Lattice Brake Disc Instability Analysis Using Transient Complex Eigenvalue Method in Terms of Excitation Applied to the Pad

2018 ◽  
Author(s):  
AMINREZA KARAMOOZIAN ◽  
Chin Tan ◽  
liangmo Wang
Keyword(s):  
Brake Disc ◽  
Complex Eigenvalue ◽  
Instability Analysis ◽  
Transient Complex ◽  
Eigenvalue Method

Stability Improvement of Brake Disc to Mode Coupling at High Frequency Squeal

2020 ◽  
Author(s):  
Anutcharee Khuntiptong ◽  
Chak Chantalakhana
Keyword(s):  
Field Test ◽  
High Frequency ◽  
Element Model ◽  
Modal Testing ◽  
Brake Disc ◽  
Complex Eigenvalue ◽  
Brake Pads ◽  
Locking Mechanism ◽  
Out Of Plane ◽  
Complex Eigenvalue Analysis

In this research study, the high-frequency squeal noise of a brake disc was found to occurred at a frequency of about 15 kHz. The potential root cause has been studied where mode frequency coupling and shape locking mechanism of brake disc and brake pads components are the main investigated topic. From the vehicle field test and the Dynamometer test, the braking condition, friction coefficient and braking pressure, have been confirmed to be used in numerical experiments. The updated finite element model (FEM) with the modal testing data of the existing brake components are formulated for the Complex Eigenvalue Analysis (CEA). In this study, the modification is based on in-board and out-board cheek thickness of the brake disc. Two of nine modifications of the brake disc cheek thickness are proposed with the method of separation the brake disc out-of-plane and in-plane modes and the method of avoiding shape locking between the brake disc and the brake pads modes. The constructed prototypes are verified with the vehicle field test and well agreed with the CEA.

Friction-Induced, Self-Excited Vibration of a Pantograph-Catenary System

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
W. J. Qian ◽  
G. X. Chen ◽  
W. H. Zhang ◽  
H. Ouyang ◽  
Z. R. Zhou
Keyword(s):  
Friction Coefficient ◽  
Lift Force ◽  
Spatial Location ◽  
The Self ◽  
Complex Eigenvalue ◽  
Suspension Spring ◽  
Eigenvalue Method ◽  
Excited Vibration ◽  
The Coefficient Of Friction ◽  
Catenary System

A dynamic model of a pantograph-catenary system is established. In the model, motion of the pantograph is coupled with that of the catenary by friction. Stability of the pantograph-catenary system is studied using the finite element complex eigenvalue method. Numerical results show that there is a strong propensity of self-excited vibration of the pantograph-catenary system when the friction coefficient is greater than 0.1. The dynamic transient analysis results show that the self-excited vibration of the pantograph-catenary system can affect the contact condition between the pantograph and catenary. If the amplitude of the self-excited vibration is strong enough, the contact may even get lost. Parameter sensitivity analysis shows that the coefficient of friction, static lift force, pan-head suspension spring stiffness, tension of contact wire, and the spatial location of pantograph have important influences on the friction-induced, self-excited vibration of the pantograph-catenary system. Bringing the friction coefficient below a certain level and choosing a suitable static lift force can suppress or eliminate the contact loss between the pantograph and catenary.

An Instability Analysis Procedure for Three-Level Multi-Bearing Rotor-Foundation Systems

1998 ◽  
Vol 120 (3) ◽  
pp. 753-762 ◽  
Author(s):  
N. F. Rieger ◽  
S. Zhou
Keyword(s):  
System Model ◽  
Complex Eigenvalue ◽  
Rigid Rotor ◽  
Turbine Generator ◽  
Instability Analysis ◽  
Rotor Systems ◽  
Flexible Foundations ◽  
Threshold Conditions ◽  
Flexible Supports ◽  
The Stability

A procedure for the instability analysis of three-level multi-span rotor systems is described. This procedure is based on a distributed mass-elastic representation of the rotor system in several eight-coefficient bearings. Each bearing is supported from an elastic foundation on damped, elastic pedestals. The foundation is represented as a general distributed mass-elastic structure on discrete supports, which may have different stiffnesses and damping properties in the horizontal and vertical directions. This system model is suited to studies of instability threshold conditions for multi-rotor turbomachines on either massive or flexible foundations. The instability condition is found by obtaining the eigenvalues of the system determinant, which is obtained by the transfer matrix method from the three-level system model. The stability determinant is solved for the lowest rotational speed at which the system damping becomes zero in the complex eigenvalue, and for the whirl frequency corresponding to the natural frequency of the unstable mode. An efficient algorithm for achieving this is described. Application of this procedure to a rigid rotor in two damped-elastic bearings and flexible supports is described. Application of this procedure to a rigid rotor in two damped-elastic bearings and flexible supports is described. A second example discusses a flexible rotor with four damped-elastic bearings. The third case compares the stability of a six-bearing 300 Mw turbine generator unit, using two different bearing types. These applications validate the computer program and various aspects of the analysis.

Use of Constrained Viscoelastic Layers in the Design of Satellite Panels to Predict the Amplification Factor

2002 ◽  
Author(s):  
Marie-Jose´e Potvin ◽  
Andre´ Coˆte´ ◽  
Eric Charbonneau ◽  
Maria-Elena Aguilar
Keyword(s):  
Strain Energy ◽  
Amplification Factor ◽  
Complex Structure ◽  
Space Structure ◽  
Complex Eigenvalue ◽  
Critical Aspect ◽  
Element Analysis ◽  
Eigenvalue Method ◽  
Large Satellite ◽  
Viscoelastic Layers

A critical aspect of the design of a space structure is the prediction of the amplification factor. This factor is often estimated from comparison with similar structures, which can lead to costly errors. Adding viscoelastic patches enables an accurate prediction of the damping level of the structure since the viscoelastic patches become the main cause of damping for the structure. In this project, a test panel similar to large satellite feed panels is damped using five small viscoelastic patches. The location of the patches is optimized using the strain energy method. The amplification factor is obtained through a complex eigenvalue finite element analysis. The complex eigenvalue method is shown to be as accurate as the direct frequency analysis, but it runs much faster. The predicted amplification factor is within 15% of the experimental value which is a very good estimation for such a complex structure.

scholarly journals Dynamic Characteristics of Blade with Viscoelastic Damping Block Based on Complex Eigenvalue Method

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Jiao Wang ◽  
Yue-hao Zhang ◽  
Tao Yu ◽  
Qing-kai Han
Keyword(s):  
Differential Equations ◽  
Force Field ◽  
Natural Frequency ◽  
Dynamical Equation ◽  
Natural Frequencies ◽  
Damping Ratio ◽  
Constitutive Law ◽  
Viscoelastic Damping ◽  
Complex Eigenvalue ◽  
Eigenvalue Method

A novel method for vibration suppression is proposed, adding a viscoelastic damping block to the root of the blade. The dynamical equation for a rotational viscoelastic damping block-blade (VE-blade) in a centrifugal force field and aerodynamic force field is established to calculate the dynamical natural frequency and responses of the VE-blade. Complex modulus model is applied to represent the constitutive law of viscoelastic material and shear force acting on the VE-blade formulates the effect of viscoelastic damping at the root interfaces. The dynamical equation of the system is established and the Galerkin method is used to discretize the partial differential equations to a 3-DOF system so as to compute the dynamic natural frequencies and responses of the VE-blade. Then the differential equations of motion with 3-DOF are numerically solved by using complex eigenvalue method. A cantilever VE-blade is simplified according to testing the first three natural frequencies of the real blade to obtain geometric parameters of cantilever beam. The effects of various parameters including thickness, storage modulus, loss factor of viscoelastic damping block, and rotating speed on natural frequency and modal damping ratio of VE-blade are discussed in detail.

scholarly journals Study on the Different Effects of Power and Trailer Wheelsets on Wheel Polygonal Wear

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
X. N. Zhao ◽  
G. X. Chen ◽  
Z. Y. Huang ◽  
C. G. Xia
Keyword(s):  
Vibration Frequency ◽  
Complex Eigenvalue ◽  
Brake Pad ◽  
High Speeds ◽  
Eigenvalue Method ◽  
Excited Vibration ◽  
Creep Force ◽  
Polygonal Wear ◽  
Unstable Vibration ◽  
Development Tendency

The wheels of power and trailer wheelset show different polygonal characteristics since their structures are obviously different. Therefore, the frictional self-excited vibration models of wheelset-track systems are established based on the viewpoint of the frictional self-excited vibration in reducing the wheel polygonal wear. Then, the motion stability of wheelset-track systems is studied by using the complex eigenvalue method. The results show that when the creep force between the wheel and rail is saturated, the unstable vibration frequency of the power wheelset is prone to induce 19-20th-order polygonal wear of the wheel, and the trailer wheelset is prone to induce 20-21th-order polygonal wear of the wheel. Meanwhile, the wheel polygonal wear can be effectively alleviated through changing the gearbox position of the power wheelset. And avoiding disc braking at high speeds can suppress the occurrence of wheel polygonal wear. In addition, the development tendency of wheel polygonal wear can be reduced by increasing the Young’s modulus of the brake pad, but Poisson’s ratio has little effect on the development tendency.

Analysis of squeaking on ceramic hip endoprosthesis using the complex eigenvalue method

Wear ◽  
2011 ◽  
Vol 271 (9-10) ◽  
pp. 2305-2312 ◽  
Author(s):  
N. Fan ◽  
G.X. Chen ◽  
L.M. Qian
Keyword(s):  
Complex Eigenvalue ◽  
Hip Endoprosthesis ◽  
Eigenvalue Method

scholarly journals Impact Analysis of Brake Pad Backplate Structure and Friction Lining Material on Disc-Brake Noise

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Gongyu Pan ◽  
Lei Chen
Keyword(s):  
Layer Structure ◽  
Brake System ◽  
Mode Analysis ◽  
Bench Test ◽  
Brake Disc ◽  
Disc Brake ◽  
Complex Eigenvalue ◽  
Brake Pad ◽  
Six Dof ◽  
The Stability

This study proposes a three-layer brake pad design, on which a six-DOF dynamic model of brake disc-brake pad is established, and the factors affecting the system instability are analyzed. The analysis shows that the change of mass and stiffness of the brake pad will affect the stability of the system. From the linear complex eigenvalue analysis, the unstable vibration modes of the brake system are predicted, and the effectiveness of the complex mode analysis model is verified by the brake system bench test. Brake pads with different structural shapes are designed, and their influence on the stability of the brake system is analyzed. The results show that the design of the three-layer structure and the slotting design of the brake pad can effectively reduce the occurrence of the brake squeal, especially that of the high-frequency squeal noise.

Analysis of disc brake squeal using the complex eigenvalue method

2007 ◽  
Vol 68 (6) ◽  
pp. 603-615 ◽  
Author(s):  
P. Liu ◽  
H. Zheng ◽  
C. Cai ◽  
Y.Y. Wang ◽  
C. Lu ◽  
...  
Keyword(s):  
Disc Brake ◽  
Complex Eigenvalue ◽  
Brake Squeal ◽  
Eigenvalue Method
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