Which range is representative of the material

1
Frequency sweep method Continuous sinusoidal
wave
Very stiff materials (Gvh0.33-1.5GPa)
At low frequencies signal is very weak -
difficult to read
At high frequencies signal is clear
Several phase shifts in the whole range.
Which range is representative of the material?
2

• round robin feedback by email to Dr.Yamashita
• frequency domain vs time domain high frequency
  readings valid?
• platen effects?
• alternative systems shear plates, Fioravante
  BE system, 2 receivers?
• correspondence of transmitted wave with input
  signal self monitoring
• elements