CE591 Modeling and Identification in Structural Dynamics
Spring 2004
Instructor Name Hilmi Lus
Office M 3175
Office Hours MT 11:00-12:00
Tel. (212) 359 6594
e-mail hilmilus@boun.edu.tr
home page http://www.ce.boun.edu.tr/eng/people/faculty/lus/
Course Data Hours
Location
Course Description (2002 Catalog)
CE591 Modeling and Identification in Structural Dynamics
(3+0+0)3

Basic Formulations in Structural Dynamics. Time and Frequency Domain Models. Identification Problem. Output and Equation Error Approaches. Least Squares. Nonlinear Least Squares. State Space Formulations. Subspace Methods.  Physical Parameter Estimation.
Reference Books

Ewins, D. J., "Modal Testing: Theory and Practice", Research Studies Press, 624.176-EW5M.
Ljung, L., "System Identification: Theory for the User", Prentice Hall, QA402 .L59 1987, QA402 .L59 1999.
Juang, J. -N., "Applied System Identification", Prentice Hall, TA168 .J83 1994

Computer Usage
The students are expected to have full command of MATLAB or any other programming language suitable for the projects assigned.
Class Policies
The students are graded based on their performances in the assigned projects and homeworks. There is no in class exam.
Course Outline
I.The Forward Problem

Analysis of a Single Degree of Freedom (SDOF) system. Time domain and frequency domain solutions. Transfer functions. Spectral analysis. Multi DOF systems. Eigenvalues and Eigenvectors. Classical and Non-Classical damping. Nonlinear equations of motion.
II.Basic Approaches in System Identification

Problem statement and brief historical review.  Equation error formulation. Direct identification of coefficient matrices in the second order formulation. Least squares solutions. Moore-Penrose pseudo-inverse. Singular value decomposition. Integration techniques. Effects of noise on identified parameters. Output error problem. Nonlinear optimization problem in modal coordinates.
III.Minimal Realization Theory

State space formulation. Discrete time formulation. Complex modal parameters. Markov parameters. Realization theory. Eigensystem Realization Algorithm (ERA) and its variants. Observer formulation. Kalman filter. OKID algorithm. Other subspace techniques.
IV.Estimating Physical Parameters via Identified State Space Models

Collocation. Estimating normal modal parameters from identified complex modal parameters. Full order models. Sensor-actuator requirements. Reduced order models. Relations between reduced and full order models. Identifiability.
V.Estimating Physical Parameters via Identified State Space Models
Observations and definitions from 1D experiments and discussions. Applications of 1D theory to beams. Discussion of yielding in 2D and 3D. Tresca, Mohr-Coulomb, and Mises yield criterion. Applications to 2D problems. Flow rules.
VI.Time Dependent Inelastic Materials
Observations and definitions from 1D. Mechanical models used in linear viscoelasticity. Maxwell, Kelvin, standard solid materials. Creep and Relaxation. Superposition Integrals. Solution by Laplace transform. Shear and 3D responses. Vibration response.