Acknowledgements

I would like to acknowledge all the following persons:

• Christophe Daux who has put me in contact with Duke University.
• my adviser Dr. John Dolbow, first to have me proposed me this work, to have welcomed me in the US and at Duke University, but also fro his patient with me and th eknoledge in Finite Elements and programming he gave me.
• all the staff of the Department of Civil and Environmental Engineering for his help in the administrative approach
• the International House, especially Lisa Giragosian who indicated me a friendly place to stay.