Linear and nonlinear response of a rectangular plate measured with continuous-scan laser doppler vibrometry and 3D-digital image correlation

Dynamic measurement of real structures, such as panels, can be difficult due to their low mass and complicated deformations under large amplitude loading conditions. These conditions bring to light shortcomings of traditional sensors such as accelerometers, strain gauges, displacement transducers, etc. A majority of these sensors require contact with the structure under test which tends to modify the dynamic response of these light structures. In contrast, a few recently developed techniques are capable of measuring the response over a wide measurement field without contacting the structure, which is ideal for these structures. Two techniques are considered here: continuous-scan laser Doppler vibrometry (CSLDV) and high speed three dimensional digital image correlation (3D-DIC). Both techniques can be used to return real-time deformation shapes under certain conditions; however, measurements will be obtained using post processing here. The linear and nonlinear deformations of a clamped flat plate under steady state sinusoidal loading will be measured using both techniques and compared with a finite element model to assess the relative merits of each measurement approach.