The Impact of the Manufacturing Quality of Gas Turbine Engine Components on the Life Test Efficiency Criteria

The paper examines the impact of gas turbine engine component manufacturing quality on the efficiency criteria of its life test. Known methods for selecting test parameters apply maximum damageability equivalence and minimum test time as test efficiency criteria. This study also proposes taking into account the maximization of engine lifecycle profits through the proper selection of test parameters. Engine components that determine its life were selected: the turbine blade, rotor bearing, reducer driving gear, fan bearing, and DC and AC generators. Both the mathematical expectation and variance of the quality parameters were varied during the study. The manufacturing quality of engine components and assemblies is characterized by geometric, mechanical, and physical parameters. These parameters include bearing fit diameters, initial radial clearance, turbine blade geometry, mechanical properties and gear shape, generator insulation quality, and others. Parameters selection was based on the life cycle simulation model. The following results were obtained in the course of the study: (1) Manufacturing accuracy has a more significant impact on test results than deviations from mean values of initial state parameters; (2) Despite the fact that variation in production parameters from the standard values do not affect the comparability of test results, they lead to an acceleration of the testing process. At the same time, this entails a decrease in overall economic efficiency throughout the entire life cycle of the product; (3) The overall profitability of a production run of engines is primarily determined by the quality characteristics of the turbine blades, and least on fan bearing quality parameters; (4) in the case where there is a full guarantee of engine component manufacturing quality, only short-term (acceptance, control) tests can be carried out.