MSc Thesis Title: Οptimization of dynamic response of liquefied natural gas tanks

Thursday 28 March 2019, at:13:00, Venue: Hall K2.A3

Examination Committee

• Associate Professor Yannis TSompanakis (advisor)
• Associate Professor Tryfon Daras
• Associate Professor Nikolaos Lagaros

Abstract:

This post-graduate diploma thesis focuses on the optimization of the dynamic response of liquefied natural gas (LNG) tanks. The study investigates the seismic response of particular types of LNG tanks, using advanced computational methods. Specifically, the possibility of improving the dynamic response of the tanks, using effective seismic isolation systems at the foundation level, constitutes one of the most important aspects of this study.

The aforementioned goals are achieved through the application of finite element software for the analysis of the complex dynamic interaction (tank-liquid- interaction). Furthermore, an efficient methodology for improving the seismic response of tanks through optimization of critical design parameters of the isolators has been developed. This has been achieved by developing a code that is applicable to real data and is able to lead to the implementation of optimal seismic protection measures, more efficient techno-economic design so that to reduce the probability of failure of the superstructure. Specifically, codes were developed using MATLAB so as to implement optimization methodology using Cuckoo Search algorithm, while the results were used as input data in the finite element software in order to carry out the parametric study of the dynamic response of the tanks.

The outline of the study is briefly described: Firstly, the seismic design of LNG  tanks is described. Subsequently, the theoretical background which has been implemented for the simulation of the dynamic response of isolated tanks is presented. Then, the optimization formulation is configured, which includes the design variables as well as objective and constraints functions. In addition, the optimization algorithm and the developed MATLAB codes are presented. Then, the examined tanks are simulated and analyzed using finite element software SAP2000. Finally, a detailed parametric analysis is conducted, the numerical results are presented and compared to results derived from relevant studies, and the conclusions drawn are provided.