A Nondestructive Method to Find the Buckling Capacity for Thin Shells

The presence of imperfections reduces the load carrying capacities of thin cylindrical shells significantly. This reduction depends on the size and the shape of imperfections--the vital information which is difficult and expensive to obtain. All cylinders contain imperfections in one form or another. And thus, the prediction of their buckling capacities is a daunting task which requires the accurate measurement of the imperfections--a difficult and expensive adventure. Due to lack of inexpensive high-fidelity prediction method, thin cylindrical shells are designed by the highly conservative knockdown factor approach. Consequently, the full potential of the thin cylindrical shells is not being exploited. Recently, a nondestructive experimental method has been proposed to obtain the buckling capacity of thin cylindrical shells. In this method, lateral probing is utilized to find the post-buckling equilibrium configuration. The load-displacement profile of the probing carries substantial information, which characterizes the response of the imperfect thin cylindrical shells. This information can be used to obtain the buckling capacities of thin cylinders. In this study, we computationally testify this method and assess its practical feasibility. Local dimple-like imperfect thin cylinders are created, and their buckling capacities are found using two methods: the finite element method, and the newly proposed method using lateral probing. By comparing these two results, the accuracy of the proposed method is evaluated. Moreover, the effect of the location, with respect to the dimple, of probing is also investigated. Concomitantly, the interaction of more than one dimple and the lateral probing is explored to understand the fragility of the proposed method.

View content