Stabilitätsnachweis für komplexe Blech- und Rohrkonstruktionen

Stability proof for complex sheet metal- and tube constructions.

To be competitive on the international market, weight optimization is one of the main objectives in engineering. As Liebherr MCCtec GmbH mainly uses welded sheet metal- and tube constructions, there has to be a large focus on the proof of stability. A huge number of actual rules and regulations in the crane industry are based on nominal stress concepts. On the other hand, finite element method is a widely used method in the design and analysis of cranes. Using the very exact results of this method within these conservative safety concepts leads to uneconomic design. Therefore, creativity in the interpretation of results is required.
In a first step, the theoretical background of stability issues will be covered in this paper. Subsequently the actual situation regarding rules and regulations is discussed. Based on that discussion, the actual approach in Liebherr MCCtec GmbH will be explained. A special attention is given to the issue of dealing with imperfections. By means of two examples the Liebherr MCCtec GmbH approach will be illustrated. Concluding, open issues and ongoing tasks will be examined.