1 Unit for Strength of Materials and Structural Analysis, Institute of Basic Sciences in Engineering Science, Innsbruck University, Technikerstr. 13, A-6020 Innsbruck, Austria. Matthias.Neuner@uibk.ac.at.
2 Unit for Strength of Materials and Structural Analysis, Institute of Basic Sciences in Engineering Science, Innsbruck University, Technikerstr. 13, A-6020 Innsbruck, Austria. Peter.Gamnitzer@uibk.ac.at.
3 Unit for Strength of Materials and Structural Analysis, Institute of Basic Sciences in Engineering Science, Innsbruck University, Technikerstr. 13, A-6020 Innsbruck, Austria. Guenter.Hofstetter@uibk.ac.at.