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Parameter identification of material constants in a composite shell structureOne of the basic requirements in engineering analysis is the development of a mathematical model describing the system. Frequently comparisons with test data are used as a measurement of the adequacy of the model. An attempt is typically made to update or improve the model to provide a test verified analysis tool. System identification provides a systematic procedure for accomplishing this task. The terms system identification, parameter estimation, and model correlation all refer to techniques that use test information to update or verify mathematical models. The goal of system identification is to improve the correlation of model predictions with measured test data, and produce accurate, predictive models. For nonmetallic structures the modeling task is often difficult due to uncertainties in the elastic constants. A finite element model of the shell was created, which included uncertain orthotropic elastic constants. A modal survey test was then performed on the shell. The resulting modal data, along with the finite element model of the shell, were used in a Bayes estimation algorithm. This permitted the use of covariance matrices to weight the confidence in the initial parameter values as well as confidence in the measured test data. The estimation procedure also employed the concept of successive linearization to obtain an approximate solution to the original nonlinear estimation problem.
Document ID
19930075346
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Martinez, David R.
(Sandia National Labs. Albuquerque, NM, United States)
Carne, Thomas G.
(Sandia National Labs. Albuquerque, NM, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1988
Publication Information
Publication: JPL, Model Determination for Large Space Systems Workshop, Volume 1
Subject Category
Spacecraft Design, Testing And Performance
Accession Number
93N72793
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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