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Study On Program Of Probabilistic Damage Tolerance Risk Assessment For Holes In Turbine Disks

Posted on:2017-08-15Degree:MasterType:Thesis
Country:ChinaCandidate:Z Y YanFull Text:PDF
GTID:2322330503487927Subject:Aeronautical and Astronautical Science and Technology
Abstract/Summary:PDF Full Text Request
According to China Civil Aviation Regulations Part 33 issued by CAAC(Civil Aviation Administration of China), damage tolerance evaluation should be conducted during the progress of the airworthiness validation, for turbine disks belongs to typical life-limited part of aero-engines. At present, perfect methods and tools which are suitable for the damage tolerance evaluation on the life-limited part. In this paper which is based on relevant airworthiness files, the damage tolerance evaluation process is analyzed and summarized. After that, the probabilistic damage tolerance risk assessment procedure of holes in turbine disks is drawn out. In the end, that procedure is used to analysis of the influence of turbine disk design parameters on the turbine disk eccentric hole parts failure risk. The main research content of this paper is as follows:(1) The turbine disk damage tolerance evaluation of regulatory requirements was analyzed. Firstly, based on Federal Aviation Regulations(FAR), relevant clauses of the damage tolerance of aero-engine life limited parts in the FAR(FAR 33.70(a) terms) were technically analyzed. Then, combining with the consulting related notice(AC 33.70-1?AC 33.70-2), the process which was of the aero-engine life-limited parts of the limit damage tolerance assessment was summarized. Finally, the probability damage tolerance for turbine disk evaluation content was analyzed.(2) The probabilistic damage tolerance assessment program of holes in turbine disks was developed, and the program provided a validation tool for turbine disk damage tolerance of airworthiness compliance assessment. Assessment procedures were developed based on the principle of fracture mechanics. The low cycle fatigue stress data of turbine disk was calculated by ANSYS software, and then the simulation calculation of the low cycle fatigue on the turbine disk eccentric hole was completed by dealing with the turbine disc defect data and nondestructive inspection data with the help of using the Monte-Carlo method in the MATLAB platform. Combined with the samples, the airworthiness conformity assessment was achieved and it was about the location probability damage tolerance of the turbine disc hole. That could suggested that the program had a certain applicability.(3) Based on the developed assessment program, the influence of and the turbine design parameters to the risk of turbine disk were analyzed, and the relation between the risk of the turbine disk and design parameters was achieved. Combining with the example, these design parameters such as the limiting value of the turbine disk life, stress, eccentric hole numbers and inspection strategies of were adjusted. The failure risk conditions of turbine disk eccentric hole parts under different design parameters had been analyzed. The relation between the risk of the turbine disk and design parameters could be taken as reference to the improvement on the design of turbine disk.
Keywords/Search Tags:Aero-engine, Life-limited parts, Turbine disk, Airworthiness certification, Damage tolerance
PDF Full Text Request
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