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OnLine Parameter Control of Nonlinear Flexible Structures
https://resolver.caltech.edu/CaltechAUTHORS:20200205141311035
Authors: {'items': [{'id': 'DehghanyarTJ', 'name': {'family': 'Dehghanyar', 'given': 'T. J.'}}, {'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'S. F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}]}
Year: 1987
DOI: 10.1007/9789400935259_9
The use of passive auxiliary mass dampers [1], in which a relatively small auxiliary mass is attached to the primary system by a resilient element, to attenuate the response of oscillating systems has long been a standard method for vibration control. The dynamic vibration neutralizer (DVN), also known as the Frahm damper, is a leading member of the subclass of linear dampers. Its principle of operation relies on the "tuning" of the auxiliary mass so that under steadystate conditions it will generate an opposing force capable of appreciably neutralizing the motion of the primary system. Another member of this group of devices is the Lanchester damper which relies exclusively on mechanical energy dissipation obtained by making the coupling resilient element consist solely of a viscous dashpot.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1wzsvgy938

Identification of nonlinear vibrating structures: Part II  Applications
https://resolver.caltech.edu/CaltechAUTHORS:MASjam87b
Authors: {'items': [{'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'S. F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}, {'id': 'SaudAF', 'name': {'family': 'Saud', 'given': 'A. F.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}]}
Year: 1987
A timedomain procedure for the identification of nonlinear vibrating structures, presented in a companion paper, is applied to a "calibration" problem which incorporates realistic test situations and nonlinear structural characteristics widely encountered in the applied mechanics field. The "data" set is analyzed to develop suitable, approximate nonlinear system representations. Subsequently, a "validation" test is conducted to demonstrate the range of validity of the method under discussion. It is shown that the procedure furnishes a convenient means for constructing reducedorder nonlinear nonparametric mathematical models of reasonably high fidelity in regard to reproducing the response of the test article under dynamic loads that differ from the identification test loads.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/2kq2hfpb63

Identification of nonlinear vibrating structures: Part I  Formulation
https://resolver.caltech.edu/CaltechAUTHORS:MASjam87a
Authors: {'items': [{'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'S. F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}, {'id': 'SaudAF', 'name': {'family': 'Saud', 'given': 'A. F.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}]}
Year: 1987
A selfstarting multistage, timedomain procedure is presented for the identification of nonlinear, multidegreeoffreedom systems undergoing free oscillations or subjected to arbitrary direct force excitations and/or nonuniform support motions. Recursive leastsquares parameter estimation methods combined with nonparametric identification techniques are used to represent, with sufficient accuracy, the identified system in a form that allows the convenient prediction of its transient response under excitations that differ from the test signals. The utility of this procedure is demonstrated in a companion paper.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/14shhx5t91

MeanSquare Response of Hysteretic Oscillators Under Nonstationary Random Excitation
https://resolver.caltech.edu/CaltechAUTHORS:20200205142813929
Authors: {'items': [{'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'S. F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}, {'id': 'SaudAF', 'name': {'family': 'Saud', 'given': 'A. F.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}]}
Year: 1988
DOI: 10.1007/9783642833342_30
A method is introduced for the approximate analysis of the nonstationary random vibration of a broad class of multidegreeoffreedom nonlinear systems, including (but not limited to) hysteretic systems. The approach uses a twostage identification procedure to determine equivalent nonlinear memoryless (nonhysteretic) systems. For purposes of calibration with results obtained by other methods, applications in this paper are limited to the transient meansquare response statistics of a class of timeinvariant bilinear hysteretic oscillators. However, the method is quite general and easily applied to systems incorporating deadspace, impact, frictional sliding, and general experimentallydetermined nonlinearities.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/yjmzjtpy22

A System Identification Approach to the Detection of Changes in Structural Parameters
https://resolver.caltech.edu/CaltechAUTHORS:20200210160215635
Authors: {'items': [{'id': 'AgbabianMS', 'name': {'family': 'Agbabian', 'given': 'M. S.'}}, {'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'S. F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}]}
Year: 1988
DOI: 10.1007/9783663056577_16
Nondestructive evaluation (NDE) methods for the detection of damage in structural systems have been receiving increasing attention in the recent past. Among the promising NDE methods are those based on the analysis of structural dynamic response measurements to identify a suitable mathematical model corresponding to the (changing) state of the physical structure.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ckzt6bva71

An Experimental Study of the Active Control of a Building Model
https://resolver.caltech.edu/CaltechAUTHORS:20120926115230732
Authors: {'items': [{'id': 'NishimuraI', 'name': {'family': 'Nishimura', 'given': 'Isao'}}, {'id': 'AbdelGhaffarAM', 'name': {'family': 'AbdelGhaffar', 'given': 'A. M.'}}, {'id': 'BeckJL', 'name': {'family': 'Beck', 'given': 'J. L.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}, {'id': 'IwanWD', 'name': {'family': 'Iwan', 'given': 'W. D.'}}, {'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'S. F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}]}
Year: 1990
The active control of large structural systems is a subject of growing worldwide interest. One
of the reasons for the increasing attention is the successful application of passive structural
control methods such as baseisolation approaches and damping augmentation techniques.
Research activity in the civil engineering field has been primarily focused on theoretical studies
with few, limited experimental investigations.
This paper reports some of the results of an ongoing analytical and experimental study into the
control of buildinglike structures subjected to nonstationary random excitations such as
earthquakes. The structural model used resembles a 5story building about 2.5 meters high.
The building model was subjected to a variety of directforce excitations. The control algorithm
used employes an adaptive structural member at a predetermined location in the model in
order to attenuate the structural response relative to the moving building foundation. An electromagnetic
actuator is used to generate the required control forces in the "smart" member.
Among the key features of the algorithm under discussion are:
1. Only one active controller is required to attenuate the vibration response contributed by
the first three modes; the damping factor is increased from virtually zero to about 20%.
2. Only two sensors are needed for this algorithm; this leads to simpler instrumentation
and a more robust system.
3. Due to the optimization procedure used to select the controller location, a significant
amount of damping augmentation is obtained from a relatively small amount of control
energy.
4. The whole design procedure was demonstrated, especially attention was paid to time
lag problem of the active controller and the stability of the system was discussed.
As part of the design phase of this study, a system identification procedure was used to develop
a suitable reducedorder mathematical model. The results of a simulation study using this identified
model are compared to experimental measurements. Problems encountered in the experimental
phase of the study are reported and discussed. It is shown that (1) the algorithm under
discussion is capable of reliably controlling the motion of the test structure under arbitrary dynamic
environments, and (2) the features of the algorithm makes it a promising candidate for
application to large civil structures.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/bf7jmtkc07

An Experimental Study of the Active Control of a Building Model
https://resolver.caltech.edu/CaltechAUTHORS:20120830153547717
Authors: {'items': [{'id': 'NishimuraI', 'name': {'family': 'Nishimura', 'given': 'Isao'}}, {'id': 'AbdelGhaffarAM', 'name': {'family': 'AbdelGhaffar', 'given': 'A. M.'}}, {'id': 'MasriSF', 'name': {'family': 'Masri', 'given': 'Sami F.'}}, {'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'R. K.'}}, {'id': 'BeckJL', 'name': {'family': 'Beck', 'given': 'J. L.'}}, {'id': 'CaugheyTK', 'name': {'family': 'Caughey', 'given': 'T. K.'}}, {'id': 'IwanWD', 'name': {'family': 'Iwan', 'given': 'W. D.'}}]}
Year: 1992
DOI: 10.1177/1045389X9200300108
This paper reports some of the results of an ongoing analytical and ex perimental study into the control of buildinglike structures subjected to nonstationary ran dom excitations such as earthquakes. The structural model used resembles a 5story build ing about 2.5 meters high. The building model was subjected to a variety of directforce excitations. The control algorithm used employs an adaptive structural member at a prede termined location in the model in order to attenuate the structural response relative to the moving building foundation. An electromagnetic actuator is used to generate the required control faces in the "smart" member. Among the key features of the algorithm under dis cussion are:
1. Only one active controller is required to attenuate the vibration response contributed by the first three modes; the damping factor is increased from virtually zero to about 20%.
2. Only two sensors are needed for this algorithm; this leads to simpler instrumentation and a more robust system.
3. Due to the optimization procedure used to select the controller location, a significant amount of damping augmentation is obtained from a relatively small amount of control energy.
4. The whole design procedure was demonstrated; special attention was paid to the time lag problem of the active controller and the stability of the system was discussed.
As part of the design phase of this study, a system identification procedure was used to develop a suitable reducedorder mathematical model. The results of a simulation study J. of IN TELL. MATER. SYST. AND STRUCT., Yol. 3 January 1992 1045389X/92/01 013432 $6.00/0 © 1992 Technomic Publishmg Co., Inc. using this identified model are compared to experimental measurements. Problems en countered in the experimental phase of the study are reported and discussed. It is shown that 1) the algorithm under discussion is capable of reliably controlling the motion of the test structure under arbitrary dynamic environments, and 2) the features of the algorithm make it a promising candidate for application to large civil structures.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/70vy4gcd70

The Steadystate response of multidegreeoffreedom systems with a spatially localized nonlinearity
https://resolver.caltech.edu/CaltechEERL:1975.EERL7503
Authors: {'items': [{'id': 'MillerRichardKeith', 'name': {'family': 'Miller', 'given': 'Richard Keith'}}]}
Year: 2001
This thesis is concerned with the dynamic response of a general multidegreeoffreedom linear system with a one dimensional nonlinear constraint attached between two points. The nonlinear constraint is assumed to consist of rateindependent 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 steadystate 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 steadystate 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 steadystate response to a concentrated load of a chainlike structure with a hardening hysteretic constraint. The accuracy of the approximate response curves is investigated.
https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/kq2nw70j55