*2.1. Modal Equipment*

Modal testing has been performed in conjunction with the mechanical load tests of all specimens to determine modal parameters of the specimen at various states, given in Figure 1. DATS software has been designed by PROSIG for modal analysis. The FFU composite beams have been tested using an impact hammer excitation technique over the frequency range of interest: 0 to 2100 Hz. The data is acquired using the PROSIG P8004 acquisition device for impact hammer modal testing. The modal signals have been measured and recorded using a 2-channel data acquisition for accelerometer and modal hammer connection. The FRFs, which are varied in different ways for healthy and damaged conditions, are then processed using Modal Analysis Suite package to identify natural frequencies and the corresponding mode shapes of the beam specimens.

**Figure 1.** Modal testing and analysis.
