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.

On the Performance of Wave-Like Dry Friction and Piezoelectric Hybrid Flexible Dampers

2021 ◽  
Author(s):  
Y. G. Wu ◽  
Y. Fan ◽  
L. Li ◽  
Z. M. 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 (MHB-M). 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 wave-like 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.

Efficient Damping Prediction of Bolted Structures Using Harmonic Balance Method

2012 ◽  
Author(s):  
Pascal Reuss ◽  
Jens Becker ◽  
Lothar Gaul
Keyword(s):  
Harmonic Balance ◽  
Normal Force ◽  
Contact Stiffness ◽  
Harmonic Balance Method ◽  
Computation Time ◽  
Nonlinear Effects ◽  
Element Model ◽  
Balance Method ◽  
Friction Damper ◽  
Step Size

In this paper damping induced by extensive friction occurring in the interface between bolted structures is considered by simulations and experiments. A friction damper is attached to a beam-like flexible structure by screws such that the normal force in the interface can be varied by the clamping force of the screws. Contact and friction force parameters are identified by the comparison of simulated and experimentally determined FRFs for a particular normal force. Afterward a prediction of damping for different configurations is established. For simulations a finite element model is used where suitable contact and friction models are implemented. A time simulation of the system is expensive due to the large number of DoFs of the discretized substructures and the required small step size due to the high contact stiffness. Therefore model reduction methods are used. A further reduction of the computation time can be achieved by using the Harmonic Balance Method (HBM) for a direct frequency domain computation of FRFs. This enables an efficient procedure to approximate the reachable damping as well as to search the optimal damper position and the optimal normal force. The dependency of the friction to the vibration amplitude is therefore taken into account. A more detailed investigation of the nonlinear effects, e.g. higher harmonic response, is then accomplished by transient simulations for the optimal configured system in the time domain and the results are compared to experimental results.

Nonlinear Dynamics of Shrouded Turbine Blade System with Impact and Friction

2014 ◽  
Vol 706 ◽  
pp. 81-92 ◽  
Author(s):  
B. Santhosh ◽  
S. Narayanan ◽  
C. Padmanabhan
Keyword(s):  
Frequency Response ◽  
Turbine Blade ◽  
Dry Friction ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Tangential Direction ◽  
Stick Slip ◽  
Variable Friction ◽  
Blade System ◽  
Constant Normal Load

Dry friction dampers are passive devices used to reduce the resonant vibration amplitudes in turbine bladed systems. In shrouded turbine blade systems, in addition to the stick- slip motion induced by dry friction during the contact state in the tangential direction, the interface also undergoes intermittent separation in the normal direction. The problem can thus be treated as a combination of impact and friction. In this work, the dynamics of dry friction damped oscillators which are representative models of dry friction damped bladed system is investigated. A one dimensional contact model which is capable of modeling the interface under constant and variable normal load is used. The steady state periodic solutions are obtained by multi - harmonic balance method (MHBM). Frequency response plots are generated for different values of normal load using the arc length continuation procedure. The MHBM solutions are validated using numerical integration. A single degree of freedom (dof) model under constant normal load with constant and variable friction coefficients, a dry friction damped two dof system under constant normal load and a two dof system under variable normal load are investigated. In the presence of variable normal load, the system shows multivalued frequency response and jump phenomenon. The optimal value of the normal load which gives minimum resonant response is also obtained.

Forced Response of Shrouded Blades With Intermittent Dry Friction Force

2008 ◽  
Author(s):  
Weiwei Gu ◽  
Zili Xu ◽  
Lv Qiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Forced Response ◽  
Gap Size ◽  
Algebraic Equations ◽  
Friction Damper ◽  
Friction Forces ◽  
Contact Points

The gap friction damper model is presented in this paper, which is employed to simulate the friction forces at the contact points of the shroud interface. Using the harmonic balance method (HBM), the friction force can be approximated by a series of harmonic functions. The governing differential equations of blade motion are transformed into a set of nonlinear algebraic equations, which can be solved iteratively to yield the steady-state response. The results show that the forced response is attenuated due to the additional damping introduced by frictional slip. The predicted results agree well with those of the Runge-Kutta method. In addition, the effect of parameters of damping structures such as the gap size, friction coefficient and normal load on the forced response of blades were studied. The results show that increasing the damper gap size causes a increase in resonant response. However, the increment isn’t obvious. In addition, an increase in friction coefficient or normal load decreases the forced response of blade.

scholarly journals Design and Investigation of a Nonlinear Damper Based on Energy Dissipation through Shock and Dry Friction to Suppress Critical Self-Excited Vibrations in Drilling Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Vincent Kulke ◽  
Georg-Peter Ostermeyer ◽  
Andreas Hohl
Keyword(s):  
Energy Dissipation ◽  
Dry Friction ◽  
Harmonic Balance Method ◽  
Design Parameters ◽  
Drilling Process ◽  
Lumped Mass ◽  
Dissipation Energy ◽  
Rock Interaction ◽  
Reduced Order ◽  
Damping Effect

In this paper, a passive damper based on energy dissipation through shock and dry friction (shock-friction damper) is investigated regarding its design and effectiveness for damping self-excited torsional vibrations similar to those occurring in deep drilling. The results are compared to the results of conventional friction dampers. The effectiveness of the damper for different operational drilling parameters that change during the drilling process, such as the weight on the bit and the rotary speed of the bit, is analyzed. Two linear reduced order models of a drill string that are based on a complex finite element model are set up. One is reduced using the component mode synthesis and one is reduced to the identified critical mode. A lumped mass represents the inertia of a forcedly connected nonlinear damper. A combined reduced order model of the complex system and the inertia damper is introduced to investigate its dynamic motion and stability. Particular focus is on the energy flow within the dynamic system and on the change of the dissipation energy in the contact. A semi-analytical solution is derived using the harmonic balance method that is used to investigate the damping effect for various designs and operational parameters. Herein, the modal properties as well as parameters of the damper are examined regarding the damping effect and the stability of the system. Finally, the capability of the mechanism to suppress the self-excitation due to the bit–rock interaction in a drilling system is discussed, and recommendations are made with respect to the design parameters and placement of the damper.

scholarly journals Computation of the Optimal Normal Load of a Friction Damper Under Different Types of Excitation

1999 ◽  
Author(s):  
D. Cha ◽  
A. Sinha
Keyword(s):  
White Noise ◽  
Narrow Band ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Random Excitation ◽  
Linearization Method ◽  
Equivalent Linearization ◽  
Friction Damper ◽  
Different Types ◽  
Sinusoidal Excitation

In this paper, forced responses of a frictionally damped turbine blade are investigated for three different types of excitation: white noise excitation, narrow band random excitation and deterministic sinusoidal excitation. To determine the steady state nonlinear response, the harmonic balance method is used for sinusoidal excitation, and the equivalent linearization method is used for white noise and narrow band random excitations. Using a new set of nondimensionalized variables, the optimal value of normal load of a friction damper is found to be almost independent of the nature of excitation. The effectiveness of the damper in reducing the vibration level is also examined for the aforementioned three different types of excitation.

Theoretical Dynamic Analysis of a Cantilever Beam Damped by a Dry Friction Damper

1995 ◽  
Author(s):  
I. Korkmaz ◽  
J. J. Barrau ◽  
M. Berthillier ◽  
S. Creze
Keyword(s):  
Dynamic Response ◽  
Cantilever Beam ◽  
Dry Friction ◽  
Coulomb Friction ◽  
Contact Stiffness ◽  
Temporal Integration ◽  
Element Model ◽  
Friction Damper ◽  
Coulomb Friction Law ◽  
Good Agreement

Abstract The dynamic behavior of a cantilever beam damped by dry friction has been studied The beam is represented partly by its effective modal parameters, obtained from a finite element model. The Coulomb friction law is used and a temporal integration of the dynamic response is performed. A detailed parametric study, highlighting the influence of the static and the dynamic friction coefficients, the viscous damping coefficient, the contact stiffness and the position of the damper along the span, on the dynamic response has been conducted. A better understanding of the damping mechanism by dry friction has been obtained. The numerical results have been compared to experimental results, and a good agreement was found. The results could be applied to a turbine blade with a blade to ground damper.

Computation of the Optimal Normal Load of a Friction Damper Under Different Types of Excitation

2003 ◽  
Vol 125 (4) ◽  
pp. 1042-1049 ◽  
Author(s):  
D. Cha ◽  
A. Sinha
Keyword(s):  
White Noise ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Random Excitation ◽  
Linearization Method ◽  
Equivalent Linearization ◽  
Friction Damper ◽  
Different Types ◽  
Forced Responses ◽  
Sinusoidal Excitation

In this paper, forced responses of a frictionally damped turbine blade are investigated for three different types of excitation: white noise excitation, narrowband random excitation, and deterministic sinusoidal excitation. To determine the steady-state nonlinear response, the harmonic balance method is used for sinusoidal excitation, and the equivalent linearization method is used for white noise and narrowband random excitations. Using a new set of nondimensionalized variables, the optimal value of normal load of a friction damper is found to be almost independent of the nature of excitation. The effectiveness of the damper in reducing the vibration level is also examined for the aforementioned three different types of excitation.

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.

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