Buckling of imperfect thin shell tank which is subjected to uniform axial compression is analyzed. The effect of internal pressure on the stability of a shell tank filled with a homogeneous-heterogeneous liquid was considered. Investigation of the liquid nature effect on reduction of the shell buckling load is performed by using the finite elements method. Calculating results in terms of analytical formula give a good agreement with the numerical results given by Abaqus when using actual measurements. The obtained results show the influence of the physical characteristics of liquid especially in the case of heterogeneous liquid. The study of combination between compression load, lateral pressure and the mechanical properties of liquid filling the tank is recommended for dimensioning the shell tanks to avoid the buckling phenomenon. Manuscript profile