Comparative Study of Probabilistic Structural Safety Analysis of a Titanium Pressure Vessel

Abstract

Structural Reliability (Safety Index) is a very important factor of any aerospace product. Until recently, a design was considered robust if all the variables that affected its life had been accounted for and brought under control. The meaning of robustness is shifting. Designer and engineers have traditionally handled variability with safety factors. Some safety factors are derived from observation and analysis, and many cases it used to be pure guesswork. In those cases, the bigger the guess, the bigger the risk, the bigger the safety factor, resulting over designed product. Safety factor cannot, by themselves, guarantee satisfactory performance and they do not provide sufficient information to achieve optimal use of available resources. In this paper pressure vessel made of titanium alloy is considered for structural reliability study. Structural Safety Index is evaluated using uncertainty. Various statistical methods like mean value and moment methods are discussed. Simulation techniques for evaluation of probability of failure are also discussed. Response surface methodology which helps in solving many complex structural problems has been used. Finally, comparative studies have been made for various techniques. These techniques will be useful for Reliability design evaluation.