1. Institute of Continuum Mechanics; Leibniz Universität Hannover; Appelstr. 11 D-30167 Hannover Germany
2. School of Mechanical Sciences; Indian Institute of Technology; Bhubaneswar 751007 India
3. IMT School for Advanced Studies Lucca; Piazza San Francesco 19 55100 Lucca Italy
4. Institute of Structural Mechanics; Bauhaus University of Weimar; 99423 Weimar Germany