Experimental Modal Analysis

Sample preparation

For both the cases, delaminations have been introduced in two different layers of the 4-ply laminates. The laminates with delaminations in the middle layer (i.e. II interface) are designated as Type A and those with delamination in the offset layer (i.e. I interface as shown in Figure 37.2) are designated as Type B. The experiments are conducted on these composite plates in fixed-free boundary condition (more precisely C-F-F-F). Dynamic excitation is given at the center of the plate by an electro-dynamic shaker. Laminated composite plates used in experimental modal analysis are detailed in Table 37.2.

Table 37.2 Laminated composite plates used in experimental modal analysis

The experiments are carried out on Polytec Scanning (PSV) Vibrometer in 3-D scan mode. The excitation details are provided in Table 37.3

Table 37.3 Detalis of the excitation signal used in 3-D scan mode