Buckling loads under combined longitudinal and transverse direct stress of flat sandwich panels. (Isotropic face plates and orthotropic cores of zero flexural stiffness@ all edges simply-supported.)
The elastic buckling loads are presented graphically in terms of the overall dimensions of the panel and its flexural and through-the-thickness shear stiffnesses. The loadings covered are either uniaxial in-plane compression alone or with a transverse in-plane tensile or compressive load. The data are applicable to sandwich panels in which the core exhibits negligibly low flexural stiffness (and compressive or tensile stiffness) but contributes significantly to the through-the-thickness shear stiffness@ for example cellular cores such as honeycombs@ end grain balsa@ etc. The panel length to width ratios covered are from 0.2 to 2.5 (approximately) and infinitely long panels. See ESDU 68029 for the background to the theory and for calculations of sandwich panel stiffnesses. See ESDU 81047 and ESDUpac A8147 or ESDU 94005 and ESDUpac A9405 for a computer program for calculation of buckling load.