Wind loading for Fitness for Service Assessment

Thanks to previous work performed by DOCAN, an effective repair plan had been arranged involving removing and replacing large sections of damaged vessel wall. This means during repair there would be sections of decreased strength while material was missing.

It was considered that a strong unexpected gust may consequently endanger the success of the repair operation. Detailed wind loading assessment was required to consider the attachments to the vessel required for the repairs and the various ways the vessel would be weakened mid repair.

Maple mathematical software was utilized to produce formalized hand calculations for the wind loading pressures to be endured by the vessel, and the overturning moments that they will produce, as well as determining the thermal expansion of the vessel.

This provided verification of the results of the PV Elite model and allowed additional customization to consider all parameters and attachments that contribute to the wind loading effects. These Maple calculations give verification that the FEA models are constructed properly and giving sensible results that the client can understand and trust.

Various wind sensitivity studies were performed using MSC Marc, to determine the maximum cut-out size that can be removed at any one time and the most effective cut-out sequence to preserve the strength of the remaining vessel allowing the repairs to be contained within the allocated time for the client’s scheduled maintenance.