Sample questions
How many unknowns are available in Rational Fraction Polynomial (RFP) method as an MDOF method of modal parameter extraction? What happens to the number of unknowns if we use the Global RFP method, instead?
Suggest the best SDOF method to derive the modal parameters from a set of FRFs in each case. Explain the reason briefly:
a. lots of inaccuracy at the resonance frequencies, mode shapes are real.
b. The effect of residue is important, mode shapes are complex.
Having a set of FRF corresponding to a beam as below, answer the questions:
What is the best excitation method (Hammer or Shaker) when we want to get only the plots in the
3^(rd )
column?
Comment on the boundary conditions of the beam according to the FRF characteristics.
Considering the first row of plots, comment on the fidelity of the signals.
Among the points 1,2 and 3 which is the best place to put the exciter?
Among the points 1,2 and 3 which is the best one to place the accelerometer?