Vibration Suppression in a Cantilever Beam Using a String-Type Vibration Absorber

Author(s):  
Jimmy S. Issa ◽  
Wassim F. Habchi

A string-type vibration absorber is proposed to suppress energy from a vibrating beam. A cantilever beam is considered with a harmonic force applied at its free end. The vibration absorber is a string attached to the beam at two different points. The string is rigidly connected to the fixed end of the beam and through a spring and damper to a second point on the beam. The finite element method is used to model the system and a reduced order model is obtained through modal reduction performed on both the string and the beam. The steady state amplitude of the transverse vibration of the beam is calculated using the first two modes of the beam-string system. It is found that the maximum amplitude at a given point of the beam occurs at a forcing frequency which is a root of a sixth order polynomial. The design of the vibration absorber is done in two steps. In the first, the spring stiffness, the position of the second attachment point of the string and a preliminary damping constant are calculated using a genetic algorithm approach where the objective function is the maximum displacement on the beam. Fine tuning is done in the second optimization step, by choosing an appropriate damping constant to further improve the design. To avoid buckling, the string tension is set to a value less than the lowest buckling force of the system. Numerical simulations of the beam’s maximum amplitude with and without absorber are shown to validate the proposed design.

2021 ◽  
pp. 107754632110144
Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Qiang Liu

Turning cutting tool with large length–diameter ratio has been essential when machining structural part with deep cavity and in-depth hole features. However, chatter vibration is apt to occur with the increase of tool overhang. A slender turning cutting tool with a length–diameter ratio of 7 is developed by using a vibration absorber equipped with piezoelectric ceramic. The vibration absorber has dual functions of vibration transfer to the absorber mass and vibration conversion to the electrical energy via the piezoelectric effect. Equations of motion are established considering the dual damping from the piezoelectric ceramic and rubber gasket. The equivalent damping of piezoelectric ceramic is derived, and the geometries are optimized to achieve optimal vibration suppression. The modal analysis demonstrates that the cutting tool with the vibration absorber can reach 80.1% magnitude reduction. Machining tests are carried out in the end. The machining acceleration and machined surface roughness validate the vibration suppression of the VA, and the output voltage by the piezoelectric ceramic demonstrates the ability of vibration sensing.


2013 ◽  
Vol 300-301 ◽  
pp. 1309-1312
Author(s):  
Ji Long Su ◽  
Yan Jiao Zhang ◽  
Xing Feng Lian

The Ansys simulate software is utilized to analyze pull-in voltages and stresses of the fixed end of micro- cantilever beam with different thicknesses respectively. Based on the analysis of the electrostatic force at the pull-in voltage, the stress of fixed end of micro-beam and the maximum deflection are obtained. The relationship between the stress of fixed end and thickness is established. The results show that the mutation thickness of the stress and the pull-in voltage are at and respectively , it is consistent with the intrinsic size of the polycrystalline copper micro-beam.


Author(s):  
Xianwei Yuan ◽  
Pengyu Jie ◽  
Yuhao Meng ◽  
Haiping Zhou ◽  
Ke Li ◽  
...  

2001 ◽  
Author(s):  
Giulio Grillo ◽  
Nejat Olgac

Abstract This paper presents an influence region analysis for an actively tuned vibration absorber, the Delayed Resonator (DR). DR is shown to respond to tonal excitations with time varying frequencies [1–3]. The vibration suppression is most effective at the point of attachment of the absorber to the primary structure. In this study we show that proper feedback control on the absorber can yield successful vibration suppression at points away from this point of attachment. The form and the size of such “influence region” strongly depend on the structural properties of the absorber and the primary system. There are a number of questions addressed in this paper: a) Stability of vibration absorption, considering that a single absorber is used to suppress oscillations at different locations. b) Possible common operating frequency intervals in which the suppression can be switched from one point on the structure to the others. A three-degree-of-freedom system is taken for as example case. One single DR absorber is demonstrated to suppress the oscillations at one of the three masses at a given time. Instead of an “influence region” a set of “influence points” is introduced. An analysis method is presented to find the common frequency interval in which the DR absorber operates at all three influence points.


Author(s):  
Ratiba Fatma Ghachi ◽  
Wael Alnahhal ◽  
Osama Abdeljaber

This paper presents a beam structure of a new metamaterial-inspired dynamic vibration attenuation system. The proposed experimental research presents a designed cantilevered zigzag structure that can have natural frequencies orders of magnitude lower than a simple cantilever of the same scale. The proposed vibration attenuation system relies on the masses places on the zigzag structure thus changing the dynamic response of the system. The zigzag plates are integrated into the host structure namely a cantilever beam with openings, forming what is referred to here as a metastructure. Experimental frequency response function results are shown comparing the response of the structure to depending on the natural frequency of the zigzag structures. Results show that the distributed inserts in the system can split the peak response of the structure into two separate peaks rendering the peak frequency a low transmission frequency. These preliminary results provide a view of the potential of research work on active-controlled structures and nonlinear insert-structure interaction for vibration attenuation.


2020 ◽  
Vol 9 (12) ◽  
pp. 25260-25264
Author(s):  
Nanang Endriatno ◽  
Budiman Sudia ◽  
Raden Rinova Sisworo ◽  
Muhammad Faisal

The aim of the study was to analyze the dynamic response along an aluminum cantilever beam. The data measured were displacement (mm), velocity (mm / s), and acceleration (m/s2) with 3 variations of the measurement position on the beam. The 6061 series aluminum beam used have length: 80 cm, height: 32 cm, and width: 32 cm. Data were collected experimentally using a vibration meter to measure beam vibrations at the various positions from the cantilever beam at a distance from support: 10 cm, 35 cm, and 60 cm. The results of the analysis showed that the values ​​of the displacement, velocity and acceleration of the object vibrations change when the measuring point was far from the cantilever support. The maximum displacement value is at 60 cm from the support: 0.02 mm, and the lowest is at 10 cm: 0.12 mm. The velocity value also increases, maximum at 60 cm from the support: 38.58 mm/s and the minimum value at 10 cm: 12.30 mm/s. While the acceleration value, the maximum at 60 cm from the support: 91150 mm/s2 and the minimum at 10 cm: 66900 mm/s2.  


2020 ◽  
Vol 16 (1/2) ◽  
pp. 13
Author(s):  
Jun Wei Sam ◽  
Hock Khuen Cheow ◽  
Jee u Ho ◽  
Hoon Kiat Ng ◽  
Ai Bao Chai

2013 ◽  
Vol 325-326 ◽  
pp. 214-217
Author(s):  
Yong Chen ◽  
Yi Xu

Using nonlinear energy sink absorber (NESA) is a good countermeasure for vibration suppression in wide board frequency region. The nonlinear normal modes (NNMs) are helpful in dynamics analysis for a NESA-attached system. Being a primary structure, a cantilever beam whose modal functions contain hyperbolic functions is surveyed, in case of being attached with NESA and subjected to a harmonic excitation. With the help of Galerkins method and Raushers method, the NNMs are obtained analytically. The comparison of analytical and numerical results indicates a good agreement, which confirms the existence of the nonlinear normal modes.


Author(s):  
J. Hannsen Su

Abstract Conventional vibration isolation mounts are not as effective as expected on a practical foundation whose resonant frequencies normally are within the bandwidth of interest. In addition, the low frequency enhancement is a characteristic of the passive mounts. Applying inertia actuators to the bottom attachment plate of the conventional mounts overcomes these shortcomings and enhances their performance significantly. This design concept has universal application since it is applicable to any dynamic system. It requires very little power and force capacity, i.e., a small percentage of the disturbance force, from the actuators to be effective for frequencies higher than the resonant frequency of the mount itself. The effectiveness of the proposed mounts for the machinery is demonstrated on the load transmissibility reduction at the foundation support (fixed end) due to disturbance from machinery above mounts. On the other hand, the vibration magnitude reduction of equipment above mounts due to disturbance from the foundation is used for evaluating the equipment isolation effectiveness. There is no stabilty or degradation problem when a number of the passive-active mounts are used on the same foundation. Furthermore, the more of this type of mounts used on a foundation the more effective the vibration suppression and the smaller actuator force requirement for each passive-active mount.


2000 ◽  
Author(s):  
Nader Jalili

Abstract A semi-active vibration absorber with adaptive capability is presented to improve wide band vibration suppression characteristics of harmonically excited structures. The absorber subsection consists of a double-ended cantilever beam carrying an intermediate lumped mass. The adaptive capability is achieved through concurrent adjustment of the position of the moving mass, along the beam, to comply with the desired optimal performance. If such an absorber is attached to a vibrating body, it effectively absorbs vibrations at all frequencies that belong to the absorber frequency bandwidth. Numerical simulations are provided to verify the effectiveness of the proposed absorption scheme. It is shown that the tuning strategy tries to follow and match the absorber natural frequency with the excitation frequency. The optimally tuned absorber provides considerable vibration suppression improvement over the passive and de-tuned absorbers, for wide band excitation disturbances.


Sign in / Sign up

Export Citation Format

Share Document