Abstract: There exist many theoretical models for predicting the critical buckling values of sandwich structures under compression/bending loads. In these models, few researcher has taken into account the effect of transverse shear on the face layers during buckling. In addition, the characteristics of the existing buckling formulas are as follows: classic formulas are simple in form but have low prediction accuracy and a narrow range of applications, and thus not convenient for users; some models s have high accuracy but complex forms, and are not convenient for direct engineering application. In this paper, we establish a new theoretical model for solving the problem of buckling based on the elastic theory. In the new model, the transverse shear effect of the face layer is taken into account for the first time, and the influence of shear effect on the buckling load is evaluated. By simplifying the exact solutions in different buckling wavelength ranges, we establish the approximate solution models, and then the accuracy and applicability of these approximate solutions are determined. Finally, a new failure criterion for determining the buckling of sandwich structure is established. The new criterion leads to better prediction precision and is concise, and is thus easy to be applied in engineering.

Key words: sandwich structure, buckling, wrinkling, theoretical solution, transverse shear