubic spring foundation. Disconnected response curves are also obtained for the steady-state response to a concentrated load of a chainlike structure with a hardening hysteretic constraint. The accuracy of the approximate response curves is investigated.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Applied Mechanics
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Applied Mechanics
Awards:Caltech Distinguished Alumni Award, 2014
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Iwan, Wilfred D.
Group:Caltech Distinguished Alumni Award, Earthquake Engineering Research Laboratory
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 October 1975
Other Numbering System:
Other Numbering System NameOther Numbering System ID
EERL Report75-03
Funding AgencyGrant Number
Record Number:CaltechTHESIS:03052014-104111406
Persistent URL:
Related URLs:
URLURL TypeDescription ItemEERL 75-03, available in CaltechAUTHORS
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8103
Deposited By: Dan Anguka
Deposited On:05 Mar 2014 19:11
Last Modified:23 Aug 2021 22:36

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