Slip-buckling analysis of longitudinally delaminated composite columns

• Exact slip-buckling model for columns with partial longitudinal delamination is derived for the first time.
• Exact elastic buckling loads are calculated for various material and geometric parameters.
• Effect of delamination degree on buckling loads is significant.
• The results can be used as a benchmark solution.

This paper presents an efficient mathematical model for studying the slip-buckling behaviour of longitudinally delaminated elastic Reissner’s two-layer composite columns. The present mathematical model is used to evaluate exact critical buckling loads of these columns for the first time. The results prove that the presence of longitudinal delamination can significantly reduce the critical buckling load. The comparison of the results show that if sections outside of full delamination are undelaminated, the results are identical to the ones in the literature. On the other hand, the significant discrepancy may exist when those sections are partially longitudinally delaminated. Moreover, the critical buckling load for shear-stiff column with almost freely sliding longitudinal delamination along the whole column length can be up to approximately 4 times smaller compared to the buckling load of the same but undelaminated column.