scholarly journals Dynamic Characteristics of a Segmented Supercritical Driveline with Flexible Couplings and Dry Friction Dampers

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 281
Author(s):  
Zhonghe Huang ◽  
Jianping Tan ◽  
Chuliang Liu ◽  
Xiong Lu
Keyword(s):  
Dry Friction ◽  
Vibration Suppression ◽  
Parameter Analysis ◽  
Friction Damper ◽  
Dynamic Effects ◽  
Angular Misalignment ◽  
Friction Dampers ◽  
Response Characteristics ◽  
Flexible Diaphragm ◽  
Simulation And Experiment

Helicopter tail rotors adopt a segmented driveline connected by flexible couplings, and dry friction dampers to suppress resonance. Modeling for this system can provide a basic foundation for parameter analysis. In this work, the lateral-torsional vibration equation of the shaft with continuous internal damping is established. The static and dynamic effects caused by flexible diaphragm couplings subject to parallel and angular misalignment is derived. A novel dual rub-impact model between the shaft and dry friction damper with multiple stages is proposed. Finally, a model of a helicopter tail rotor driveline incorporating all the above elements is formulated. Numerical simulations are carried out by an improved Adams–Bashforth method following the design flowchart. The dynamics of multiple vibration suppression, and the static and dynamic misalignment are analyzed to illustrate the accuracy and characteristics of the model. The coeffect of the rub impact and the misalignment on shafts and dampers are presented through the results of simulation and experiment. It provides an accurate and comprehensive mathematical model for the helicopter driveline. Response characteristics of multiple damping stages, static and dynamic misalignment, and their interaction are revealed.

scholarly journals Improved Reliability of Bladed Disks due to Friction Dampers

1997 ◽  
Author(s):  
Walter Sextro ◽  
Karl Popp ◽  
Ivo Wolter
Keyword(s):  
Dry Friction ◽  
Three Dimensional ◽  
Line Contact ◽  
Two Dimensional ◽  
Centrifugal Forces ◽  
Friction Damper ◽  
Blade Vibration ◽  
Friction Dampers ◽  
Bladed Disk ◽  
Bladed Disk Assembly

Friction dampers are installed underneath the blade platforms to improve the reliability. Because of centrifugal forces the dampers are pressed onto the platforms. Due to dry friction and the relative motion between blades and dampers, energy is dissipated, which results in a reduction of blade vibration amplitudes. The geometry of the contact is in many cases like a Hertzian line contact. A three-dimensional motion of the blades results in a two-dimensional motion of one contact line of the friction dampers in the contact plane. An experiment with one friction damper between two blades is used to verify the two-dimensional contact model including microslip. By optimizing the friction dampers masses, the best damping effects are obtained. Finally, different methods are shown to calculate the envelope of a three-dimensional response of a detuned bladed disk assembly (V84.3-4th-stage turbine blade) with friction dampers.

Friction Dampers: Measurement, Modelling and Application to Blade Vibration Control

1995 ◽  
Author(s):  
Kenan Y. Sanliturk ◽  
Anthony B. Stanbridge ◽  
David J. Ewins
Keyword(s):  
Harmonic Balance Method ◽  
Theoretical Modelling ◽  
Dynamic Force ◽  
Friction Damper ◽  
Blade Vibration ◽  
Friction Dampers ◽  
Response Characteristics ◽  
Joint Characteristics ◽  
Contact Behaviour ◽  
Better Than

Abstract This paper describes a procedure that combines the measurement of dry-friction contact behaviour, its theoretical modelling and the analysis of structures with friction joints. The experimental part describes a friction damper test rig which is specifically designed for measuring the dynamic force-response characteristics of a joint. A hybrid mathematical model, which is a combination of the traditional macro- and micro-slip models, is proposed to represent the joint characteristics and it is shown that such a model represents the measured behaviour better than any of the traditional ones. The final part of the paper demonstrates the procedure applied to a blade-damper test structure and which includes testing, analysis and correlation of both sets of results. The non-linear response levels are predicted using a dedicated program based on the Harmonic Balance Method and it is found that the proposed analysis procedure can predict the amount of response reduction, the optimum friction damper load and the locked natural frequency quite accurately.

Blades Forced Response Analysis With Friction Dampers

1998 ◽  
Vol 120 (2) ◽  
pp. 468-474 ◽  
Author(s):  
M. Berthillier ◽  
C. Dupont ◽  
R. Mondal ◽  
J. J. Barrau
Keyword(s):  
Time Domain ◽  
Dry Friction ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Forced Response ◽  
Response Analysis ◽  
Friction Damper ◽  
Friction Dampers ◽  
Fan Blade

A multiharmonic frequency domain analysis combined with a Craig-Bampton component mode synthesis is presented to compute the dry friction damped forced response of blades. The accuracy of the analysis is established, for a cantilever beam with a dry friction damper attached, by comparison with experimental results and time domain analysis. The method has then been applied to a model fan blade damped by a blade to ground damper.

scholarly journals A Hybrid Nonlinear Active Control Strategy Combining Dry Friction Control and Nonlinear Velocity Compensation Control

2021 ◽  
Vol 11 (24) ◽  
pp. 11670
Author(s):  
Donglai Yang ◽  
Xingrong Huang ◽  
Xiaodong Yang
Keyword(s):  
Active Control ◽  
Friction Force ◽  
Control Strategy ◽  
Dry Friction ◽  
Vibration Suppression ◽  
Hybrid Control ◽  
Control Law ◽  
Control Force ◽  
Friction Dampers ◽  
Nonlinear Velocity

Friction dampers are widely used in structural vibration suppression in various fields, such as aeronautics, astronautics, robotics, precision manufacturing, etc. Traditional friction dampers are mainly used in a passive way to optimize vibration suppression with an immutable pressure around certain excitation. In this manuscript, a hybrid control strategy by considering both the friction force in the active control law and a nonlinear velocity compensation force is put forward: First, the normal force applied on the friction damper was adjusted to ensure its vibration reduction effect under different excitation for a first passive control; second, the active control law was established by combining the dry friction force and the velocity control force in the state space; lastly, the stability of the nonlinear control law was determined by Lyapunov criterion. Numerical simulations were conducted on a three degree-of-freedom system (3-DOF) based on the proposed hybrid control strategy, to show the control efficiency in vibration suppression and economic efficiency in energy input into the system. Simulation results showed that the proposed control law could reduce the amplitude of the active control force by about 5% without degrading the control efficiency.

Seismic performance evaluation of multi-story CBFs equipped with SMA-friction damping braces

2021 ◽  
pp. 1045389X2098700 ◽  
Author(s):  
Canxing Qiu ◽  
Jiawang Liu ◽  
Jun Teng ◽  
Zuohua Li ◽  
Xiuli Du
Keyword(s):  
Strain Hardening ◽  
Ground Motions ◽  
Residual Deformation ◽  
Martensite Phase ◽  
Friction Damper ◽  
Concentrically Braced Frames ◽  
Friction Damping ◽  
Friction Mechanism ◽  
Building Collapse ◽  
Response Characteristics

Shape memory alloys (SMAs) gained increasing attentions from the perspective of seismic protection, primarily because of their excellent superelasticity, satisfactory damping and high fatigue life. However, the superelastic strain of SMAs has an upper limit, beyond which the material completes the austenite to martensite phase transformation and is followed by noticeable strain hardening. The strain hardening behavior would not only induce high force demand to the protected structures, but also cause unrecoverable deformation. More importantly, the SMAs may fracture if the deformation demand exceeds their capacity under severe earthquakes. In the case of installing SMA braces (SMABs) in the multi-story concentrically braced frames (CBFs), the material failure would lead to the malfunction of SMABs and this further causes building collapse. The friction mechanism could behave as a “fuse” through capping the strength demand at a constant level. Therefore, this paper suggests connecting the SMAB with a friction damper to achieve a novel brace, i.e. the SMA-friction damping brace (SMAFDB). A proof-of-concept test was carried out on a homemade specimen and the test results validated the novel brace behaves in a desirable manner. In addition, to explore the seismic response characteristics of the SMAFDB within structures, a six-story CBF equipped with SMAFDBs was designed and compared against those incorporated with SMABs or friction damping braces (FDBs) at the frequently occurred earthquake (FOE), design basis earthquake (DBE) and maximum considered earthquake (MCE). The comparative results show the SMAFDB is superior to the counterparts. Under the FOE and DBE ground motions, the SMAFDBs successfully eliminated residual deformations as the SMABs do, and achieved identical maximum interstory drift as the FDBs. Under the MCE ground motions, the SMAFDBs not only well addressed the brace failure problem that was possibly encountered in the SMABs, but also better controlled residual deformation than the FDBs.

Research on Damping Vibration Reduction Design Method of Aeroengine Supporting Structure System

2020 ◽  
Author(s):  
Chao Li ◽  
Binglong Lei ◽  
Yanhong Ma ◽  
Jie Hong
Keyword(s):  
Dry Friction ◽  
Dynamic Stiffness ◽  
Vibration Reduction ◽  
Vibration Response ◽  
Contact Friction ◽  
Friction Damper ◽  
Support Structure ◽  
Response Control ◽  
Structure System ◽  
Supporting Structure

Abstract Typical turbofan engine-support-structure systems having a high thrust-to-weight ratio are light, and the structure primarily comprises a plate and shells. The local vibration response of the support structure is excessively large when different frequency loads are applied. A structural vibration response control method based on dry friction damping is proposed to control the excessive vibration response. A dry friction damper with dynamic suction was designed to enhance the damping characteristics of the rotor supporting structure system in the wide frequency domain, without sacrificing the dynamic stiffness of the structure. The system is designed to effectively control the vibration response of the supporting structure at the working-speed frequency. Through theoretical modeling and simulation analyses, the influence of friction contact and damper structure characteristics on the damping effect is described quantitatively. Furthermore, the design idea and the damping process of the supporting structure are described. The calculation results show that the contact friction of the dry friction damper can consume the vibration energy of the supporting frame. A reasonable design of the contact characteristics and geometric configuration parameters of the damper can further optimize the vibration-reduction effect, and thereby improve the vibration response control design of the supporting structure system of aeroengines.

On the Performance of Wavy Dry Friction and Piezoelectric Hybrid Flexible Dampers

2021 ◽  
Author(s):  
Yaguang Wu ◽  
Yu Fan ◽  
Lin Li ◽  
Zhimei Zhao
Keyword(s):  
Piezoelectric Material ◽  
Dry Friction ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Element Model ◽  
Total Output ◽  
Friction Damper ◽  
Damping Effect ◽  
Thin Walled Structures ◽  
Friction Plate

Abstract This paper proposes a flexible dry friction plate to mitigate the vibration of thin-walled structures for one resonance crossing. Based on a cantilever beam-friction damper finite element model, the geometry and material parameters of the friction plate are optimized numerically through steady-state response analyses by the widely-used Multi-Harmonic Balance Method (MHBM). In order to further improve the damping effect, piezoelectric material is distributed to the flexible damper, and two types of dry friction and piezoelectric hybrid dampers are explored, namely semi-active and passive, respectively. For semi-active hybrid dampers, piezoelectric material is used as an actuator to adjust the normal load applied to the friction interface in real time, so that the friction damping is improved. For passive ones, piezoelectric material is used as a transducer, which dissipates the strain energy stored in the wavy plate by the shunting circuit, additional shunted piezoelectric damping contributes to the total output damping accordingly. Better damping effect compared with the friction baseline is realized for the two types ideally. This damping module has a simple structure and avoids the problem of installation and maintenance of piezoelectric material which is generally bonded to the host structure. Technical challenges are: the semi-active type requires excessive voltage applied to the piezoelectric actuator, while the passive one needs to connect a programmable synthetic circuit.

scholarly journals Friction Damper Optimisation: Simulation of Rainbow Tests

1999 ◽  
Author(s):  
Kenan Y. Sanliturk ◽  
David J. Ewins ◽  
Robert Elliott ◽  
Jeff S. Green
Keyword(s):  
Harmonic Balance Method ◽  
Lumped Parameter Model ◽  
Friction Damper ◽  
Blade Vibration ◽  
Friction Dampers ◽  
Lumped Parameter ◽  
Engine Order ◽  
Resonance Response ◽  
Theoretical Predictions ◽  
Different Characteristics

Friction dampers have been used to reduce turbine blade vibration levels for a considerable period of time. However, optimal design of these dampers has been quite difficult due both to a lack of adequate theoretical predictions and to difficulties in conducting reliable experiments. One of the difficulties of damper weight optimisation via the experimental route has been the inevitable effects of mistuning. Also, conducting separate experiments for different damper weights involves excessive cost. Therefore, current practice in the turbomachinery industry has been to conduct so-called ‘rainbow tests’ where friction dampers with different weights are placed between blades with a predefined configuration. However, it has been observed that some rainbow test results have been difficult to interpret and have been inconclusive for determining the optimum damper weight for a given bladed-disc assembly. A new method of analysis — a combination of Harmonic Balance Method and structural modification approaches — is presented in this paper for the analysis of structures with friction interfaces and the method is applied to search for qualitative answers about the so-called ‘rainbow tests’ in turbomachinery applications. A simple lumped-parameter model of a bladed-disc model was used and different damper weights were modelled using friction elements with different characteristics. Resonance response levels were obtained for bladed discs with various numbers of blades under various engine-order excitations. It was found that rainbow tests, where friction dampers with different weights are used on the same bladed-disc assembly, can be used to find the optimum damper weight if the mode of vibration concerned has weak blade-to-blade coupling (the case where the disc is almost rigid and blades vibrate almost independently from each other). Otherwise, it is very difficult to draw any reliable conclusion from such expensive experiments.

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