Showing 3 results for Hosseinlou
Farhad Hosseinlou, Alireza Mojtahedi,
Volume 5, Issue 0 (Winter and Spring 2016 2016)
Abstract
Marine industry requires continued development of new technologies in order to produce oil. An essential requirement in design is to be able to compare experimental data from prototype structures with predicted information from a corresponding analytical finite element model. In this study, structural model updating may be defined as the fit of an existing analytical model in the light of measured vibration test. After fitting, the updated model is expected to represent the dynamic behavior of the jacket structure more precisely. In this way, current article presents a direct based updating study of a reduced scale four-story spatial frame jacket structure fabricated and tested at mechanical system and signal processing laboratory. Also, an efficient model updating process is presented with limited modal data, which uses modal data in order to improve the correlation between the experimental and analytical models.
The proposed technique is computationally efficient since it does not require iterations. It updates the mass and stiffness matrix such that they are compatible with the modal data of the observed modes.
Farhad Hosseinlou, Hamid Hokmabady, Alireza Mojtahedi, Samira Mohammadyzadeh,
Volume 11, Issue 0 (Winter and Spring 2019 2019)
Abstract
A simple dynamic model of an offshore jacket platform is developed based on the scaled hydro-elastic model of the jacket to estimate the dynamic response of the system. The finite element model of the platform is updated numerically by using the experimental modal analysis (EMA) results. Dynamic characteristics of the improved simple dynamic model (SPM) and idealized model are specified based on updated model properties. The effects of the experimental test are studied to investigate the dynamic response of a scaled model of an offshore jacket platform through the SPM and idealized models. Seismic response of the jacket platform is studied by using the idealized model under an earthquake acceleration. The effects of marine growth and the corrosion are considered within the calculation process by considering the jacket mass and stiffness variation. The developed SPM and idealized model provide a feasible and effective approach for evaluating the dynamic response of the offshore jacket platform. The results indicate the importance of the experimental studies in validating the numerical results and reducing the uncertainties for the fixed marine structures.
Farhad Hosseinlou, Najmeh Karami, Ehsan Dehghani Firoozabadi, Ehsan Jeddi,
Volume 16, Issue 0 (Summer and Fall 2021 2021)
Abstract
The jacket structure is the key facility for the exploitation of marine resources. Offshore oil platforms located in an earthquake zone need to be analyzed for the structural response. A real offshore structure is always intricate and has to be idealized to diverse degree to fit in to the framework of the mathematical model for dynamic analysis. This work addresses the need for such a facilitated structural computation model. The planned scheme is based on laboratory work for improving the facilitated model. This study describes the scheme in employing the MDC associated with the GA method to create and update the facilitated structural model for analyzing the responses of a jacket platform. The facilitated modelling is first calculated based on MDC method, and then the platform model is refined and improved based on recorded modal features. Considering the presented model, the expense of analysis of jacket offshore structures is considerably reduced without incurring any loss of precision. Therefore, improvement of such approaches would be acutely beneficial to spread out technologies that can be applied for jacket structures with saving of both time and cost.
