USFOS Consultancy

The program is particularly efficient in its ability to model non-linear collapse of structures, requiring fewer elements to model individual structural members than would normally be required by other more general purpose structural and Finite Element analysis programs.

This page describes the capabilities of CREA in the use and support of USFOS. For more detailed information on USFOS visit the SINTEF USFOS home page.

Why translate models?

USFOS is generally used late into the design cycle, for ship impact, extreme wave loading, (push over), fire, blast, etc. There is a great Quality Assurance value to not having to verify a new complex model, as well as a significant saving in cost. Another advantage of translating data is that a cross reference can be generated between the two models, the design model and the USFOS model. This enables the advanced analysis to be reported with direct reference to design analysis. Data translators also have the advantage of being able to carry out model checking as they run, and being able to reliably modify elements. USFOS can model individual structure members with fewer elements than most other packages, therefore, a translator can if necessary, reduce the number elements reliably.

More information on Programming for Analysis.

PCA is used to predict the survival time of a platform in fire, especially significant process fires. Linked to time domain thermal analysis, the time to collapse can be predicted and compared to the required escape times given in the safety case documentation. PCA will give the time to local and global collapse, therefore, it is possible to predict the survival of plant, and the time to failure of plant items which are allowed to collapse. These can then be related to shutdown and blow down times to ensure minimal event escalation and pollution.

USFOS tracks the change in the yield strength and elastic modulus of the steel as the temperature rises, predicts the formation of plastic hinges, and as necessary redistributes load through the structure as the temperature changes. Members can be set to fail and be automatically removed from the analysis. The effects of cooling can be more severe than those of heating, especially on a structure which is significantly damaged due to the fire. The use of a solution scheme such as that used by USFOS is essential to correctly model fire damaged structures, since the heat distribution on the structure has a critical effect on the response. Simple member removal techniques and single element analyses are generally non-conservative.

PCA is used in relation to blast and ship impact analysis to assess the effects on global stability of the entire structure or sub-structures following accidental events. These assessments can include a re-assessment of the ultimate strength in relation to extreme hazard such as wave, wind and earthquake. Note that earthquake response may become significant following severe blast or ship damage.