New connections for sandwich towers of wind energy converters: Fid-Bau Portal

New connections for sandwich towers of wind energy converters

Schaumann, Peter / Keindorf, Christian

A new kind of tube-in-tube connection is presented which can be used to connect sandwich tower sections with steel sections without any bolts or ring flanges. Therefore, the upper steel section is positioned between the inner and outer steel face of the sandwich section. Thus, forces and moments can be transferred with shear stresses along an overlap length. The sandwich joint works as a double shear connection and can compensate vertical misalignments and imperfections. The ultimate limit state can be increased with prefabricated shear keys along the overlap length. In combination with the advantages of the new sandwich sections and the use of high-strength steels the presented tower concept could be a new alternative solution for wind energy converters. A new tower concept with a sandwich section was analyzed with regard to shell stability. The sandwich shell consisted of an inner and outer steel face, which were bonded adhesively to different core materials between them. For a combination with upper steel section a new kind of tube-in-tube connection was presented. Therefore the upper steel section is positioned between the inner and outer steel face of the sandwich section. Thus, the sandwich joint works as a double shear connection and can compensate vertical misalignments and imperfections. Furthermore, no ring flanges and no bolts are necessary to transfer the forces and moments between the sections. The ultimate limit state of the sandwich joint depends on the compressive and bonding strength of the core material and can be increased with shear keys along the overlapped length.