A special CAD/CAM software for electro-discharge machining of shrouded turbine blisks

In this paper, a special-purpose CAD/CAM software package, BliskCad/Cam, based on a commercial CAD/CAM software Unigraphics is developed to reduce difficulties in CNC-EDM of the shrouded turbine blisks. The software package consists of five modules such as electrode design, path searching, and machining simulation module. Functions of BliskCad/Cam include parametrical reconstruction of 3-D model of the blisk, intelligent design of complex shaped electrode, automatic generation of NC codes, search of interference-free tool path for multi-axis NC-EDM and machining simulation, etc. Experimental verification is conducted by using BliskCad/Cam and the results show that it satisfies the requirements, and can realize precision machining and reduce accessorial time remarkably.

Deep learning-based modeling method for probabilistic LCF life prediction of turbine blisk

Turbine blisk is one of the typical components of gas turbine engines.The fatigue life of turbine blisk directly affects the reliability and safety of both turbine blisk and aeroengine whole-body.To monitor the performance degradation of an aeroengine,an efficient deep learning-based modeling method called convolutional-deep neural network(C-DNN)method is proposed by absorbing the advantages of both convolutional neural network(CNN)and deep neural network(DNN),to perform the probabilistic low cycle fatigue(LCF)life prediction of turbine blisk regarding uncertain influencing parameters.In the C-DNN method,the CNN method is used to extract the useful features of LCF life data by adopting two convolutional layers,to ensure the precision of C-DNN modeling.The two close-connected layers in DNN are employed for the regression modeling of aeroengine turbine blisk LCF life,to keep the ac-curacy of LCF life prediction.Through the probabilistic analysis of turbine blisk and the com-parison of methods(ANN,CNN,DNN and C-DNN),it is revealed that the proposed C-DNN method is an effective mean for turbine blisk LCF life prediction and major factors affecting the LCF life were gained,and the method holds high efficiency and accuracy in regression modeling and simulations.This study provides a promising LCF life prediction method for complex structures,which contribute to monitor health status for aeroengines operation.

Advanced multiple response surface method of sensitivity analysis for turbine blisk reliability with multi-physics coupling

To reasonably implement the reliability analysis and describe the significance of influencing parameters for the multi-failure modes of turbine blisk, advanced multiple response surface method (AMRSM) was proposed for multi-failure mode sensitivity analysis for reliability. The mathematical model of AMRSM was established and the basic principle of multi-failure mode sensitivity analysis for reliability with AMRSM was given. The important parameters of turbine blisk failures are obtained by the multi-failure mode sensitivity analysis of turbine blisk. Through the reliability sensitivity analyses of multiple failure modes (deformation, stress and strain) with the proposed method considering fluid-thermal-solid interaction, it is shown that the comprehensive reliability of turbine blisk is 0.9931 when the allowable deformation, stress and strain are 3.7 x 10(-3) m, 1.0023 x 10(9) Pa and 1.05 x 10(-2) m/m, respectively; the main impact factors of turbine blisk failure are gas velocity, gas temperature and rotational speed. As demonstrated in the comparison of methods (Monte Carlo (MC) method, traditional response surface method (RSM), multiple response surface method (MRSM) and AMRSM), the proposed AMRSM improves computational efficiency with acceptable computational accuracy. The efforts of this study provide the AMRSM with high precision and efficiency for multi-failure mode reliability analysis, and offer a useful insight for the reliability optimization design of multi-failure mode structure. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

A discussion of fatigue properties of notched specimens subjected to prestressing treatment machined from FGH4097

Experimental and numerical investigations were performed to reveal the effect of prestress on the fatigue properties of FGH4097 so as to quantitatively evaluate the overspeed benefit of the disc of aeroengine. A corresponding experiment was performed to examine the effect of prestress on the fatigue life of FGH97. A complete model describing the fatigue properties of the prestressed notch specimen was proposed. After the modification of mean stress, stress gradient and prestressing treatment, the model is finally verified by fatigue test of presstressed notch specimens machined from FGH4097 with satisfactory accuracy and good engineering applicability. The new model highlights that for the variable fatigue loads, the introduction of appropriate prestress is expected to benefit to the notch specimens and certainly to the disc of aeroengine regards of their fatigue properties. Both the calculation method of fatigue life parameters and the prestress correction model are proved to have good prediction accuracy.