86 P. Castellini et al. Fig. 8.3 Mode shapes of the tail cone obtained by modal analysis (step scanning method); tail cone top view 8.2.3 Continuous Scanning LDV Method In this paragraph the CSLDV method is illustrated. This experiment was designed so as to perform a straight-line scan along the tail cone, as shown by a red line in Fig. 8.1. Hence, the scanning laser was then used in continuous mode rather than stepped one. Having obtained the natural frequencies a multi-tonal excitation waveform could be built using the natural frequencies, as reported in Table 8.2. A straight-line was scanned along the tail cone across some of the measurement points used for the step scanning measurements. Four sets of measurements were produced on the tail cone using three different scan rates for scanning the line and these are reported in Table 8.3. Seven ODSs, as reported in Fig. 8.7, were reconstructed from the CSLDV time histories; amplitude and measurement positions were scaled between 1 and 1 to simplify the comparison. 8.2.4 Mode Matching Analysis Results from processing the CSLDV data measured on the Linx Tail cone using the mode matching approach are discussed in this paragraph.
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