scholarly journals A new energy gradient-based model for LCF life prediction of turbine discs

2017 ◽  
Vol 5 ◽  
pp. 856-860 ◽  
Author(s):  
Yunhan Liu ◽  
Shun-Peng Zhu ◽  
Zheng-Yong Yu ◽  
Qiang Liu
Keyword(s):  
Life Prediction ◽  
Energy Gradient ◽  
New Energy ◽  
Gradient Based

A New Energy-Based Uniaxial Fatigue Life Prediction Method for a Gas Turbine Engine Material

2007 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
M.-H. Herman Shen ◽  
Tommy George ◽  
Charles Cross ◽  
Jeffrey Calcaterra
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Life Prediction ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Turbine Engine ◽  
Bending Fatigue ◽  
New Energy ◽  
Stress Ratios ◽  
Materials Used

A new energy-based fatigue life prediction framework for calculation of axial and bending fatigue life at various stress ratios has been developed. The purpose of the life prediction framework is to account for materials used in gas turbine engines, such as Titanium 6Al-4V, which experience an endurance stress limit as the number of cycles increase towards infinity. The work conducted to develop this energy-based framework consist of the following entities: (1) A new life prediction criterion for axial and bending fatigue at various stress ratios for Aluminum 6061-T6, (2) use of the previously developed improved uniaxial energy-based method to acquire fatigue life prior to endurance limit behavior [1], (3) and the incorporation of a statistical energy-based fatigue life calculation scheme to the uniaxial life criterion (the first entity of the framework), which is capable of constructing prediction intervals based on a specified percent confidence level. The exactitude of this work was verified by comparison between theoretical approximations and experimental results from recently acquired Al 606-T6 and Ti 6Al-4V data. The comparison shows very good agreement, thus validating the capability of the framework to produce accurate fatigue life predictions.

A Promising New Energy-Based Fatigue Life Prediction Framework

2005 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
M.-H. Herman Shen ◽  
Charles Cross ◽  
Jeffrey Calcaterra ◽  
Tommy George
Keyword(s):  
Fatigue Life ◽  
Strain Energy ◽  
Life Prediction ◽  
Total Strain ◽  
Total Strain Energy ◽  
Bending Fatigue ◽  
New Energy ◽  
Stress Ratios ◽  
Energy Dissipated ◽  
Fatigue Criterion

An energy-based fatigue life prediction framework has been developed for prediction of axial and bending fatigue life at various stress ratios. The framework for the prediction of fatigue life via energy analysis was developed in accordance with the approach in our previous study which states: the total strain energy dissipated during a monotonic fracture process is a material property that can be determined by measuring the area underneath the monotonic true stress-strain curve. The framework consists of the following two elements: (1) Development of a bending fatigue criterion by observing the total strain energy of the effective volume, which is achieved by computing the total plastic strain energy with consideration of the stress gradient influence through the thickness of a specimen, in the fatigue area, during cyclic loading. A comparison between the prediction and the experimental results from 6061-T6 aluminum specimens was conducted and shows that the new energy-based fatigue criterion is capable of predicting accurate fully reversed bending fatigue life. (2) Development of a new life prediction criterion for axial fatigue at various stress ratios. The criterion was constructed by accounting for both the residual energy dissipated, monotonically, due to the mean stress, and the incorporation of the mean stress effect into the total strain energy density dissipated per cycle. The performance of the criterion was demonstrated by experimental results from 6061-T6 aluminum dog-bone specimens subjected to axial stress at various stress ratios. The comparison shows very good agreement, thus validating the capability of producing accurate fatigue life predictions.

scholarly journals Variational quantum solver employing the PDS energy functional

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 473
Author(s):  
Bo Peng ◽  
Karol Kowalski
Keyword(s):  
Quantum Algorithms ◽  
Energy Functional ◽  
Strongly Correlated ◽  
Local Minima ◽  
New Class ◽  
Moment Expansion ◽  
Energy Gradient ◽  
Model Hamiltonian ◽  
New Energy ◽  
Quantum Approach

Recently a new class of quantum algorithms that are based on the quantum computation of the connected moment expansion has been reported to find the ground and excited state energies. In particular, the Peeters-Devreese-Soldatov (PDS) formulation is found variational and bearing the potential for further combining with the existing variational quantum infrastructure. Here we find that the PDS formulation can be considered as a new energy functional of which the PDS energy gradient can be employed in a conventional variational quantum solver. In comparison with the usual variational quantum eigensolver (VQE) and the original static PDS approach, this new variational quantum solver offers an effective approach to navigate the dynamics to be free from getting trapped in the local minima that refer to different states, and achieve high accuracy at finding the ground state and its energy through the rotation of the trial wave function of modest quality, thus improves the accuracy and efficiency of the quantum simulation. We demonstrate the performance of the proposed variational quantum solver for toy models, H2 molecule, and strongly correlated planar H4 system in some challenging situations. In all the case studies, the proposed variational quantum approach outperforms the usual VQE and static PDS calculations even at the lowest order. We also discuss the limitations of the proposed approach and its preliminary execution for model Hamiltonian on the NISQ device.

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