Ikke-Lineær Elementanalyse av Pipe-Support Utsatt For Ulykkeslast

Abstract

Offshore structures may be some of the most complex structures and are subjected to va- rious and complex loads. Design of such structures is therefore off extreme importance to ensure the safety of workers and the environment. This master thesis will reaserch the case of blast loads and how to design pipe-support accordingly with the following reaserch question «How will different deisgn parameters effect the integrity of pipe-support structures subjected to blast loads».

To investigate this topic we have completed non-linear finite element analysis with use of ANSYS. The case we have chose for this analysis is a pipe-support subjected to load from the pipe system reacting to the blast. The direct blast load pressure has been neglected for the pipe-support structure itself, since it has little effect on the overall integrity. The design parameters selected is local slenderness of column (B/t), thickness of profile wall (t), angle of load (θ) and length of column (L). Our findings suggest that local slenderness will impact the structural integrity the most and is the leading factor. Low local slenderness gives higher capabilities for plastic behaviour before fracture. For thickness and length the results show little contribution to the factor, altough this may be caused by differences in simulations and other uncertanties. Load angle show to have an effect where it is linear from 0 − 15◦ and constant from 15 − 45◦. Furthermore it is shown that it is possible to generate factors that allow for 5%, 7.5% and 10% plastic strain. This is made possible due to the fact that non-linear analysis allow for plastic behaviour of the structure and gives a more realistic replication. For further work it is recommended to do dynamic analysis to establish greater realistic simulations.