Interval Nonprobabilistic Analysis Based on a Dynamic Substructural Collaborative Finite-Element Method for Aeroengine Blisks

摘要

Based on fewer uncertain parameters of aeroengine blisks in statistics, a new measurement methodology is presented, which is called the interval nonprobabilistic analysis based on the dynamic substructural collaborative finite-element method (INP-DSFEM). Firstly, on the basis of the basic theory of nonprobabilistic reliability analysis, the definition of uncertainty and its extension are proposed. The expression formula of performance function is also deduced. Then, the interval variables and interval matrix of blisks are investigated, including the reduced interval bladed model, reduced interval disk model, and comprehensive hybrid interface reduced interval blisks model; moreover, the interval finite-element dynamics equation is also built. The basic thought of this method is to compare the performance range with the structural requirement range to determine the extent of security and reliability. The system will be at failure if the performance range is beyond the requirement range; however, if the performance range is in the requirement range, the system will be safe. When the upper and lower performance boundaries are not near the structural requirement, the structural range limitation of the uncertain parameter is smaller, and the structural robustness parameter is greater. It is a convenient calculation, and the permission variation boundary of uncertain parameters can be given explicitly. Finally, the nonprobabilistic analysis of blisks is investigated by INP-DSFEM, and the uncertainty of modal and vibratory response for tuned and mistuned blisks are calculated by INP-DSFEM; compared with those for the tuned blisks, the uncertainties of the modal and vibratory response for the mistuned blisks decreased. Meanwhile, a method called interval nonprobabilistic-ellipsoidal convex model (INP-ECM) is adopted to verify the reasonability and effectiveness of INP-DSFEM. Therefore, the presented methodology in this paper is a choice for the reliability calculation of aeroengine blisks, which is as a beneficial supplement for the probabilistic analysis. (C) 2017 American Society of Civil Engineers.