Reconciliation of Finite Element Model of a Simplified Model of Oil Rig Platform Structure

Abstract

Vibration effects on the complex structures such as oil rig platforms are extremely difficult to investigate due to operation conditions and harsh environments. The information of the structural vibration behaviour of such structure are extremely significant at the design stage, in order to overcome failures and disaster especially during the structure’s operation. In this paper, the vibration responses of the simplified oil and gas platform structure is investigated using finite element analysis (FEA). The simplified model oil and gas platform structure are modelled using two type of elements namely shell element and beam element and the feasibility between the two modelled are evaluated. The first ten elastic modes in terms of natural frequencies and mode shapes of the finite element (FE) model is validated with experimental modal analysis (EMA) counterparts to quantify accuracy of developed FE model of the structure. The result shows that FEA-SHELL Model was providing the greater accuracy compared to FEA-Beam Model despite burdened with modelling uncertainties. Nevertheless, reconciliation scheme via FE model updating was introduced for improving the structure’s modelling uncertainties. In conclusion, despite the initial FEA-SHELL Model associated with modelling uncertainties, the model can still be considered as the best choice to predict the dynamic responses of the simplified oil and gas platform structure with the aid of FE model updating method.