Detecting structural damage using frequency response functions

The optimization of frequency response functions (FRF) is investigated to diagnose damage using minimum number of sensors. All the information contained in the FRF function is used along with the analytical model, model connectivity, and bounds on the structural stiffness values. The technique requires a lot of computation which may restrict it to small models. Also, FRFs may not be exactly repeatable due to variations in temperature which changes the elastic modulus and causes boundary conditions to change.