Drop Weight Impact Properties of Double Layer Roll Core Sandwich Panels

Abstract

Sandwich panels such as roll core sandwich panel (hereafter, RSP for brevity) and honeycomb core sandwich panel (hereafter, HSP for brevity) are superior in impact absorption under whole surface compression, because of the buffer effect of core. On the other hand, impact properties of sandwich panels under local compression such as drop weight impact are affected by mechanical properties of the plate as the face sheet in addition to the core layer. This paper describes drop weight impact properties of double layer RSP which consists of two core layers and three plates. In order to compare RSP with HSP and build up the experimental database for design of double layer sandwich panel, a series of drop weight tests was carried out by using double layer RSPs and HSPs. From test results, the follows were summarized. The RSP and the HSP have common characteristics: 1) Three peaks of the load appeared in the load-displacement curve. The peak loads were larger in sequence of their appearances. 2) In the load-displacement curve until the last peak of the load, there were load increase regions by deep drawing of the plates and load equilibrium regions similar to plateau region under whole surface compression. Then drop weight impact properties of the RSP are higher than the HSP in terms of 1) the deformation resistances of the load increase regions, 2) the peak loads, 3) the loads of the load equilibrium regions, and 4) the absorption energy until the 2nd peak of the load.