In the consideration of circumferential weld imperfection,a great amount of nonlinear numerical analyses are conducted to investigate the stability of the cylindrical shells when the cylinders are subjected to partial axial compression with the loading subtended angle being less than 10°.

On selection of Fourier series in analysis of geometric imperfections in cylindrical shells;

In second-order elastic analysis of the steel frames, the geometric imperfections of structural system and its individual member should not be neglected.

BSS mechanical analysis of influence from geometric imperfection in prestress-tension stage;

Finite Element Method (FEW is applied to research and analyse thedistribution of stresses in a sample casing under uniform external pressure, whichhas various initial geometric imperfections (ovality and eccentricity).

This paper introduces the functions of the system of structure diagnosing and security assessment for the metal structures of port machinery,emphasizes the principle of diagnosis for the loading capacity of compressed members with geometric imperfection,and illustrates the importance of its application to port.