Experimental study on dynamic responses of aluminum honeycomb sandwich plates subjected to water-entry impact

The pressure characteristics and structural deformation mechanism of aluminum honeycomb sandwich plates (AHSPs) under water-entry impact were investigated through experimental methods. A self-designed drop experimental platform in the water tank was established, and the water-entry impact experiments of AHSPs at different drop heights were carried out. Meanwhile, the deformation of the face sheets was measured by a 3D scanner, and the time history of water impact pressure at different measuring points was monitored. Furthermore, the repeatability of the experiment was verified. On this basis, the water impact load characteristics of AHSPs during the process of water entry were studied and compared with those of other structures in published papers. In addition, the deformation modes and permanent deflection characteristics of AHSPs were analyzed, and the fitting formulas of the permanent deflection of the face sheets and the compression of the core were proposed. Results show that the distribution of the water impact pressure on the front sheet of AHSPs is uneven. However, within the range of drop heights studied, the peak value of the water impact pressure is approximately linear with the drop height. Additionally, compared to the water entry of rigid plates, the peak value of the water impact pressure of AHSPs is smaller. Compared with the mass equivalent aluminum plates, the peak value of the water impact pressure of AHSPs is much smaller, while the pressure duration of AHSPs is longer. The deformation modes of the face sheets of AHSPs at different drop heights are almost the same. Besides, with the increase of the drop height, the permanent deflections of the front and back faces of AHSPs increase approximately in the form of a quadratic parabola with decreasing slope. Suffering from water entry impact loadings, the permanent deflections of the back sheet of AHSPs are smaller than those of the equivalent aluminum plates, indicating that the AHSPs have better impact resistance compared with the equivalent aluminum plates.