Geology Reference
In-Depth Information
Chapter 14
Health Assessment of
Engineering Structures
Using Graphical Models
Abbas Moustafa
Minia University, Egypt
Sankaran Mahadevan
Vanderbilt University, USA
ABSTRACT
A hybrid qualitative-quantitative health assessment of structures using the bond graph theory is presented
in this chapter. Bond graph (BG) is an energy-based graphical-modeling tool for physical dynamic
systems, actuators, and sensors. BG provides domain-independent framework for modeling dynamic
systems with interacting components from multiple domains. Discrete structures are modeled using one-
to-one bond graph elements, while continuous structures are modeled using finite-mode bond graphs.
BG facilitates the construction of temporal causal graph (TCG) that links the system response to the
damaged component or faulty sensor. TCG provides qualitative damage isolation, which is not possible
using most existing system identification techniques. This leads to rapid isolation of damage and sig-
nificant reduction in computations. Quantitative identification of damage size is performed by analyzing
the substructure containing the damaged component, using the nonlinear least-squares optimization
technique, thus reducing the computations. The health assessment algorithm developed in this chapter
combines the Generic Modeling Environment (GME), the Fault Adaptive Control Technology (FACT)
software, and Matlab Simulink®. Numerical illustrations on BG modeling of a hydraulic actuator and
system identification of a fifteen-story shear building and a high-rise structure under earthquake loads
are provided.
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