Biography
Biography: Robert Kielb
Abstract
If not designed properly, the blade and vanes of rotating machines, such as turbines, are susceptible to high cycle fatigue failure due to high vibratory response. Th e well-known Campbell diagram is used to help maintain a separation between excitation and natural frequencies. However, the plethora of excitation and natural frequencies can make avoiding resonances diffi cult, or practically impossible. In these cases, forced response design analyses can be used to predict the resonant response.Th is has been done for over 20 years, but the accuracy and probabilistic nature of the problem still have many unanswered questions. Th ere are unknowns in the forcing function, damping and mistuned response. Th is is especially the case for the blades and vanes of embedded compressor stages. Th is paper summarizes the results of an exhaustive computational and experimental study of compressor blade resonant response. Th e focus is on the rotor forced response in a 3.5 stage compressor
rig at Purdue University. Th e infl uence of refl ecting boundary conditions on the blade modal force is studied. Th e computational aerodynamic and hysteretic damping are compared with measured values and the mistuned response with multiple models are compared with measurements.