Project's information

Project's title Fatigue Analysis and Fatigue life Evaluation of Offshore Structures accounting the undeterminate factors
Research hosting institution Institute of Mechanics
Project leader’s name Dao Nhu Mai
Project duration 01/01/2010 - 01/01/2011
Project’s budget 300.000.000,0 VND
Classify Fair
Main results

Theoretical results:
+ Numerical simulation of linear random waves. Wave load calculation module was completed. Results of the program is serveved as input for further analysis.
+ Modified FE Models: Euler Beam-Column Element accouting effects of axial force; Elasto-Plastic Harderning Foundation model describing the iteraction between soil and structures. The element matrix has been establiched for the models in incremental form.
+ Newmark Method has been used in non linear dynamic analysis. Monte Carlo Technique was applied to evaluate the statistic characteristic of stress range for the hot spot at welded joints in main pipes.
+ Implementation of the Ang A. H.-S Reability Based Fatigue analysis Procedure. A program has been constructed.
Applied results:
Three structures at different sea depth have been choisen for testing program.
+ Collected wave data in Bạch Hổ sea were used for calculation of wave loads acting on structures.
+ Suitable FE model were used to modelling the nonlinearilies in structure
+ Reability Based Fatigue analysis Procedure was implemented using for different simulation of the random wave.
+ Received results have been compared with the results received using the determinated approach.
The results shows that random simulation give fatigue life heigher than the determanited approach.
Novelty and actuality and scientific meaningfulness of the results

Reability Based Fatigue analysis Procedure has been implemented for offshore structures using the numerical simulation of random waves and the FE modified elements for modelling nonlinearitíe of structures.
Products of the project

Scientific papers in referred journals (list):

  • Dao Nhu Mai, Le Thi Viet Anh and Ha Van Sam (2012) Response Evaluations of Linear Random Waves for Reliability Based Fatigue Analysis. Proceedings of the 2nd International Conference on Engineering Mechanics and Automation (ICEMA2) Hanoi, August 16-17, 2012, ISBN: 978-604-913-097-7, pp 236-242.
  • Đào Như Mai, Nguyễn Việt Khoa, Trần Thanh Hải và Nguyễn Văn Quang (2011) Phân tích mỏi trên quan điểm độ tin cậy sử dụng mô phỏng sóng ngẫu nhiên tuyến tính.Tuyển tập Hội nghị Khoa học và Công nghệ biển toàn quốc lần thứ V, Tiểu ban: Năng lượng, kỹ thuật công trình, vận tải và công nghệ Biển, Hà Nội 2011, tr.228-235
  • Dao Nhu Mai and Nguyen Viet Khoa (2010) Reliability Analysis of Structure Using Stream Functions for Load Calculations. Proceedings of the International Conference on Engineering Mechanics and Automation-ICEMA2010, Hanoi July 1-2, 2010, ISBN-978-604-913-024-3, pp. 39-44
  • Đào Như Mai, Nguyễn Việt Khoa và Nguyễn Hữu Cường (2010) Phân tích mỏi trên quan điểm độ tin cậy.Tuyển tập công trình Hội nghị Khoa học toàn quốc Cơ học Vật rắn biến dạng lần thứ 10, 11-2010, Thái Nguyên, ISBN 978-604-915-000-5, tr. 482-489.
  • Đào Như Mai, Nguyễn Việt Khoa và Nguyễn Văn Quang (2010) Đánh giá các đặc trưng thống kê của đáp ứng cực đại sử dụng sóng Tromans bị ràng buộc.Tuyển tập công trình Hội nghị Khoa học toàn quốc Cơ học Vật rắn biến dạng lần thứ 10, 11-2010, Thái Nguyên, ISBN 978-604-915-000-5, tr. 490-498.

Patents (list):
Technological products (describe in details: technical characteristics, place):

  • Report on the Procedure and Algorithm of the Reability based Fatigue Analysis and the results of Fatigue Analysis for 3 ofshors structure in the library Institute of Mechanics
  • Computer Program in CD.