Loading...

Equivalent Static Analysis of fixed Offshore Platformes Under Fatigue Loads (Analyzing different failure scenarios)

Akrami, Vahid | 2010

782 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40389 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Golafshani, Ali Akbar
  7. Abstract:
  8. A structural system will normally fail as a result of a chain of failures of different components. In this thesis, fatigue reliability of fixed offshore platforms is investigated through analyzing different failure scenarios. In order to evaluate the occurrence probability of a special scenario, each failure scenario is divided into a finite number of sub-scenarios. To do this, all combinations of time sequences are generated for a given sequence of failures, using a specially developed program.
    In order to calculate the occurrence probability of each scenario, a massive reliability analysis should be done for each of corresponding sub-scenarios. Knowing that there are a large number of sub-scenarios which should be analyzed, implementing traditional methods for evaluating fatigue reliability of components may be unrealistic, and a simplified method is required. This method should have the possible highest accuracy while doing the least amount of calculations. Herein, an “Artificial transfer function (ATF)” is used to calculate the cumulative fatigue degradation in components. The preciseness of the proposed simplified method is evaluated using a numerical model, and then, it’s used to calculate the occurrence probability of each sub-scenario. Based on the calculated values, probability of occurrence is obtained for each scenario, and finally, the failure probability of entire system is calculated. The proposed method may be considered as a powerful mean for analyzing fatigue degradation of fixed offshore platforms. Using this procedure, the relative vulnerability of different failure paths may be determined and the most critical scenario can be obtained. Also, the proposed method can be used in inspection planning and evaluating the life extension of existing offshore platforms.


  9. Keywords:
  10. Static Analysis ; Fixed Offshore Platform ; Fatigue Reliability ; Failure Scenario ; Artificial Transfer Function ; Most Critical Scenario

 Digital Object List

 Bookmark

No TOC