Affiliations: Los Alamos National Laboratory, ESA-WR, M/S P946 Los
Alamos, NM 87544, USA | Center for Intelligent Materials Systems and
Structures, Mechanical Engineering Department, Virginia Polytechnic Institute
and State University, M/C 0261 Blacksburg, VA 24061, USA
Abstract: Metamodels have been used with success in many areas of engineering
for decades but only recently in the field of structural dynamics. A metamodel
is a fast running surrogate that is typically used to aid an analyst or test
engineer in the fast and efficient exploration of the design space. Response
surface metamodels are used in this work to perform parameter identification of
a simple five degree of freedom system, motivated by their low training
requirements and ease of use. In structural dynamics applications, response
surface metamodels have been utilized in a forward sense, for activities such
as sensitivity analysis or uncertainty quantification. In this study a
polynomial response surface model is developed, relating system parameters to
measurable output features. Once this relationship is established, the response
surface is used in an inverse sense to identify system parameters from measured
output features. A design of experiments is utilized to choose points, representing a
fraction of the full design space of interest, for fitting the response surface
metamodel. Two parameters commonly used to characterize damage in a structural
system, stiffness and damping, are identified. First changes are identified and
located with success in a linear 5DOF system. Then parameter identification is
attempted with a nonlinear 5DOF system and limited success is achieved. This
work will demonstrate that use of response surface metamodels in an inverse
sense shows promise for use in system parameter identification for both linear
and weakly nonlinear systems and that the method has potential for use in
damage identification applications.
Keywords: System parameter identification, response surface metamodel, damping, damage identification
