1. Department of Biosystems Engineering, Poznan University of Life Sciences, Wojska Polskiego 50, 60-627 Poznań, Poland
2. Institute of Structural Analysis, Poznan University of Technology, Piotrowo 5, 60-965 Poznań, Poland
3. Institute of Applied Mechanics, Poznan University of Technology, Jana Pawła II 24, 60-965 Poznań, Poland