A Friction-Enhanced Tuned Ring Damper for Bladed Disks

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Andrea Lupini ◽  
Bogdan I. Epureanu
Keyword(s):  
Energy Transfer ◽  
Relative Motion ◽  
Natural Frequencies ◽  
Complex Geometry ◽  
High Fidelity ◽  
Frictional Contacts ◽  
New Type ◽  
Frictional Interface ◽  
Host Structure ◽  
Tuned Vibration Absorber

Abstract This paper introduces a new type of damper for turbomachinery blisks. The major pitfalls of the damper concepts currently employed are two: the low level of relative motion that is available at the damper attachment location, and the inability to control the preload at the frictional interface. To address these issues, the proposed damper is designed as a tuned vibration absorber (TVA), which allows energy transfer from the blades to the damper provided that the natural frequency of the damper is close to that of the host structure. Thanks to the enhanced energy transfer, the damper can experience increased relative motion. Frictional contacts are then included to dissipate the energy transferred to the damper. The damper structure must be stiff enough to withstand centrifugal loading without affecting the preload too much. However, it also must be compliant to make sure that its natural frequencies can match the ones of the host structure. For this reason, the proposed damper involves a complex geometry that is stiff in the radial direction and softer in the circumferential direction, which is the direction of the relative motion. A model of the damper is created to damp the vibration of a realistic blisk. The effectiveness of the damper is investigated using high fidelity finite element (FE) models. The frequency response of the system is obtained to analyze the effectiveness of the proposed design. Preliminary results show the potential of this technology for structures with such low damping.

A Friction-Enhanced Tuned Ring Damper for Bladed Disks

2020 ◽  
Author(s):  
Andrea Lupini ◽  
Bogdan I. Epureanu
Keyword(s):  
Energy Transfer ◽  
Relative Motion ◽  
Complex Geometry ◽  
Equations Of Motion ◽  
Linear Part ◽  
Frictional Contacts ◽  
New Type ◽  
Frictional Interface ◽  
Host Structure ◽  
Competing Priorities

Abstract This paper introduces a new type of damper for turbomachinery blisks. The major pitfalls of the damper concepts currently employed are two: the low level of relative motion that is available at the damper attachment location, and the inability to control the preload at the frictional interface. To address these issues, the proposed damper is designed as a tuned vibration absorber, which allows energy transfer from the blades to the damper provided that the natural frequency of the damper is close to that of the host structure. Thanks to the enhanced energy transfer, the damper can experience increased relative motion. Frictional contacts are then included to dissipate the energy transferred to the damper. The control of the contact preload is also important, as the centrifugal loads acting on the damper are extremely large and could result in the damper being stuck in its groove and not dissipating energy. These two requirements result in competing priorities. The damper structure must be stiff enough to withstand centrifugal loading without affecting the preload too much. However, it also must be compliant to make sure that its natural frequencies can match the ones of the host structure. For this reason, the proposed damper involves a complex geometry that is stiff in the radial direction and softer in the circumferential direction, which is the direction of the relative motion. A model of the damper is created to damp the vibration of a realistic blisk based on the NASA Rotor 67. The effectiveness of the damper is investigated using high fidelity finite element models. Due to the nonlinear nature of the contact, the equations of motion are solved using harmonic balance, and the size of the (linear part of the) system is reduced using Craig-Bampton component mode synthesis. The frequency response of the system is obtained to analyze the effectiveness of the proposed design. Preliminary results show the potential of this technology for structures with such low damping.

scholarly journals Sodium Metasilicate Cemented Analogue Material and Its Mechanical Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Songlin Yue ◽  
Yanyu Qiu ◽  
Pengxian Fan ◽  
Pin Zhang ◽  
Ning Zhang
Keyword(s):  
Complex Geometry ◽  
Sodium Metasilicate ◽  
Raw Material ◽  
Fine Aggregate ◽  
Regression Equations ◽  
Deformation And Failure ◽  
Orthogonal Experiments ◽  
Low Modulus ◽  
New Type ◽  
The Relationship

Analogue material with appropriate properties is of great importance to the reliability of geomechanical model test, which is one of the mostly used approaches in field of geotechnical research. In this paper, a new type of analogue material is developed, which is composed of coarse aggregate (quartz sand and/or barite sand), fine aggregate (barite powder), and cementitious material (anhydrous sodium silicate). The components of each raw material are the key influencing factors, which significantly affect the physical and mechanical parameters of analogue materials. In order to establish the relationship between parameters and factors, the material properties including density, Young’s modulus, uniaxial compressive strength, and tensile strength were investigated by a series of orthogonal experiments with hundreds of samples. By orthogonal regression analysis, the regression equations of each parameter were obtained based on experimental data, which can predict the properties of the developed analogue materials according to proportions. The experiments and applications indicate that sodium metasilicate cemented analogue material is a type of low-strength and low-modulus material with designable density, which is insensitive to humidity and temperature and satisfies mechanical scaling criteria for weak rock or soft geological materials. Moreover, the developed material can be easily cast into structures with complex geometry shapes and simulate the deformation and failure processes of prototype rocks.

Fully Parametric High-Fidelity CFD Model for the Design Optimisation of the Cyclic Stagger Pattern of a Set of Fan Outlet Guide Vanes

2009 ◽  
Author(s):  
Andrea Milli ◽  
Olivier Bron
Keyword(s):  
Complex Geometry ◽  
Single Point ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
High Fidelity ◽  
Cfd Model ◽  
Design Optimisation ◽  
Guide Vanes ◽  
High Loss ◽  
Design Variables

The present paper deals with the redesign of cyclic variation of a set of fan outlet guide vanes by means of high-fidelity full-annulus CFD. The necessity for the aerodynamic redesign originated from a change to the original project requirement, when the customer requested an increase in specific thrust above the original engine specification. The main objectives of this paper are: 1) make use of 3D CFD simulations to accurately model the flow field and identify high-loss regions; 2) elaborate an effective optimisation strategy using engineering judgement in order to define realistic objectives, constraints and design variables; 3) emphasise the importance of parametric geometry modelling and meshing for automatic design optimisation of complex turbomachinery configurations; 4) illustrate that the combination of advanced optimisation algorithms and aerodynamic expertise can lead to successful optimisations of complex turbomachinery components within practical time and costs constrains. The current design optimisation exercise was carried out using an in-house set of software tools to mesh, resolve, analyse and optimise turbomachinery components by means of Reynolds-averaged Navier-Stokes simulations. The original configuration was analysed using the 3D CFD model and thereafter assessed against experimental data and flow visualisations. The main objective of this phase was to acquire a deep insight of the aerodynamics and the loss mechanisms. This was important to appropriately limit the design scope and to drive the optimisation in the desirable direction with a limited number of design variables. A mesh sensitivity study was performed in order to minimise computational costs. Partially converged CFD solutions with restart and response surface models were used to speed up the optimisation loop. Finally, the single-point optimised circumferential stagger pattern was manually adjusted to increase the robustness of the design at other flight operating conditions. Overall, the optimisation resulted in a major loss reduction and increased operating range. Most important, it provided the project with an alternative and improved design within the time schedule requested and demonstrated that CFD tools can be used effectively not only for the analysis but also to provide new design solutions as a matter of routine even for very complex geometry configurations.

Detecting Loosening of Bolted Connections in a Pipeline Using Changes in Natural Frequencies

2011 ◽  
Author(s):  
K. He ◽  
W. D. Zhu
Keyword(s):  
Damage Detection ◽  
Natural Frequencies ◽  
Detection Method ◽  
Complex Geometry ◽  
Early Stage ◽  
Measurement Noise ◽  
Modeling Error ◽  
Bolted Connections ◽  
Bolted Connection ◽  
Stiffness Reduction

Loosening of bolted connections in a structure can significantly reduce the load-bearing capacities of the structure. Detecting loosening of bolted connections at an early stage can avoid failure of the structure. Due to the complex geometry of a bolted connection and the material discontinuity between the clamped components, it is difficult to detect loosening of a bolted connection using conventional non-destructive test methods. A vibration-based method that uses changes in natural frequencies of a structure to detect the locations and extent of damage can be used to detect loosening of bolted connections, since the method focuses on detecting a stiffness reduction, which can result from loosening of the bolted connections. Experimental and numerical damage detection using the vibration-based method was conducted to detect the loosening of the bolted connections in a fullsize steel pipeline with bolted flanges. With the recent development of a predictive modeling technique for bolted connections in thin-walled structures, an accurate physics-based finite element model of the pipeline that is required by the vibration-based damage detection method is developed. A trust-region search strategy is employed to improve the damage detection method so that convergence of the damage detection algorithm can be ensured for under-determined systems, and the robustness of the algorithm can be enhanced when relatively large modeling error and measurement noise are present. The location and extent of the loosened bolted connections were successfully detected in experimental damage detection using changes in the natural frequencies of the first several modes; the exact location and extent of the loosened bolted connections can be detected in the numerical simulation where there are no modeling error and measurement noise.

A new type of triphenylamine based coumarin–rhodamine hybrid compound: synthesis, photophysical properties, viscosity sensitivity and energy transfer

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105387-105397 ◽  
Author(s):  
Shantaram Kothavale ◽  
Nagaiyan Sekar
Keyword(s):  
Energy Transfer ◽  
Phenyl Ring ◽  
Photophysical Properties ◽  
The Other ◽  
Hybrid Compound ◽  
Compound Synthesis ◽  
New Type ◽  
Molecular Skeleton

A series of novel core modified triphenylamine coumarin–rhodamine systems (compounds MCMR, MCDR and DCMR) was designed and synthesized by incorporating a coumarin moiety on one and a rhodamine moiety on the other phenyl ring of the triphenylamine molecular skeleton.

A New Type of X-Ray Diffractometer with Cooperating Robots for Residual Stress Analysis on Large Components

2006 ◽  
Vol 524-525 ◽  
pp. 749-754 ◽  
Author(s):  
Roland Hessert ◽  
Wilhelm Satzger ◽  
Alfried Haase ◽  
Achim Schafmeister
Keyword(s):  
Complex Geometry ◽  
Industrial Applications ◽  
Measuring System ◽  
X Ray ◽  
Material Condition ◽  
New Type ◽  
Cooperating Robots ◽  
Aero Engines ◽  
Reference Measurements ◽  
Engine Components

For industrial applications concerning the nondestructive characterization of the nearsurface material condition in terms of residual stresses, work hardening, phase transformation and formation of reaction compounds there is a strong demand for X-ray diffraction measurements on large components with complex geometry. Because many regions of interest on these components are not accessible with conventional laboratory or even mobile X-ray diffractometers, a novel center- free diffractometer with two cooperating robots named "Charon XRD" has been developed at MTU Aero Engines. Using a special optical measuring system to synchronize the two six-axis robots it was possible to achieve positioning accuracies that are comparable to those of conventional stationary diffractometers. This paper describes the design and functionality of Charon XRD and presents calibration and reference measurements, along with first measurements on aero-engine components.

Research on Dynamic Characteristics for Large Span Cable-Stayed Suspension Bridges with CFRP Cables

2013 ◽  
Vol 683 ◽  
pp. 845-850
Author(s):  
Rong Gui Liu ◽  
Guo Ying Feng ◽  
Bei Chen
Keyword(s):  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Natural Frequencies ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Bridge Structure ◽  
Reinforced Plastics ◽  
New Type ◽  
Carbon Fibre Reinforced Plastics ◽  
Cable Stayed Bridges

Cable-stayed suspension bridge with Carbon Fibre Reinforced Plastics(CFRP) cables is a new type of bridge structure. To study the dynamic characteristics for this kind of bridges, and its differences from cable-stayed bridges of the same span level, finite element dynamic modle of a Cable-stayed suspension bridge with main span of 1488 meters is established and a series of calculations is done. The results show that, natural frequencies of cable-stayed suspension bridges with CFRP cables are relatively small, integral frequencies are stepped and discontinuous; Its modes are centralized and the natural vibration modes show a lot of coupling; The natural frequencies of this kind of bridges are smaller than cable-stayed bridges of the same span level, the entire stiffness decreased.

A New Type of NES: Rotary Vibro-Impact

2017 ◽  
Author(s):  
Adnan S. Saeed ◽  
Mohammad A. AL-Shudeifat
Keyword(s):  
Energy Transfer ◽  
Energy Dissipation ◽  
Physical System ◽  
High Energy ◽  
Primary System ◽  
Targeted Energy Transfer ◽  
New Type ◽  
High Energy Dissipation ◽  
Nonlinear Energy ◽  
Promising Type

Rotating and vibro-impact Nonlinear Energy Sinks (NESs) have been employed for rapid and passive Targeted Energy Transfer (TET). Both have been proven to be efficient, shown high energy dissipation and have been tested experimentally. A novel type of NES that combines the two principles of nonlinear TET, rotating inertial coupling and vibro-impact, is numerically investigated on a 2 degree of freedom physical system. Two configurations of the new promising NES are considered via changing the location of the impacts. The optimized parameters of both configurations proved that high amounts of energy can be transferred from the primary system to the new promising type of NESs passively and rapidly.

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