Deep manned submersible pressure hull fatigue reliability analysis of titanium
|School||Shanghai Jiaotong University|
|Course||Design and manufacture of ships and marine structures|
|Keywords||Titanium pressure hull Fatigue Reliability Quadratic response surface method Whole life model|
The deep sea submersible submersible pressure hull is to ensure the normal operation of the main load-bearing structure , the fatigue life and reliability indicators will directly affect the overall safety performance of submersibles . This article is based on fracture mechanics approach titanium deep manned submersible pressure hull fatigue life prediction , and its fatigue reliability analysis , structural design optimization for the submersible to provide a basis and reference. Selected maximum design diving depth of 4,500 meters in the U.S. submersible Alvin dive number of historical data as a reference , which determine the depth level submersible fatigue load spectrum . Through a comparative study of different probability model , chose Gumbel distribution submersible dive depth as a probability distribution model , and through the submersible pressure on the relationship with the dive depth was fatigue load spectrum for pressure hull . Respectively, based on shell theory and finite element numerical method for pressure hull stress levels were analyzed by calculating the pressure hull submersible built to meet the specification for the static strength requirements. Fracture mechanics combined with titanium pressure hull fatigue life estimates were based on Paris crack growth model and model -based Brown-Hobson whole life fatigue crack propagation model for deterministic analysis, the results meet the design requirements. Finally integrated computational accuracy and computational efficiency of selection does not contain cross terms quadratic response surface method as the pressure hull fatigue reliability calculation method, and Paris respectively, based on model and model -based Brown-Hobson whole life models were reliability index calculations and parameter sensitivity analysis , the values ??for each parameter selection and depth of dive operations to provide a reference . Combined with the results from the model analysis, taking into account the whole life model of short crack propagation stage so that it can better describe the crack propagation process , more accurate results than the Paris model , more suitable for submersible pressure hull .