The paper investigates buckling deformation of armchair and zigzag nanotubes with different length-radius ratio(H/R).The results show that the critical strain decreases as the radius increases with certain length-radius ratio nanotubes;length-radius ratio has important effect on the critical strain;for small length-radius ratio

the continuum shell theory is valid

but as length-radius ratio increases and at the radius of less than 0.8 nm

the divergence appears.So macroscopic mechanics frame model...