1. Department of Mechanical Engineering, Universidade de Brasília, 70.910.900, Brasília, DF, Brazil
2. COPPE/Department of Mechanical Engineering, Universidade Federal do Rio de Janeiro, 21.941.972, Rio de Janeiro, RJ, P. O. Box 68.503, Brazil
3. Centre for Applied Dynamics Research, School of Engineering, University of Aberdeen, AB24 3UE, Aberdeen, UK