Experimental Investigation of Dynamic Response and Deformation of Aluminium Honeycomb Sandwich Panels Subjected to Underwater Impulsive Loads

Abstract

The response of aluminium sandwich panels with three thicknesses’ core subjected to different underwater loading levels has been studied in the fluid-structure interaction (FSI) experiments. The transient response of the panels is measured using a three-dimensional (3D) Digital Image Correlation (DIC) system, along with high-speed photography. The full-field shape and displacement profiles of dry face sheets were recorded in real time compared with those of monolithic plate. The out-of-plane deflection and in-plane strain were quantified and analyzed. Three typical deformation modes of sandwich panel were identified. The results show that the core structure is crushed resulting in an initial large circular shape of deformation in the center area of panels. From this moment on, the panel is starting to act as a free vibration beam with initial velocities. The deformation modes consisted of homogeneous large deformation for both face sheets, obvious deformation border on wet face sheet, core node imprinting, remarkable wrinkled skin of deformation border, and a partial delamination and partial tear failure of the dry face. The blast-resistance of sandwich panel can be highly efficiently improved by increasing the thickness of core structure.

Centrosymmetric 3D Deformation Measurement using Grid Method with a Single-Camera

“…The bulging parts were increasingly closer to the center, and the center pits began to plump up; the out-of-plane displacement reached a peak at 952 μs. This phenomenon was similar to that reported in [37], in which a pair of high-speed cameras was used.…”

“…Compared with the morphological results measured by 3D SMM, the results obtained through the proposed method have a 2 % error. Sample panel 3D deformation measurement in a simulated underwater explosion experiment confirmed the effectiveness of this approach in a high-speed impact experiment compared with experimental results in literature [19,37]. The centerline deformation processes of the sample panel were identical.…”

“…6(a)) is similar to that used by Espinosa et al [19] which uses a laboratory setting for underwater explosive loading conditions. In the FSI setup, a water chamber made of a steel tube was incorporated into a gas gun apparatus [37]. The specimen panel and a 22 mm thick piston were installed at the rear and front ends.…”

“…The specimen panel and a 22 mm thick piston were installed at the rear and front ends. Exponentially decaying pressure was produced by impacting the piston with a 5 mm thick flyer plate launched by a gas gun [37]. More details on the experimental principles and the impact process of pulse loading can be found in the literature [19,37].…”

“…Exponentially decaying pressure was produced by impacting the piston with a 5 mm thick flyer plate launched by a gas gun [37]. More details on the experimental principles and the impact process of pulse loading can be found in the literature [19,37]. The experiment used an aluminum plate as the sample panel and a single-camera and grid to measure the dynamic 3D deformation under impulsive loading.…”