scholarly journals Whole Engine Interaction in a Bladed Rotor-to-Stator Contact

2014 ◽  
Author(s):  
Marie-Océane Parent ◽  
Fabrice Thouverez ◽  
Fabrice Chevillot
Keyword(s):  
Aircraft Engine ◽  
Special Focus ◽  
Aero Engine ◽  
Elastic Link ◽  
Bladed Rotor ◽  
Engine Dynamic ◽  
Fan Blade ◽  
Model Components ◽  
Type Of Behavior ◽  
Fully Coupled

Reducing the clearances between rotating and fixed parts is an important factor in increasing the performances of turbomachines. The physical counterpart however is an evolution in possible rotor-stator contacts capable of causing unstable dynamic behavior. A proper prediction of the rotor-stator contact occurrences and associated induced phenomena, has therefore become of a great interest for aero-engine mechanical engineers. Most numerical simulations involving rotor-stator contact can be divided into two types of physical behavior. The first focuses on contact induced blade/casing interactions, in only taking into account the blades and casing flexibility. The second type of behavior takes into account the shaft dynamic while neglecting blade flexibility. Future designs of aircraft engines will however raise the need to combine these two types of models. Since, the structural components are more flexible, the dynamic coupling between engine modules is increased. This paper proposes a study based on a structure representative of the whole aircraft engine, including the contacts that may arise between the fan-blade tips and fan casing. We have introduced a fully-coupled phenomenological model with flexible blades, shaft and casing. Furthermore, this model includes an elastic link between shaft and casing to simulate the fan frame behavior. We begin by explaining the linear results, which highlight the dynamic couplings between these various model components. During a second step, this paper presents the nonlinear results obtained by introducing a contact law. These results demonstrate the influence of the whole engine dynamic on contact-related behavior with special focus on the system dynamic stability.

scholarly journals Strength Assessment of Fan Blade with Different Materials

2019 ◽  
pp. 266-283
Author(s):  
Polyminna Dileep ◽  
C. Mohan Naidu
Keyword(s):  
Structural Analysis ◽  
Weight Reduction ◽  
Fuel Efficiency ◽  
Aircraft Engine ◽  
Sandwich Composite ◽  
Strength Assessment ◽  
Static And Dynamic Analysis ◽  
Composite Blade ◽  
Aero Engine ◽  
Fan Blade

Weight reduction of turbofan engines is one of the main concerns of aero engine manufacturers in order to cut fuel burn. To achieve higher fuel efficiency, aero engine manufacturers develop turbofans with higher bypass ratio, which can only be achieved with larger (and heavier) fan sections. This makes weight reduction in fan components a major consideration and becomes a key driver for the use of composite materials in future engines. The objective of this project is to design, perform structural analysis and optimization of a Composite fan blade. Development of a fan blade is comparable to a future large aircraft engine fan blade. This thesis is about the structural analysis of a composite fan blade with a honeycomb sandwich construction with a polymer matrix composite and honeycomb Aluminium core compared with baseline solid basic fan blade made of titanium. The focus of this work is to design the sandwich composite blade with honeycomb core and conduct static and dynamic analysis.

Aero-engine dynamic model based on an improved compact propulsion system dynamic model

2021 ◽  
pp. 095965182098408
Author(s):  
Qiangang Zheng ◽  
Yong Wang ◽  
Chongwen Jin ◽  
Haibo Zhang
Keyword(s):  
Dynamic Model ◽  
Propulsion System ◽  
System Dynamic ◽  
Inlet Temperature ◽  
System Dynamic Model ◽  
Component Level ◽  
Engine Model ◽  
Surge Margin ◽  
Aero Engine ◽  
Engine Dynamic

The modern advanced aero-engine control methods are onboard dynamic model–based algorithms. In this article, a novel aero-engine dynamic modeling method based on improved compact propulsion system dynamic model is proposed. The aero-engine model is divided into inlet, core engine, surge margin and nozzle models for establishing sub-model in the compact propulsion system dynamic model. The model of core engine is state variable model. The models of inlet, surge margin and nozzle are nonlinear models which are similar to the component level model. A new scheduling scheme for basepoint control vector, basepoint state vector and basepoint output vector which considers the change of engine total inlet temperature is proposed to improve engine model accuracy especially the steady. The online feedback correction of measurable parameters is adopted to improve the steady and dynamic accuracy of model. The modeling errors of improved compact propulsion system dynamic model remain unchanged when engine total inlet temperature of different conditions are the same or changes small. The model accuracy of compact propulsion system dynamic model, especially the measurable parameters, is improved by online feedback correction. Moreover, the real-time performance of compact propulsion system dynamic model and improved compact propulsion system dynamic model are much better than component level model.

A General Ply Design for Aero Engine Composite Fan Blade

2017 ◽  
Author(s):  
Jiaguangyi Xiao ◽  
Yong Chen ◽  
Qichen Zhu ◽  
Jun Lee ◽  
Tingting Ma
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Stacking Sequence ◽  
Composite Blade ◽  
Arduous Task ◽  
Aero Engine ◽  
Margin Of Safety ◽  
Fan Blade ◽  
The Impact ◽  
Ply Orientation

Composite fan blade ply lay-up design, which includes ply drop-off/shuffle design and stacking sequence design, makes fan blade structures different from traditional composite structures. It gives designers more freedom to construct high-quality fan blades. However, contemporary fan blade profiles are quite complex and twisted, and fan blade structures are quite different from regular composite structures such as composite laminates and composite wings. The ply drop-off design of a fan blade, especially for a fully 3D fan blade, is still an arduous task. To meet this challenge, this paper develops a ply lay-up way with the help of a software called Fibersim. The fully 3D fan blade is cut into ply pieces in Fibersim. As a result, an initial ply sequence is created and ply shuffle could revise it. Because of the complexity of ply shuffling, the ply shuffle table developed in this paper mainly refers to the design experience gained from simple plate-like laminate structures and some criterion. Besides, the impact of different ply orientation patterns on the reliability of composite fan blade is studied through static and modal numerical analysis. The results show that this ply lay-up idea is feasible for aero engine composite fan blade. Under the calculated rotating speeds, the ply stacking sequence 4 (i.e.[−45°/0°/+45°/0°] with the outer seven groups are [−45°/0°/−45°/0°]) shows the greatest margin of safety compared with other stacking sequences. Modal analysis shows that plies with different angles could have relatively big different impacts on blades vibration characteristics. The composite fan blade ply design route this paper presents has gain its initial success and the results in this paper might be used as basic references for composite blade initial structural design.

A Study on the Effect of Bird Hit Damage on the Dynamic Response of Aero-Engine Fan Blade

2013 ◽  
Author(s):  
Hithesh Channegowda ◽  
Raghu V. Prakash ◽  
Anandavel Kaliyaperumal
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Foreign Object Damage ◽  
Aero Engine ◽  
Need To Evaluate ◽  
Bird Impact ◽  
Post Impact ◽  
Fan Blade ◽  
Critical Components

Fan blades of an aero-engine assembly are the critical components that are subjected to Foreign Object Damage (FOD) such as bird impact. Bird impact resulting in deformation damage onto set of blades, which in turn alters the blade mass and stiffness distribution compared to undamaged blades. This paper presents the numerical evaluation of dynamic characteristics of bird impact damaged blades. The dynamic characteristics evaluated are the natural frequencies and mode shapes of post impact damaged set of blades and the results are compared with undamaged set of blades. The frequencies and mode shapes are evaluated for the damaged blades, with varying angles of bird impact and three blade rotational speeds. Study reveals that first bending and torsional frequencies of deformed blades are significantly affected compared to undamaged set of blades. Study emphasize the need to evaluate the natural frequencies deformed blades, that has direct bearing on High Cycle Fatigue (HCF) life of the blade, to ensure post damaged blades operate safely for certain time to reduce inflight accidents and safe landing.

scholarly journals A Numerical Method Used for the Simulation of Self-Excited Vibrations that Arise in the Aircraft Engine Fan Blade Ring

2020 ◽  
Vol 0 (2) ◽  
pp. 12-18
Author(s):  
Viacheslav Vladimirovich Donchenko ◽  
Vitaly Isaevich Gnesin ◽  
Lyubov Vladimirovna Kolodyzhnaya ◽  
Igor Fedorovich Kravchenko ◽  
Oleksii Vladimirovich Petrov
Keyword(s):  
Numerical Method ◽  
Aircraft Engine ◽  
Blade Ring ◽  
Fan Blade

scholarly journals LINEAR FRICTION WELDING – PROCESS CONTROL AND MACHINE TECHNOLOGY

2020 ◽  
Vol 321 ◽  
pp. 04019
Author(s):  
N. PIOLLE
Keyword(s):  
Friction Welding ◽  
Welding Process ◽  
Good Control ◽  
Aircraft Engine ◽  
Sensor Technology ◽  
Joint Interface ◽  
Special Focus ◽  
Linear Friction Welding ◽  
Linear Friction ◽  
Weld Parameters

Linear Friction Welding (LFW) is well adapted to produce titanium aircraft engine and structure parts, as an alternative to machining from solid, from forging or from electron beam welded blanks. The process can be described through a small number of mechanical variables: the amplitude and frequency of oscillation motion, the contact pressure and the axial displacement resulting of hot material flowing outside of the joint interface. Nonetheless, because of the high speeds and loads, the correct control and monitoring of linear friction welding requires special care on machine and tooling design. The main principles of LFW machine design are described, with a special focus on the consistency between process quality requirements and machine characteristics: the static and dynamic machine behavior, the control system performance, the sensor technology and the tooling clamping solutions shall allow a good control of the weld parameters and an accurate monitoring of the physical phenomena at the joint interface.

Prediction of transient vibration response of dual-rotor-blade-casing system with blade off

2019 ◽  
Vol 233 (14) ◽  
pp. 5164-5176 ◽  
Author(s):  
Nanfei Wang ◽  
Chao Liu ◽  
Dongxiang Jiang
Keyword(s):  
Transient Response ◽  
Rotor Blade ◽  
Vibration Amplitude ◽  
Impact Load ◽  
Transient Vibration ◽  
Vibration Displacement ◽  
Highly Nonlinear ◽  
Aero Engine ◽  
Fan Blade ◽  
The Impact

Fan blade off occurring in a running rotor of the turbofan engine dual-rotor system will cause a sudden unbalance and inertia asymmetry, which results in large impact load and consequently induces the rubbing between blade and casing. In order to reveal the transient dynamic response characteristics of actual aero-engine when fan blade off event occurs, the dynamic model of dual-rotor-blade-casing system is developed, in which the distribution characteristics of the stiffness and mass, the load transfer, and the coupling effects of dual-rotor and casing are included. Considering several excitations caused by blade off, the physical process and mechanical characteristics of the fan blade off event are described qualitatively. Considering that only the casing acceleration signal can be used for condition monitoring in actual aero-engine, the transient response including rotor vibration displacement and casing vibration acceleration during the instantaneous status are obtained. Due to the time-varying and highly nonlinear characteristics of vibration responses, frequency slice wavelet transform is employed to isolate the vibration signal features. The results show that the impact load induced by the sudden imbalance causes significant increase of vibration amplitude. The rubbing action between blade and rotor will impose constraint effects on the rotor, which decreases the transient vibration amplitude. The inertia asymmetry has a big impact on the transient response. The vibration characteristics of casing acceleration under blade off are similar to those of rotor displacement, while casing acceleration response attenuates to stable value faster and is more sensitive to high-frequency components of vibration.

Unique Challenges for Bolted Joint Design in High-Bypass Turbofan Engines

2003 ◽  
Author(s):  
Robert P. Czachor
Keyword(s):  
High Speed ◽  
Analytical Techniques ◽  
Aircraft Engine ◽  
Bolted Joints ◽  
Turbine Engines ◽  
Bolted Joint ◽  
Turbofan Engines ◽  
Component Test ◽  
Structural Failures ◽  
Fan Blade

Bolted joints are used at numerous locations in the rotors and carcass structure of modern aircraft turbine engines. This application makes the design criteria and process substantially different from that used for other types of machinery. Specifically, in addition to providing engine alignment and high-pressure gas sealing, aircraft engine structural joints can operate at high temperatures and may be required to survive very large applied loads which can result from structural failures within the engine, such as the loss of a fan blade. As engine bypass ratios have increased in order to improve specific fuel consumption, these so-called “Ultimate” loads increasingly dominate the design of bolted joints in aircraft engines. This paper deals with the sizing and design of both bolts and lever flanges to meet these demanding requirements. Novel empirical methods, derived from both component test results and correlated analysis have been developed to perform strength evaluation of both flanges and bolts. Discussion of analytical techniques in use includes application of the LS-DYNA™ code for modeling of high-speed blade impact events as related to bolted joint behavior.

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