allowed for installation of accelerometers on the inside face of the beam. Figure 13 displays a close up view of the connection. For these studies, beam A was tested with the hardware installed, and beam B was the beam alone. Figure 12. Experimental Two-Beam System. Figure 13. Individual Beam Components at Connection. As with the analytical studies, two configurations will be considered, system AB-TR and system AB-TT. The analytical studies showed that exclusion of the rotational connection DOF in the decoupling approaches did not produce error in the estimated FRF of system AB-TR. For this reason, only two connection DOF will be considered on system AB-TR. To obtain drive point connection measurements as well as two internal DOF, four shakers were mounted to Beam A using impedance heads to measure force and acceleration, as shown in Figure 14. The impedance heads were adhered to the middle of the beam at the internal DOF locations and directly to the threaded rod at coupling DOF using a cyanoacrylate adhesive. Figure 14. Shaker Test Setup for Two-Beam System AB-TR. For system AB-TT, an impact hammer and accelerometers were used to obtain drive point measurements at all connection and internal DOF. Figure 15 displays the locations of the accelerometers at each connection. The accelerometers were mounted to the inside face of the beam using a cyanoacrylate adhesive. Drive point measurements were made using an impact hammer on the outer face of the beams, directly across from the accelerometers. Figure 16 displays the six drive point measurement locations made on system AB-TT. Figure 15. Connection DOF Accelerometer Configuration. Figure 16. DOF Locations on System AB-TT. Modal parameter estimation was performed on the measured FRF in LMS Test.Lab. The modal parameters of the first five flexible modes of the individual beams are listed in Table 7. Table 8 lists the modal parameters of the assembled system. 181
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