Packages for the transport of radioactive material are generally equipped with particular components for crane operations and supporting the package during transport. As an example of such components the bolted trunnion system of heavy packages are analysed in this paper.
According to the German guideline BAM-GGR 012 created by the BAM Federal Institute for Materials Research and Testing for analysis and assessment of bolted lid and trunnion systems, the finite element (FE) method is to be used preferably in the analysis of such kind of structures to obtain more accurate and detailed information about their stressing. The FE model of a trunnion system should include the trunnion itself, the bolts and an appropriate part of the packaging wall with necessary contact conditions on all interfaces between these components. The use of solid finite elements, which is generally recommended in the BAM-GGR 012 guideline, leads to local stress and strain fields as a result of the calculation. The modelling strategy, e.g. the way of modelling interaction between the components of the trunnion system, has an essential impact on these local values.
The effect of different assumptions in a FE model is demonstrated in this paper using the calculation results for a reference trunnion system. The approaches for preparation and interpretation of results in connection with local or nominal assessment criteria are discussed as well.