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Combination of an inverse solution and an ANN for damage identification on high-rise buildings
Quy T. Nguyen,Ramazan Livaoğlu 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.3
Structural health monitoring (SHM) is currently applied to control regularly the health of high-rise buildings which have deteriorated after being subjected to a sudden loading. Damage detection at element levels of a structure consisting of an enormous number of elements becomes the main objective. In this study, the complicated problem is simplified by a two-step solution. Damaged storeys are preliminarily detected before a full damage scenario at an element level is achieved. In Step 1, to overcome the issues related to the huge number of degrees of freedom (DOFs), the full building is simplified to a beam-like system using the Guyan condensation technique. As the natural characteristics of the two lowest modes at the intact and a damaged stage are obtained, the eigenvalue problem based inverse solution is applied to approximately detect damaged storeys. Furthermore, an updating procedure that is proposed in this study effectively enhances the first prediction. In Step 2, an artificial neural network (ANN) model is designed to indicate damaged members on detected storeys using only the first three modal modes. Compared to other approaches applied to detect damages on high-rise buildings, the robustness of the proposed method is that the required number of lowest modal modes is two and three in Step 1 and Step 2 respectively. Furthermore, regardless of the extension of the building in the horizontal direction, only one lateral displacement of each storey is measured to detect damaged storeys in Step 1 and generally detect damaged elements in Step 2. For light and asymmetrical damage scenarios, two more vertical displacements should be considered to obtain accurate element-level detection. However, for all cases, the required number of DOFs is significantly lower than the full system.
Phuoc Quy Phong Nguyen,A.T. Hoang,Abdel Rahman M. S Al-Tawaha 국제이네비해양경제학회 2018 International Journal of e-Navigation and Maritime Vol.9 No.1
Recently, Oil spill incidents from maritime activities and port operation have been causing the serious ocean environment pollution, these problems are said to be the negative effects on the natural environment, social economy, marine species, and human health. Due to the high costs of treating oil spills and oil slick in comparison with a low-income country like Vietnam, many incidents related to the oil spill and oil slick have not been thoroughly processed. Cellulose components from Vietnamese agricultural residues used to produce the absorbent materials are one of the most urgent issues and this is the research object of this work. In this study, two types of structural lengths of cellulose added into PU matrix foam are used to measure how much crude oil, fuel oil, diesel oil and kerosene can be absorbed. The absorbent materials are designed after adding cellulose with 5%, 15%, 25% of mass, respectively. The achieved results show that the oil absorption capacity of PU-cellulose implemented 5% cellulose with 500μm of cellulose structure length and 25% cellulose with 3000μm of cellulose structure length are highest for crude oil. These study results from this work provide a reasonable price for the protection of the marine environment in the strategies of recovery and treatment of oil spill and oil slick on the seawater surface.