Research On Safety Analysis Methods Of Aircarft In The Case Of Uncontained Turbine Engine Rotor Failure

Uncontained Turbine Engine Rotor Failure (UERF) is one of typical particular risks threatening Airplane. Safety analysis of airplane in the case of uncontained rotor failure is effective method to meet deisgn requirements of uncontained safety, and to verify the requirements. For the lack of existing research work about hazard indentification and hazard quantitative assessment in the cause of multiple uncontained rotor fragments bursting out, the safety analysis of airplane in the case of uncontained rotor failure is studied in depth. A method based on the results of airplane level Functional Hazard Analysis (FHA) and using Fault Tree Analysis (FTA) is proposed, and the quantitative assessment model of hazards for different uncontained failure model is established, also the analysis method for acceptable results is proposed.The research in this paper mainly include:1 ) Definitions and assumptions for uncontained safety analysis are improved; Existing uncontained failure models are analyzed, and parameters of the uncontained model is defined; The method determining impact area is proposed; Safety analysis objective and analysis time are explicated; Finally, the process of uncontained rotor failure safety analysis is presented.2)Based on the results of airplane level FHA,method using FTA for hazard identification is studied; Firstly the method that determine catastrophic functional hazards caused by UERF is introduced, then the method and steps to establish UERF fault tree is explicated, and hazard triggering analysis method based on minimal cut sets is proposed finally.3)The parameters as spread risk angle and translational risk angle are defined, and the uncontained debris trajectory variables that consist of spread angle variable and translational angle variable is proposed; Input parameters of basic model are determined, and the basic model of hazard probability is established; Risk factors that contribute to hazard are analyzed, then Catastrophic hazard probability model for single rotor stage and mean probability model for airplane are established separately.4)For the case that hazard probability is beyond quantitative analysis objective, the hazard importance and basic event importance are studied, then the ranking method of items that need to be improved, and the principle and method to minimize the hazards caused by uncontained rotor failure is proposed. Finally, an example shows that the safety analysis method is feasible.