Research on Assessment Method of Creep Buckling Strength of Titanium Alloy Pressure Shell for Deep-sea Submersible
Titanium alloy pressure shell of deep-sea submersible suffers from room-temperature creep,which can weaken the buckling ultimate strength of the pressure shell structure and lead to creep buckling failure.The paper takes titanium alloy cylindrical pressure shell as research object.Effects of initial imperfection amplitude,creep load,and creep time are considered,and influence of creep deformation on the buckling ultimate strength of pressure shell is investigated with numerical simulation.It is shown that the creep deformation exacerbates the magnitude of initial imperfection and weakens buckling ultimate strength of the pressure shell structure.In addition,creep buckling occurs in titanium alloy pressure shell.The critical time of creep buckling is extremely sensitive to the initial imperfection amplitude.An exponential model is proposed between room-temperature creep buckling critical time and creep load of titanium alloy pressure shell,which can be applied to quickly assess the maximum dive depth at a specified operating time.Relative errors between the fitting results of the proposed model and those of numerical calculations are all within±2％.
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