scholarly journals Similitude for the Dynamic Characteristics of Dual-Rotor System with Bolted Joints

Mathematics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 3
Author(s):  
Lei Li ◽  
Zhong Luo ◽  
Fengxia He ◽  
Zhaoye Qin ◽  
Yuqi Li ◽  
...  
Keyword(s):  
High Pressure ◽  
Dynamic Characteristics ◽  
Low Pressure ◽  
Full Scale ◽  
Rotor System ◽  
Bolted Joints ◽  
Scaled Model ◽  
Scaling Relationships ◽  
Counter Rotation ◽  
Vibration Responses

The dual-rotor system has been widely used in aero-engines and has the characteristics of large axial size, the interaction between the high-pressure rotor and low-pressure rotor, and stiffness nonlinearity of bolted joints. However, the testing of a full-scale dual-rotor system is expensive and time-consuming. In this paper, the scaling relationships for the dual-rotor system with bolted joints are proposed for predicting the responses of full-scale structure, which are developed by generalized and fundamental equations of substructures (shaft, disk, and bolted joints). Different materials between prototype and model are considered in the derived scaling relationships. Moreover, the effects of bolted joints on the dual-rotor system are analyzed to demonstrate the necessity for considering bolted joints in the similitude procedure. Furthermore, the dynamic characteristics for different working conditions (low-pressure rotor excitation, high-pressure rotor excitation, two frequency excitations, and counter-rotation) are predicted by the scaled model made of a relatively cheap material. The results show that the critical speeds, vibration responses, and frequency components can be predicted with good accuracy, even though the scaled model is made of different materials.

scholarly journals Intelligent Approach to Robust Design Optimization of a Rotor System due to Its Support Stiffness Uncertainty

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Bensheng Xu ◽  
Chaoping Zang ◽  
Genbei Zhang
Keyword(s):  
Design Optimization ◽  
Robust Design ◽  
System Performance ◽  
Polynomial Chaos ◽  
Low Pressure ◽  
Polynomial Chaos Expansion ◽  
Rotor System ◽  
Robust Design Optimization ◽  
Chaos Expansion ◽  
Vibration Responses

In this paper, an intelligent robust design approach combined with different techniques such as polynomial chaos expansion (PCE), radial basis function (RBF) neural network, and evolutionary algorithms is presented with a focus on the optimization of the dynamic response of a rotor system considering support stiffness uncertainty. In the proposed method, the PCE method instead of the traditional Monte Carlo uncertainty analysis is applied to analyze the uncertain propagation of system performance. The RBF network is introduced to establish the approximate models of the objective and constraint functions. Taking the low-pressure rotor of a gas turbine with support stiffness uncertainty as an example, the optimization model is established with the mean and variance of unbalanced response of the rotor system at different operating speeds as the objective function, and the maximum unbalance response is less than the upper limit as the constraint function. The polynomial chaos expansion is generated to facilitate a rapid analysis of robustness in the presence of support stiffness uncertainties that is defined in terms of tolerance with good accuracy. The optimal Hypercubus are used as experimental plans for building RBF approximation models of the objective and constraint functions. Finally, the robust solutions are obtained with the multiobject optimization algorithm NSGA-II. Monte Caro simulation analysis demonstrates that the qualified rate of maximum vibration responses of the low-pressure rotor system can be increased from 83.6% to over 99%. This approach to robust design optimization is shown to lead to designs that significantly decrease vibration responses of the rotor system and improved system performance with reduced sensitivity to support stiffness uncertainty.

scholarly journals Modeling and Dynamic Characteristics Analysis of Blade-Disk Dual-Rotor System

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Zhenyong Lu ◽  
Shun Zhong ◽  
Huizheng Chen ◽  
Yushu Chen ◽  
Jiajie Han ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Critical Speed ◽  
Low Pressure ◽  
Second Order ◽  
Rotor System ◽  
Order Resonance ◽  
First Order ◽  
Cantilever Structure ◽  
Pressure Compressor

In this paper, a simplified dynamic model of a dual-rotor system coupled with blade disk is built, and the effects of blade parameters of an aircraft engine on the dynamic characteristics of a dual-rotor system are studied. In the methodology, the blade is simplified as a cantilever structure, and the dynamical equations are obtained by the means of a finite element method. The amplitude-frequency response curves and orbits of shaft centre-vibration shape diagram are used to analyze the effects of blade parameters on dynamic characteristics of a dual-rotor system. The results indicate that the properties of the blades have huge impacts on the critical speed and other dynamic characteristics of the system. With an increase of the length of the blade, the second-order critical speed decreases obviously, but the first-order critical speed is almost invariant; this means that the blades attached on the low-pressure compressor do not affect the first-order critical speed of the dual-rotor system. Meanwhile, note that the high-pressure rotor and low-pressure turbine rotor can excite the first-order resonance of the dual-rotor system, while the low-pressure compressor rotor can only excite the second-order resonance, and then the dynamic model of this six-point support dual-rotor system can further be simplified as a relatively independent single-rotor system with one disk and a four-support dual-rotor system with dual disks.

Dynamic investigation of aeroengine high pressure rotor system considering assembly characteristics of bolted joints

2020 ◽  
Vol 112 ◽  
pp. 104510
Author(s):  
Wei Sun ◽  
Tao Li ◽  
Dongjian Yang ◽  
Qingchao Sun ◽  
Junzhou Huo
Keyword(s):  
High Pressure ◽  
Rotor System ◽  
Bolted Joints ◽  
Dynamic Investigation

Fouling Is the Beginning: Upcycling Biopolymer-Fouled Substrates for Fabricating High-Permeance Thin-Film Composite Polyamide Membranes

2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
High Pressure ◽  
End Of Life ◽  
Water Purification ◽  
Low Pressure ◽  
Polymeric Membranes ◽  
Membrane Recycling ◽  
Film Composite ◽  
Thin Film Composite ◽  
First Time

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.

Experimental study of the strength and durability of metal-composite high-pressure tanks

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 49-56 ◽  
Author(s):  
A. M. Lepikhin ◽  
V. V. Moskvichev ◽  
A. E. Burov ◽  
E. V. Aniskovich ◽  
A. P. Cherniaev ◽  
...  
Keyword(s):  
High Pressure ◽  
Strain State ◽  
Full Scale ◽  
Fracture Mechanisms ◽  
Metal Composite ◽  
Test Results ◽  
Stress Strain ◽  
Pneumatic Pressure ◽  
Stress Strain State ◽  
Composite Tank

The results of unique experimental studies of the strength and service life of a metal-composite high-pressure tank are presented. The goal of the study is to analyze the fracture mechanisms and evaluate the strength characteristics of the structure. The methodology included tests of full-scale samples of the tank for durability under short-term static, long-term static and cyclic loading with internal pneumatic pressure. Generalized test results and data of visual measurements, instrumental and acoustic-emission control of deformation processes, accumulation of damages and destruction of full-scale tank samples are presented. Analysis of the strength and stiffness of the structure exposed to internal pneumatic pressure is presented. The types of limiting states of the tanks have been established experimentally. Change in the stress-strain state of the tank under cyclic and prolonged static loading is considered. Specific features of the mechanisms of destruction of a metal-composite tank are determined taking into account the role of strain of the metal liner. The calculated and experimental estimates of the energy potential of destruction and the size of the area affected upon destruction of the tank are presented. Analysis of test results showed that the tank has high strength and resource characteristics that meet the requirements of the design documentation. The results of the experiments are in good agreement with the results of numerical calculations and analysis of the stress-strain state and mechanisms of destruction of the metal-composite tank.

scholarly journals High-Pressure Spectroscopy Study of Zn(IO3)2 Using Far-Infrared Synchrotron Radiation

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Akun Liang ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Ibraheem Yousef ◽  
Catalin Popescu ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Synchrotron Radiation ◽  
Infrared Radiation ◽  
Room Temperature ◽  
Far Infrared ◽  
Low Pressure ◽  
Pressure Response ◽  
Spectroscopy Study ◽  
Far Infrared Radiation

We report the first high-pressure spectroscopy study on Zn(IO3)2 using synchrotron far-infrared radiation. Spectroscopy was conducted up to pressures of 17 GPa at room temperature. Twenty-five phonons were identified below 600 cm−1 for the initial monoclinic low-pressure polymorph of Zn(IO3)2. The pressure response of the modes with wavenumbers above 150 cm−1 has been characterized, with modes exhibiting non-linear responses and frequency discontinuities that have been proposed to be related to the existence of phase transitions. Analysis of the high-pressure spectra acquired on compression indicates that Zn(IO3)2 undergoes subtle phase transitions around 3 and 8 GPa, followed by a more drastic transition around 13 GPa.

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