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PROCEEDINGS OF THE ELEVENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING
Edited by: B.H.V. Topping
Noise Reduction Design and Calculation of Super Large Floating Production Storage and Off-loading Systems
D.Q. Yang1, Q. Wang2 and G. Chen2
1School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, P.R. China
D.Q. Yang, Q. Wang, G. Chen, "Noise Reduction Design and Calculation of Super Large Floating Production Storage and Off-loading Systems", in B.H.V. Topping, (Editor), "Proceedings of the Eleventh International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 236, 2007. doi:10.4203/ccp.86.236
Keywords: FPSO, noise control, vibro-acoustics, SEA.
As very important facilities in the offshore oilfields, Floating Production Storage and Offloading System (FPSO) units have been widely employed in recent years. To meet the requirement on the reduction of noise in the cabins and working environment, the noise transmission mechanism and the sound pressure distribution in the FPSO should be predicted during the process of structural design [1,2]. Because of the complication of FPSO, such as the large scale in structural size, the allocations of many kinds of hydrodynamic, electric and mechanic devices, and the wide range of frequency band in noise evaluation (20Hz to 20 KHz), the common acoustic FEM and acoustic BEM are very difficult to employ in the practical engineering design. Furthermore, some of the empirical formulas for noise prediction are outdated as the new generation powerful turbines and HVAC systems are put into use. In most cases, the contractor is responsible for demonstrating measurements that the as-built ship achieves compartment noise specifications. But test verification is available only after sea trials which can not give guidance as to the acoustic design modification during the structural detail design phase of the FPSO.
Fortunately, the special structural features of the FPSO have made the use of statistical energy analysis method practical. The accuracy of the statistical energy analyis (SEA) methods have been demonstrated by many engineering applications [3,4,5]. But for the application with full-ship noise control design of a super large structure, a 300,000 ton FPSO, is still a challenge. To investigate the possibility of noise evaluation by the SEA method in FPSO design, and reveal noise transmission mechanism, a super large FPSO named "Penglai 19-3" was examined in this paper. Noise in typical cabins and the working environment of the superstructure are calculated using the SEA method in all octave bands, 63Hz through to 10 KHz. Having identified the noise transmission path on different decks by thermograms, new noise reduction designs are proposed by adding absorption, insulation materials and viscoelastic damping materials.
The research work showed that the SEA method is capable of predicting noise levels for the large size structures such as the FPSO.
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