Limitations of Equivalent Plate Approach to the Load-Capacity Estimation of Honeycomb Sandwich Panels Under Compression
The subject of the study is the sandwich honeycomb panel under uniform compression. Both facings and the honeycomb core are assumed to be made from aluminium alloy. Ranges of applicability of two equivalent single plate approaches, namely of the method of equivalent rigidity and the method of equivalent length, which may be used to the evaluation of the buckling and ultimate compressive load of the sandwich honeycomb plate are defined. The paper contains results of calculations of buckling and ultimate compressive loads of equivalent plates. Ultimate loads are calculated using the effective width method. Results of these analytical calculations are compared with those obtained by other authors. Simultaneously the theoretical model of the three-layered plate with homogenized orthotropic core is examined. FEA calculations are performed for such a plate with homogeneous core of the homogenized strength characteristics equivalent to that of the honeycomb core. A simplified model of two-layered plate consisting of facings maintained at a constant distance from each other is applied in order to calculate an upper-bound load-capacity of the sandwich panel using the kinematical approach. Conclusions are derived from the comparative analysis of obtained results.