Stiffness and Damping Identification from Full Field Measurements on Vibrating Plates

Abstract

The paper presents an experimental application of a method leading to the identification of the elastic and damping material properties of isotropic vibrating plates. The theory assumes that the searched parameters can be extracted from curvature and deflection fields measured on the whole surface of the plate at two particular instants of the vibrating motion. The experimental application consists in an original excitation fixture, a particular adaptation of an optical full-field measurement technique, a data preprocessing giving the curvature and deflection fields and finally in the identification process using the Virtual Fields Method (VFM). The principle of the deflectometry technique used for the measurements is presented. First results of identification on an acrylic plate are presented and compared to reference values. Results are discussed and improvements of the method are proposed.

Time-resolved full-field imaging of ultrasonic Lamb waves using deflectometry

“…The damping parameter is denoted η in Table 2. It corresponds to the parameter m j in equation (14)(15)(16)(17)(18)(19)(20)(21)(22) from the theory reference of ANSYS [28]. From the numerical results, the data have been retrieved in the same region as the deflectometry results.…”

“…The method adopted here is the grid method in deflectometry [13,[17][18][19]. It provides spatially and temporally resolved surface slope maps by tracking the reflection of a regular grid pattern on the bent sample.…”

Full-Field Strain Measurement and Identification of Composites Moduli at High Strain Rate with the Virtual Fields Method

“…This approach has already been successfully applied in vibration to identify damping properties of thin plates [41][42][43][44][45] but never to a high strain rate loading cases.…”

Full-field strain measurements at high rate on notched composites tested with a tensile Hopkinson bar

“…It has to be underlined that this use of the VFM using only the inertial effects as information source has never been made until now for such a high speed dynamic case. It has only so far been used for identification of damping parameters of vibrating plates [6]. So, although the results have to be improved, this approach remains original and quite promising.…”