1. GRF-CFUM, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal
2. CFUM, University of Minho, Campus of Gualtar, 4700-057 Braga, Portugal
3. SEG-CEMUC Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra, Portugal