The Impact Damper Boring Bar and Its Performance When Cutting

1973 ◽  
pp. 47-51 ◽  
Author(s):  
M. D. Thomas ◽  
W. A. Knight ◽  
M. M. Sadek
Keyword(s):  
Impact Damper ◽  
Boring Bar ◽  
The Impact

The Impact Damper as a Method of Improving Cantilever Boring Bars

1975 ◽  
Vol 97 (3) ◽  
pp. 859-866 ◽  
Author(s):  
M. D. Thomas ◽  
W. A. Knight ◽  
M. M. Sadek
Keyword(s):  
Theoretical Analysis ◽  
Forced Vibration ◽  
Metal Removal ◽  
Mass Ratio ◽  
Impact Damper ◽  
Boring Bar ◽  
Improved Design ◽  
Vibration Tests ◽  
The Impact ◽  
Vibrating Systems

The dynamic behavior of three different designs of a cantilever boring bar are compared by means of forced vibration tests. These are a bar with diametrically opposed flats machined along its length, a bar fabricated from laminates of steel and a damping compound, and a bar fitted with an impact damper. The impact damper boring bar is found to be the most effective, and an improved design, giving increases in stable metal removal rates of more than 100 percent, is outlined and tested. A theoretical analysis is presented for predicting the effectiveness of the impact damper with a spring supported impacting mass. This analysis enables the optimum mass ratio and gap setting of the damper to be selected for specified characteristics of the vibrating systems to which the damper is fitted.

A Forced Response Analysis and Application of Impact Dampers to Rotordynamic Vibration Suppression in a Cryogenic Environment

1993 ◽  
Author(s):  
J. J. Moore ◽  
A. Palazzolo ◽  
R. Gadangi ◽  
T. A. Nale ◽  
S. A. Klusman ◽  
...  
Keyword(s):  
High Speed ◽  
Vibration Suppression ◽  
Forced Response ◽  
Optimum Operating ◽  
Response Analysis ◽  
Amplitude Dependence ◽  
Test Rig ◽  
Equivalent Viscous Damping ◽  
Impact Damper ◽  
The Impact

Abstract A high speed damper test rig has been assembled at Texas A&M University to develop rotordynamic dampers for rocket engine turbopumps that operate at cryogenic temperatures, such as those used in the Space Shuttle Main Engines (SSMEs). Damping is difficult to obtain in this class of turbomachinery due to the low temperature and viscosity of the operating fluid. An impact damper has been designed and tested as a means to obtain effective damping in a rotorbearing system. The performance and behavior of the impact damper is verified experimentally in a cryogenic test rig at Texas A&M. Analytical investigations indicate a strong amplitude dependence on the performance of the impact damper. An optimum operating amplitude exists and is determined both analytically and experimentally. In addition, the damper performance is characterized by an equivalent viscous damping coefficient. The test results prove the impact damper to be a viable means to suppress vibration in a cryogenic rotorbearing system.

Investigation into the linear velocity response of cantilever beam embedded with impact damper

2019 ◽  
Vol 25 (7) ◽  
pp. 1365-1378 ◽  
Author(s):  
Yiqing Yang ◽  
Xi Wang
Keyword(s):  
Cantilever Beam ◽  
Continuous System ◽  
Linear Velocity ◽  
Superposition Method ◽  
Momentum Exchange ◽  
Impact Damper ◽  
Mode Superposition Method ◽  
Velocity Response ◽  
The Impact ◽  
Nonlinear Velocity

The impact damper causes momentum exchange between the primary structure and impact mass, and achieves vibration attenuation through repeated collisions. A cantilever beam embedded with the impact damper is modeled in the form of a continuous system, and the equations of motion are formulated based on the mode superposition method. The mechanism of the impact damper is investigated, and linear velocity response is achieved by a proper selection of a mass ratio of 8.4%, clearance within 0.30 mm, and excitation force ranged from 3.2 N to 5.5 N. The reverse collision has higher damping than co-directional collision, based on which a new criterion of response regimes is proposed for the design of the impact damper. The velocity responses of the damped cantilever beam under sinusoidal and impulse excitation are simulated and verified via the sinusoidal sweep experiments. The velocity amplitudes of the damped cantilever beam are linearly decreased when the clearance is increased within 0.30 mm. Finally, linear and nonlinear velocity responses of the damped cantilever beam are discussed. It is found that the nonlinear velocity response reaches larger damping, but that a strongly modulated response exists.

Experimental Study of the Influence of Impact Mass on Damping Performance of Impact Dampers

2012 ◽  
Vol 246-247 ◽  
pp. 169-172
Author(s):  
Yan Zhu ◽  
Shi Shun Zhu ◽  
Wu Quan Liu ◽  
Shun Tang Hu
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Experimental Method ◽  
Total Mass ◽  
Resonance Region ◽  
Impact Damper ◽  
Damping Effect ◽  
Main System ◽  
The Impact ◽  
Impact Mass

We present a simulating experimental method used for studying the influence of impact mass on damping performance of impact dampers. The free mass in the impact damper had equal total mass but different size individual. We tested the damping effect of the damper under the same external force separately. The main results obtained in the experiments indicated that the impact damper had a good damping effect in the resonance region of the main system. The mass value of the free mass participating in vibro-impact was variable. In addition, the damping of the main system was related to the size of the free mass. In the conditions of equal total mass and same material, the size of the free mass was smaller, the effect of the vibration control was better.

The Effectiveness of the Impact Damper with a Spring-Supported Auxiliary Mass

1974 ◽  
Vol 16 (2) ◽  
pp. 109-116 ◽  
Author(s):  
M. D. Thomas ◽  
M. M. Sadek
Keyword(s):  
Spring Stiffness ◽  
Normal Impact ◽  
Impact Damper ◽  
Design Charts ◽  
Theoretical Predictions ◽  
Resonant Region ◽  
Frequency Ratios ◽  
The Impact ◽  
Impact Mass ◽  
Auxiliary Mass

This paper examines the effect of a spring-supported impact mass on the performance of an impact damper. This technique was developed after it was found that gravity detracts from the performance of a normal impact damper. The springs are used to support the impact mass at the mid point of its stroke so that the effect of gravity is negated. The analysis presented in this paper is based on the assumption that the motion of the impact mass is stable and that there are two impacts in each cycle. The assumption that the impacts are equi-spaced is not made, and it is shown that such behaviour occurs very rarely in the resonant region. Theoretical predictions are verified experimentally, and the analysis is then used to develop design charts for the impact damper at various damping ratios, mass ratios and gap ratios. It is shown that the spring is detrimental to the performance of the damper if gravity is not present, but that the performance under gravity is improved to that of the device without gravity. It is shown that very light supporting springs make the accuracy required in centring the impact mass too high, so that the performance in practice increases with spring stiffness. The performance of the device at natural frequency ratios greater than 0.5 is not studied.

Experimental study of passive vibration suppression using absorber with spherical ball impact damper

2016 ◽  
Vol 231 (17) ◽  
pp. 3193-3201 ◽  
Author(s):  
Riadh Chaari ◽  
Fathi Djemal ◽  
Fakher Chaari ◽  
Mohamed Slim Abbes ◽  
Mohamed Haddar
Keyword(s):  
Vibration Suppression ◽  
Industrial Applications ◽  
Design Parameters ◽  
Particle Impact ◽  
Ball Impact ◽  
Impact Damper ◽  
Ball Size ◽  
Wide Range ◽  
The Impact ◽  
Impact Damping

Impact dampers are efficient in many industrial applications with a wide range of frequencies. An experimental analysis of the impact damping of spherical balls is investigated to simplify the particle impact damping design and improve the vibration suppression. The objective of the study is to analyze some of the design parameters of impact damper using spherical balls. The experimental investigation consists to test the effect of the ball size for each mass level, the number of balls for each size level and different exciting force levels on vibrations of the main structure. The parametric study provided useful information to understand and optimize Particle Impact Damping design.

Effect of Gravity on the Performance of an Impact Damper: Part 2. Stability of Vibrational Modes

1970 ◽  
Vol 12 (4) ◽  
pp. 278-287 ◽  
Author(s):  
M. M. Sadek ◽  
C. J. H. Williams
Keyword(s):  
Vibrational Modes ◽  
Impact Damper ◽  
Main Mass ◽  
Modes Of Vibration ◽  
The Stability ◽  
The Impact

This paper is c oncerned with the stability of the various modes of vibration of the impact damper system described in Part 1†. Charts are presented showing the ranges of dynamically stable and kinematically viable periodic two-impact-per-cycle motion. The condition of kinematic viability ensures that the trajectory of the free mass remains within the container throughout the motion. It is shown that in general stable, viable, two-impact-per-cycle motion of the system exists under resonant conditions of the main mass and that away from resonance, where any damper is ineffective, this type of motion is generally unstable.

On the Stability of the Impact Damper

1966 ◽  
Vol 33 (3) ◽  
pp. 586-592 ◽  
Author(s):  
S. F. Masri ◽  
T. K. Caughey
Keyword(s):  
Exact Solution ◽  
Stability Analysis ◽  
Asymptotically Stable ◽  
Impact Damper ◽  
The Stability ◽  
The Impact

The exact solution for the symmetric two-impacts-per-cycle motion of the impact damper is derived analytically, and its asymptotically stable regions are determined. The stability analysis defines the zones where the modulus of all the eigenvalues of a certain matrix relating conditions after each of two consecutive impacts is less than unity.

Passive Multi-Degree-of-Freedom Structural Control Using LPC Impact Dampers

2015 ◽  
Author(s):  
Mohamed Gharib ◽  
Mansour Karkoub
Keyword(s):  
Structural Control ◽  
Flexible Structures ◽  
Tall Buildings ◽  
Degree Of Freedom ◽  
Frame Structure ◽  
Linear Arrangement ◽  
Impact Damper ◽  
Particle Chain ◽  
The Impact ◽  
Partial Damage

Excessive vibration is one of the main reasons leading to partial damage and in some cases collapse of tall buildings and structures. Impact dampers provide an effective, economical, and easy to install solution to the vibration problem in several applications. The latest developed type in the impact dampers family is the Linear Particle Chain (LPC) impact damper. It consists of a linear arrangement of two sizes of freely moving masses, constrained by two stops. This paper presents the results of an experimental investigation on the effectiveness of the LPC impact damper in damping the vibrations of a multi-degree-of-freedom system under different types of excitations. A prototype of the LPC impact dampers is fabricated and tested in our lab using a three-story frame structure. The experimental outcomes clearly show that the LPC impact damper can effectively attenuate the free and forced vibrations of flexible structures.

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