1. Key Laboratory of Coastal Disaster and Defence (Ministry of Education), Hohai University, Nanjing, P.R. China;
2. Center for Numerical Simulation Software in Engineering & Sciences, College of Mechanics and Materials, Hohai University, Nanjing, P.R. China;
3. State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics & Astronautics, Nanjing, P.R. China;
4. Department of Mathematics, CEMAT, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal