The Inverse Finite Element Method: Sensitivity to Measurement Setup
Date
2005-03
Authors
Maree, Abraham Jacobus
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
In the inverse finite element method (iFEM), given a finite element model of a structure
and imperfect displacement measurements, the external loads acting on the structure
can be assessed. The basic idea behind iFEM is the optimization of a quadratic cost
function of the difference between the measured and estimated values, with a high cost
corresponding to a high precision of the measurements.
In the present research it is firstly shown how the iFEM theory was broadened to
accommodate for strain measurements through the construction of cost matrices to express
the cost associated with the estimation of the response.
The main focus of the research falls however on the influence that the measurement
set-up has on the quality of the iFEM estimates. Only a limited number of measurements
may be available, therefore it is essential to plan the measurement set-up carefully to
obtain the highest quality of estimates. The number of measurements and the precision
required to obtain a realistic result from an iFEM analysis is also a factor which plays a
role and varies for different types of measurements. A numerical method for systematic
sensitivity study of the measurements set-up without involving the actual measurement
data, is presented.
Two examples consisting of structures with both displacement measurements and
strain measurements being taken, are presented. It illustrates how the sensitivity study
method can be used to plan a more effective measurement set-up.
Description
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2005.
Keywords
Theses -- Civil engineering, Dissertations -- Civil engineering