The flexural behavior of a three-dimensional truss-core sandwich panel may be represented by an equivalent two-dimensional homogeneous but orthotropic thick plate. For the transformation, seven equivalent elastic constants have been derived and these are provided in the paper. In this manner, the 3-D truss-core sandwich panel can be studied using 2-D theoretical and numerical methods. Closed-form solutions of the 2-D orthotropic thick plate are developed in this paper for two different boundary conditions; (a) clamped at all edges and (b) simply-supported at two opposite edges but free at the other two edges. Comparison of response by closed-form solution and finite element analysis showed consistently good agreement.
It is well established that sandwich panels have many potential applications in engineering, aerospace and offshore industries because they promise high strength-to-weight and high stiffness-to-weight ratios. A traditional sandwich panel consists of two facing plates separated by a less-dense material or honeycomb core (Allen, 1969). Recently, however, a novel sandwich form - the truss-core sandwich panel - was considered by the authors (Lok et al., 1999). This form represents a departure from the traditional construction of sandwich panels in terms of fabrication and manufacture. The mass-core sandwich panel is manufacture by joining a number of discrete truss-core units together. The facing plates are an integral part of each unit and these are joined to two sloping truss webs. Depending on the application, the inclination of the truss web can be varied. Thus, the entire unit may be extruded from a continuous production process. Welding or mechanical jointing may be employed to fuse the facing plates of a number of extruded units and from which a wide truss-core sandwich panel is fabricated as shown in Fig. 1. Analysis of the truss-core sandwich panels may be undertaken by using commercially available finite element codes.
