Executive Summary : | The load-carrying capacity of thin shells depends on the underlying imperfections. Thus, one requires an a priori knowledge about the underlying imperfections to make accurate failure predictions. However, measuring all the underlying imperfections is difficult, expensive, and time-consuming, thus making predictions of a shells' capacity nontrivial, if not impossible. As a result, thin shells are designed extremely conservatively using the knockdown factor approach that accommodates the uncertainties associated with underlying imperfections. Nevertheless, the quest for inexpensive high-fidelity estimates of the load-carrying capacity of thin shells has been continued for a long time. Recent studies show that the methods based on the stability landscape, which is obtained by the lateral probing of compressed thin shells, have the potential for capacity predictions without measuring the underline imperfections. However, these methods are still in a nascent stage, and many outstanding issues have to be resolved, namely, the role of probing location, and identification of the probing location, which yields accurate prediction. This project proposes to develop a high-fidelity method for the capacity prediction of thin shells without the knowledge of underlying imperfections. The proposed method will be built upon the recent advances in thin shells theory by resolving the issues of the role of probing locations and the identification of the probing location. First, a technique will be developed, based on computational analyses, for the identification of the location of probing that yields an accurate prediction. Second, experimental and computation verification will be done to evaluate the efficacy of the identification technique. The final product of the project will be a set of steps if follows, yields an accurate capacity prediction of thin shells without the knowledge of the underlying imperfections. Further, the capacity of thin shells will be predicted both experimentally and computationally following the proposed steps to verify the efficiency. The outcome of the proposed work will have far-reaching effects: improving the reliability of thin-walled structures, increasing their payload capabilities, and identifying sensible design rules for the safe fabrication of modern structures. |