The influence of non-linear material behaviour on strong vibration effects due to explosion loading

In order to investigate the effects of introducing non-linear material behaviour on the dynamic response of a topsides structure to explosion, a series of analyses has been carried out using a geometrically detailed finite element model. The work reported in this document builds upon that carried out during Phase 2 of the Strong VibrationWorking Group JIP, in which purely elastic models were used in predicting the strong vibration demands placed upon Safety Critical Elements. A series of nine analyses was undertaken to determine the influence of non-linear material modelling on secondary response spectra, generated at discrete locations throughout the topsides structure. Previously, direct scaling of peak spectral accelerations obtained by linear analysis had been used to obtain results for explosions of differing peak overpressure. This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of the copyright owner. ii ACKNOWLEDGEMENTS EQE International Limited wish to acknowledge the Health and Safety Executive for their funding of the research into the influence of non-linear material behaviour on strong vibration effects reported in this document. EQE International Limited also wish to acknowledge the Strong Vibration Working Group and TotalFinaElf Exploration (UK) plc, for their funding of the substantial body of research into the Strong Vibration hazard that precedes this non-linear analysis and upon which this non-linear analysis is based.