High Efficiency Active Damping on a Fan Rotor Blade in Case Of Resonant Vibrations by Means of Piezoelectric Actuators

2021 ◽  
Author(s):  
Andrea Rossi ◽  
Fabio Botta ◽  
Ambra Giovannelli ◽  
Nicola Pio Belfiore
Keyword(s):  
Rotor Blade ◽  
Structural Integrity ◽  
High Efficiency ◽  
Forced Response ◽  
Active Damping ◽  
Resonant Excitation ◽  
Resonant Vibration ◽  
Flow Distortion ◽  
Element Analysis ◽  
Novel Approach

Abstract Severe resonant vibration is one of the main roots of turbomachinery blades failure. Forced response issues arise when the blades work in non-uniform flow fields. As a result unsteady aerodynamic pressures occur on the surfaces of the blade. If the frequency of the aerodynamic excitation matches an eigenfrequency of the blade, the vibration level may considerably increase and a drop in the life-cycle of the component could be entailed. The resonant vibration conditions could be identified at the design level by means of the Campbell diagram. Unfortunately, it is not possible to avoid all the resonant conditions, hence the mitigation of vibration has always been of the utmost importance for turbomachinery designers. Moreover an active damping system based on piezoelectric (PZT) actuators which is capable of tuning its behavior according to the resonant excitation, may be considered very attractive. In this work the forced response of a fan rotor blade, due to a stationary inlet flow distortion resulting from the presence of upstream struts, is taken into account. Some resonant conditions have been analyzed by means of Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) simulations. Thereafter a novel approach based on a proper distribution of the potential supplied to the electrodes of each PZT pair, in order to maximize the damping efficiency, is applied to the case of a plausible fan blade. The outcomes show that the proposed system is able to efficiently damp each resonant excitation and enhance the structural integrity of the blade.

Forced Response Excitation Due to the Stator Vanes of Two and Three Compressor Stages Away

2021 ◽  
Author(s):  
Toshimasa Miura ◽  
Naoto Sakai ◽  
Naoki Kanazawa ◽  
Kentaro Nakayama
Keyword(s):  
Gas Turbines ◽  
Rotor Blade ◽  
High Efficiency ◽  
Potential Effect ◽  
Forced Response ◽  
Rotor Blades ◽  
Test Facility ◽  
Blade Vibration ◽  
Stator Vane ◽  
Aero Engines

Abstract State-of-the-art axial compressors of gas turbines employed in power generation plants and aero engines should have both high efficiency and small footprint. Thus, compressors are designed to have thin rotor blades and stator vanes with short axial distances. Recently, problems of high cycle fatigue (HCF) associated with forced response excitation have gradually increased as a result of these trends. Rotor blade fatigue can be caused not only by the wake and potential effect of the adjacent stator vane, but also by the stator vanes of two, three or four compressor stages away. Thus, accurate prediction and suppression methods are necessary in the design process. In this study, the problem of rotor blade vibration caused by the stator vanes of two and three compressor stages away is studied. In the first part of the study, one-way FSI simulation is carried out. To validate the accuracy of the simulation, experiments are also conducted using a gas turbine test facility. It is found that one-way FSI simulation can accurately predict the order of the vibration level. In the second part of the study, a method of controlling the blade vibration is investigated by optimizing the clocking of the stator vanes. It is confirmed that the vibration amplitude can be effectively suppressed without reducing the performance. Through this study, ways to evaluate and control the rotor blade vibration are validated.

Modelling the Fabrication of a Pressure Vessel Toroidal Seal

2007 ◽  
Author(s):  
N. A. Leggatt ◽  
R. Dennis ◽  
P. R. Hurrell ◽  
S. E. Gould ◽  
R. R. Kane
Keyword(s):  
Pressure Vessel ◽  
Structural Integrity ◽  
Creep Behaviour ◽  
Post Weld Heat Treatment ◽  
Element Analysis ◽  
Hardening Law ◽  
Novel Approach ◽  
History Of ◽  
Manufacturing History ◽  
Integrity Analysis

Welding remains the key process in fabricating, as well as repairing, pressure vessel systems. Unfortunately, many manufacturing and through life service problems occur in or near welded regions. The through life integrity of welded components, e.g. distortion, fatigue, fracture, metallurgy and corrosion control remains a key challenge for structural integrity. The work reported in this paper investigates the complex manufacture and assembly of a pressure vessel toroidal seal. The seal is first created by depositing a series of austenitic welds onto a ferritic pressure vessel to build up a plinth, thus forming a transition weld. The transition weld is then subject to a high temperature Post Weld Heat Treatment (PWHT) to stress relieve the welds and to temper the HAZ in the welds. An austenitic toroidal ring is positioned onto the plinths and welded in place thus forming the toroidal seal. The seal is manufactured from a 347 austenitic stainless steel comprising good ductility and corrosion resistance. The manufacture of the seal is simulated using 2D axisymmetric finite element analysis that are available to support both the design and integrity analysis of welded components. As well as the inherent residual stresses associated with welding, additional effects are important, for instance the austenitic to ferritic transition welds between the vessel body and plinths. This paper presents a novel approach to the simulation of weld metal deposition that is ideally suited to the modelling of transition welds and subsequent PWHT. The plinth welds undergo PWHT and so the creep behaviour of the welds is simulated. A series of intermittent as well as end of manufacture PWHT’s are investigated. Additionally the choice of material hardening law for the austenic weldment is studied. The full manufacturing history of the seal is taken into account within the analysis including welding, component machining and component geometry fit up.

Forced Response Excitation due to the Stator Vanes of Two and Three Compressor Stages Away

2021 ◽  
Author(s):  
Toshimasa Miura ◽  
Naoto Sakai ◽  
Naoki Kanazawa ◽  
Kentaro Nakayama
Keyword(s):  
Gas Turbines ◽  
Rotor Blade ◽  
High Efficiency ◽  
Computational Cost ◽  
Forced Response ◽  
Test Facility ◽  
Vibration Level ◽  
Blade Vibration ◽  
High Rotational Speed ◽  
Axial Compressors

Abstract State-of-the-art axial compressors of gas turbines employed in power generation plants and aero engines should have both high efficiency and small footprint. Thus, in many cases, axial compressors are designed to have thin rotor blades and stator vanes with short axial distances, and are driven at high rotational speed. Recently, problems of high cycle fatigue (HCF) associated with forced response excitation have gradually increased as a result of these trends. Rotor blade fatigue can be caused not only by the wake and potential effect of the adjacent stator vane, but also by the stator vanes of two, three or four compressor stages away. Thus, accurate prediction and suppression method of them under the resonance condition are necessary in the design process. Concerning the forced response excitation associated with the adjacent stator vanes, there are many previous studies on simulating the vibration by fluid structure interaction (FSI) simulation. In these studies, the aerodynamic force acting on the blade is simulated by an efficient unsteady computational fluid dynamics (CFD) method such as the nonlinear harmonic (NLH) method. These methods can be available in commercial CFD solvers and can significantly reduce computational cost. However, there are few examples of the problems associated with the stator vanes from two and three compressor stages away and no efficient simulation method is available. In this study, the problem of rotor blade vibration caused by the stator vanes of two and three compressor stages away is studied. Ways to accurately predict and effectively control the vibration are also investigated. In the first part of the study, one-way FSI simulation is carried out using a full annulus CFD model. To validate the accuracy of the simulation, experiments are also conducted using a gas turbine test facility. The vibration level of the blade is measured using a blade tip timing (BTT) measurement system and the obtained results are compared with the simulated data. It is found that one-way FSI simulation can accurately predict the order of the vibration level. In the second part of the study, a method of controlling the forced response excitation is investigated by optimizing the clocking of the stator vanes. It is confirmed that by controlling the clocking of the stator vanes, the vibration amplitude can be effectively suppressed without reducing the compressor performance. Through this study, ways to evaluate and control the unsteady pressure force and vibration response of the rotor blade are validated. By optimizing the clocking of stator vanes, the blade vibration level can be effectively reduced.

Pipeline Integrity Management System: A New Method for Monitoring Pipeline Structural Integrity During Offshore Pipe-Lay

2007 ◽  
Author(s):  
Vincent Cocault-Duverger ◽  
Brett Howard
Keyword(s):  
Dynamic Analysis ◽  
Real Time ◽  
Structural Integrity ◽  
Structural Response ◽  
Accurate Information ◽  
Element Analysis ◽  
Monitoring Method ◽  
Time Motion ◽  
Novel Approach ◽  
Integrity Management

Traditionally, the monitoring of the pipeline structural response to dynamic loads during offshore installation is performed indirectly by comparing the observed sea-states to a matrix of pre-run dynamic analysis cases. Offshore work is planned within a weather window such that the vessel’s station keeping and equipment capacities are not exceeded and pipeline integrity remains within code limits. Assessment of actual seastate offshore is subject to interpretation, possibly introducing undue conservatism with respect to pipe lay operations in some circumstances. This paper describes a proprietary pipeline integrity monitoring method for managing pipe-lay operations. Technip has developed and tested this approach to optimise installation weather windows for the company’s reel-lay vessel, Apache. The method integrates both office-based analysis and offshore real-time motion monitoring. Limiting equations, which represent pipeline stresses and tensions during pipe-lay as a function of the motion of the pipeline top connection, are defined during pre-campaign finite element analysis. Considerable time savings are achieved over conventional approaches by utilising multi-parametric optimisation techniques. Once offshore, the actual motions are measured in real-time using a motion reference unit mounted on the lay ramp. Recorded data can then be compared against pre-defined multi-variate response surface. The system provides a real-time indication of the stress and tension levels in the pipeline. It is believed this method could introduce greater accuracy to pipeline integrity management in some circumstances, which in turn could provide more accurate information for making operational decisions. This novel approach is presented together with a description of current dynamic analysis philosophy and an alternative approach made possible by recent improvements in analytical software and computer processing capabilities.

Effects of grooved vanes on shock wave and forced response in a turbocharger turbine

2019 ◽  
pp. 146808741987926
Author(s):  
Ben Zhao ◽  
Xin Shi ◽  
Harold Sun ◽  
Mingxu Qi ◽  
Panpan Song
Keyword(s):  
Shock Wave ◽  
Numerical Method ◽  
High Cycle Fatigue ◽  
High Efficiency ◽  
Forced Response ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Turbine Wheel ◽  
Trade Off ◽  
Grooved Surface

In radial inflow turbine design, the optimization of turbine geometry for aerodynamic performance improvement is often constrained by the requirement of reliability, thus facing a trade-off. One of the vital challenges for a better trade-off is how to mitigate the forced response of turbine wheel, while maintaining high efficiency, so as to avoid high cycle fatigue failure. In this article, using a grooved surface on nozzle vanes for the forced response reduction was investigated. In light of the fact that the investigation on the high cycle fatigue issue involves both aerodynamic interactions and structural analyses, a customized computer code was developed using MATLAB software to couple computational fluid dynamics simulations with finite element analysis calculations. Partial results were compared against experimental results, respectively, to validate the numerical method. The coupled numerical method reveals that using the grooved surface on the nozzle vane alters the shock wave structure, decreases the peak stress of turbine wheel by 8%, and deteriorates turbine efficiency by 0.05 percentage points.

Finite Element Modeling for Steel Cord Analysis in Radial Tires

2013 ◽  
Vol 41 (1) ◽  
pp. 60-79 ◽  
Author(s):  
Wei Yintao ◽  
Luo Yiwen ◽  
Miao Yiming ◽  
Chai Delong ◽  
Feng Xijin
Keyword(s):  
Finite Element ◽  
High Efficiency ◽  
Force Measurement ◽  
Three Dimensional ◽  
Local Stress ◽  
Tension Force ◽  
Center Line ◽  
Element Analysis ◽  
Design Variables ◽  
Steel Cord

ABSTRACT: This article focuses on steel cord deformation and force investigation within heavy-duty radial tires. Typical bending deformation and tension force distributions of steel reinforcement within a truck bus radial (TBR) tire have been obtained, and they provide useful input for the local scale modeling of the steel cord. The three-dimensional carpet plots of the cord force distribution within a TBR tire are presented. The carcass-bending curvature is derived from the deformation of the carcass center line. A high-efficiency modeling approach for layered multistrand cord structures has been developed that uses cord design variables such as lay angle, lay length, and radius of the strand center line as input. Several types of steel cord have been modeled using the developed method as an example. The pure tension for two cords and the combined tension bending under various loading conditions relevant to tire deformation have been simulated by a finite element analysis (FEA). Good agreement has been found between experimental and FEA-determined tension force-displacement curves, and the characteristic structural and plastic deformation phases have been revealed by the FE simulation. Furthermore, some interesting local stress and deformation patterns under combined tension and bending are found that have not been previously reported. In addition, an experimental cord force measurement approach is included in this article.

Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems

1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Energy ◽  
Structural Integrity ◽  
Experimental Temperature ◽  
Temperature Profiles ◽  
Element Analysis ◽  
Drum Brake ◽  
Fea Model

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

scholarly journals Novel Approach Through the Harmonized Sulfur in Disordered Carbon Structure for High-Efficiency Sodium-Ion Exchange

2020 ◽  
Vol 12 (39) ◽  
pp. 43750-43760 ◽  
Author(s):  
Hanvin Kim ◽  
Dae-Yeong Kim ◽  
Shungo Zen ◽  
Jun Kang ◽  
Nozomi Takeuchi
Keyword(s):  
Ion Exchange ◽  
High Efficiency ◽  
Sodium Ion ◽  
Carbon Structure ◽  
Novel Approach ◽  
Disordered Carbon

scholarly journals Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Model Simulation ◽  
Analysis Tool ◽  
Overhead Line ◽  
Element Analysis ◽  
Novel Approach ◽  
Section Model ◽  
The Uk ◽  
Neutral Section

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

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