Machining Vibration Suppression of a Cylindrical Part by a Point-Contact Support

2020 ◽  
Author(s):  
Atsushi Matsubara ◽  
Kotaro Mori ◽  
Daisuke Kono
Keyword(s):  
Frequency Response ◽  
Vibration Suppression ◽  
Point Contact ◽  
Aircraft Engine ◽  
Cylindrical Part ◽  
Curved Surface ◽  
Cutting Test ◽  
Support Element ◽  
Simple Support ◽  
Multiple Support

Abstract Aircraft engine cases employ a thin-walled cylindrical structure for the reduction of fuel consumption. The machining of such parts requires support systems as cutting forces generate shell mode vibrations. There has been much research on the design of vibration suppression devices such as mass dampers, tuned mass dampers, active dampers, and fixturing stretch. Although such devices can offer excellent performance in vibration suppression, cost, and time for manufacturing and setup with tuning are problems. In this paper, the test results of a simple support system that suppresses the vibration modes of a cylindrical part are reported. A support element employs two-contacts in the curved surface. Multiple support elements are arranged according to the number of antinodes of shell modes. Each support has two rollers with a rotating head; the roller contact aligned in the curved surface. For the decision of the number of the support elements, modal analysis was carried out for a cylindrical part. An excitation test was carried out to evaluate the frequency response of a supported cylinder, and several peaks in frequency response were found to be suppressed. A cutting test with an endmill was carried out to evaluate the vibration levels. The experimental results show that the support can suppress forced vibration during machining.

Design of a turning cutting tool with large length–diameter ratio based on three-element type vibration absorber

2020 ◽  
Vol 234 (6-7) ◽  
pp. 1032-1043
Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Wenshuo Ma ◽  
Qiang Liu
Keyword(s):  
Frequency Response ◽  
Cutting Tool ◽  
Vibration Suppression ◽  
Diameter Ratio ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Target Mode ◽  
Large Length ◽  
Element Type ◽  
Structural Parts

The vibration absorber has been effective in vibration control. From the demand of manufacturing structural parts with a deep hole, the design of a turning cutting tool with large length–diameter ratio is presented. An analytical approach of acquiring frequency response of primary structure equipped with typical single-degree-of-freedom vibration absorbers is formulated, and background modes are incorporated with the purpose of achieving an accurate tuning of vibration absorber. Specifically, the three-element type is investigated as the damping element of the vibration absorber embedded in the cutting tool contributes to the stiffness, although it demonstrates medium performance of vibration suppression according to non-dimensional analysis. The experimentally tuned frequency response function of the turning cutting tool with three-element vibration absorber achieves 87.1% reduction on the amplitude of the target mode. Finally, several configurations of internal turning operations are carried out to validate the design of the vibration absorber.

THE COMPARISON OF SLAB DEFLECTION BASED ON FIELD MEASUREMENT, MANUAL CALCULATION (LEVY METHOD) AND FINITE ELEMENT METHOD (PROGRAM SAP 2000)

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Irpan Hidayat ◽  
Made Suangga ◽  
Fransiscus Leonardo ◽  
Godeliva Juliastuti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Field Measurement ◽  
Concrete Slab ◽  
Field Measurements ◽  
Large Numbers ◽  
Support Element ◽  
Simple Support ◽  
Manual Calculation ◽  
Element Method

Concrete slab is a structural system that uses beams as a support element slab. The placement of beams at the whole edges of slab, so that the load received by the slab can be transfer into beams. The slab will be deformed/deflection when the loads are given. The value of slab deflection is dependent on the placement of beam support at the edges. This research was conducted on the two boundary condition that is simple support at the two edges and rigid support at whole edges. Calculating the value of deflection based on the results of field measurements and then compared with Marcus Levy method and Finite element method (FEM). Based on the study, the numbers of mesh affected to the value of deflection. The results of deflection with Program SAP 2000 will be approached deflection by Method M. Levy for the mesh division with large numbers. The deflection of slab on the field measurement approached manual calculations and Program SAP2000 with a simple support at the surrounding the edges.  The comparison of deflection was obtained for the simple support based on manual calculations and field measurement has a difference of 0.3% - 1%. Where the value of deflection on the field measurement is smaller than the manual calculation.

Vibration Suppression Using a Proofmass Actuator Operating in Stroke/Force Saturation

1991 ◽  
Vol 113 (4) ◽  
pp. 423-433 ◽  
Author(s):  
D. K. Lindner ◽  
T. P. Celano ◽  
E. N. Ide
Keyword(s):  
Frequency Response ◽  
Vibration Suppression ◽  
Simple Procedure ◽  
Flexible Structures ◽  
Weight Ratio ◽  
Saturation Curve ◽  
Loop Structure ◽  
Stroke Length ◽  
Single Input Single Output ◽  
Single Output

We consider proofmass actuators for vibration suppression in flexible structures. Proofmass actuators appear to have a significant force-to-weight ratio over other types of actuators; hence, there has been considerable interest in them recently. These actuators, however, have a maximum force capability imposed in part by the stroke length of the proofmass. This nonlinearity is difficult to handle because this constraint cannot be violated (unlike saturation of electronic devices). Furthermore, this constraint is peculiar to this type of actuator. In this paper we consider the control loop structure of a feedback control system which contains a proofmass actuator for vibration suppression. This loop structure is decomposed into inner control loops directly related to the actuator and outer loops which add damping to the structure. The inner loops determine the frequency response of the actuator. Evidently, when the frequency response of the actuator is matched to the stroke/force saturation curve, the actuator is most effective in the vibration suppression loops. Since the stroke/force saturation curve is characterized by the stroke length, mass of the proofmass, and the maximum current delivered by motor electronics, this actuator can be easily sized for a particular application. We also discuss the interaction between the inner loops around the actuator and the structure (with the vibration loops open). To illustrate our results, we consider linear DC motors as proofmass actuators for the COFS-I Mast. To discuss the interaction the actuator and the structure, we develop a simple result based on classical control theory. This result is of independent interest since it leads to a simple procedure for designing low order compensators for single-input-single-output systems with poles near the imaginary axis.

scholarly journals Multilayer Strip Dipole Antenna Using Stacking Technique and Its Application for Curved Surface

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Charinsak Saetiaw ◽  
Chanchai Thongsopa
Keyword(s):  
Resonance Frequency ◽  
Frequency Response ◽  
Dipole Antenna ◽  
Curved Surface ◽  
Uhf Rfid ◽  
Laminate Layer ◽  
Rfid Applications

This paper presents the design of multilayer strip dipole antenna by stacking a flexible copper-clad laminate utilized for curved surface on the cylindrical objects. The designed antenna will reduce the effects of curving based on relative lengths that are changed in each stacking flexible copper-clad laminate layer. Curving is different from each layer of the antenna, so the resonance frequency that resulted from an extended antenna provides better frequency response stability compared to modern antenna when it is curved or attached to cylindrical objects. The frequency of multilayer antenna is designed at 920 MHz for UHF RFID applications.

Active vibration control experiments on an AgustaWestland W30 helicopter airframe

2011 ◽  
Vol 226 (6) ◽  
pp. 1504-1516 ◽  
Author(s):  
J E Mottershead ◽  
M Ghandchi Tehrani ◽  
S James ◽  
P Court
Keyword(s):  
Vibration Control ◽  
Frequency Response ◽  
Closed Loop ◽  
Vibration Suppression ◽  
Active Vibration Control ◽  
Input Voltage ◽  
Open Loop ◽  
Control Technique ◽  
Response Functions ◽  
Frequency Response Functions

This article describes the practical application of a vibration control technique, developed by the authors and known as the receptance method, to the AgustaWestland W30 helicopter airframe in the vibration test house at Yeovil. The experimental work was carried out over a total of 5 days in two visits to the Yeovil site during February and March 2011. In the experiments, existing electro-hydraulic actuators were used; they were built into the airframe structure and originally designed for vibration suppression by the methodology known as active control of structural response developed at the AgustaWestland Helicopters site in Yeovil. Accelerometers were placed at a large number of points around the airframe and an initial open-loop modal test was carried out. In a subsequent test, at higher actuator input voltage, considerable non-linearity was discovered, to the extent that the ordering of certain modes had changed. The vibration modes were, in general, heavily damped. Control was implemented using measured frequency response functions obtained at the higher input level. After acquiring the necessary measurements, simulations were carried out and the controller was implemented using MATLAB/Simulink and dSPACE. The closed-loop poles were mostly assigned with small real parts so that the system would be lightly damped and sharp peaks would be clearly apparent in the measured closed-loop frequency response functions. Locations of the open- and closed-loop poles in the complex s-plane were obtained to verify that the required assignment of poles had taken place.

H 2, Mixed H2/H∞ and H2/L1 Optimally Tuned Passive Isolators and Absorbers

1998 ◽  
Vol 120 (2) ◽  
pp. 282-287 ◽  
Author(s):  
Wassim M. Haddad ◽  
Ali Razavi
Keyword(s):  
Frequency Response ◽  
Ad Hoc ◽  
Vibration Suppression ◽  
Peak Frequency ◽  
Optimization Method ◽  
Worst Case ◽  
Practical Applications ◽  
System Vibration ◽  
Response Performance ◽  
Optimization Schemes

In many practical applications, unbalanced rotating machinery cause vibrations that transmit large oscillatory forces to the system foundation. Using ad hoc optimization schemes tuned isolators and absorbers have traditionally been designed to suppress system vibration levels by attempting to minimize the peak frequency response of the force/displacement transmissibility system transfer function. In this paper, we formulate the classical isolator and absorber vibration suppression problems in terms of modern system theoretic criteria involving H2 (shock response), mixed H2/H∞ (worst-case peak frequency response), and mixed H2/L1 (worst-case peak amplitude response) performance measures. In particular, using a quasi-Newton optimization method we design H2, mixed H2/H∞ and mixed H2/L1 optimally tuned isolators and absorbers for multi-degree-of-freedom vibrational systems. Finally, we compare our results to the classical Snowdon and Den Hartog absorbers.

Investigations of a piezoelectric metastructure using negative-resistance circuits to enhance the bandgap performance

2021 ◽  
pp. 107754632110105
Author(s):  
Yisheng Zheng ◽  
Junxian Zhang ◽  
Yegao Qu ◽  
Guang Meng
Keyword(s):  
Frequency Response ◽  
Physical Model ◽  
Electrical Resistance ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Wave Dispersion ◽  
Negative Resistance ◽  
Experimental Setup ◽  
Response Functions ◽  
Local Resonance

The local-resonance bandgap performance of piezoelectric metastructures could be deteriorated by the inherent resistance existing in the piezoelectric patches and the inductors of shunting circuits. In this article, we propose to use negative-resistance circuits to cancel the inherent electrical resistance and therefore enhance vibration reduction performance in the bandgap. The physical model of the piezoelectric metastructure with negative-resistance shunting circuits is firstly illustrated, followed by analyzing its wave dispersion relations and frequency response functions. The enhanced bandgap performance of the piezoelectric metastructure facilitated by negative-resistance circuits is verified with the analytical results. Last, an experimental setup of the piezoelectric metastructure is built. The experimental results demonstrate that the vibration suppression performance in the bandgap is significantly increased by using negative-resistance circuits, and a higher value of negative resistance could lead to larger vibration reduction. Overall, the results of this article provide a novel means to enhance the local-resonance bandgap performance of piezoelectric metastructures.

Evaluation of Relationship Between Shape of a Rigid Body Unifilar Centrifugal Pendulum Vibration Absorber and Vibration Suppression Performance

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Ryota Okumura ◽  
Shota Yabui ◽  
Xiangyu Jiang
Keyword(s):  
Rigid Body ◽  
Frequency Response ◽  
Torsional Vibration ◽  
Vibration Suppression ◽  
Radius Of Gyration ◽  
Vibration Absorbers ◽  
Shape Parameters ◽  
Centrifugal Pendulum Vibration Absorber ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
Good Agreement

Abstract The torsional vibration hinders the reduction of automobile exhaust gas emitted by using engines with a reduced number of cylinders. Centrifugal pendulum vibration absorbers (CPVA) have been used in engines to suppress torsional vibration. To clarify the dynamics of CPVAs, much analysis has been conducted using the point mass CPVA as the model of rigid body bifilar CPVA. However, few attempts have been made to analyze the rigid body unifilar CPVA on vibration suppression performance in frequency response. In this study, the authors have analyzed the dynamics of the rigid body unifilar CPVA, focusing on the influence of shape parameters. The results verified that the shape parameters, which relating to moment of inertia or radius of gyration of rigid body unifilar CPVA, influence the vibration suppression performance in frequency response. Moreover, the numerical simulation results were confirmed experimentally and showed in good agreement with the experimental results, and both indicated the dependence of the vibration suppression performance on the shape parameters of the rigid body unifilar CPVA.

scholarly journals Dynamic characterizations of underwater structures using noncontact vibration tests based on nanosecond laser ablation in water: evaluation of passive vibration suppression with damping materials

2017 ◽  
Vol 24 (16) ◽  
pp. 3714-3725 ◽  
Author(s):  
Naoki Hosoya ◽  
Itsuro Kajiwara ◽  
Koh Umenai ◽  
Shingo Maeda
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Vibration Suppression ◽  
Pass Filter ◽  
Reliability Factor ◽  
Measured Frequency ◽  
Measured Frequency Response ◽  
Underwater Structure ◽  
Underwater Structures

Recently, the demand for higher performing underwater structures under diverse conditions has increased. Examples include improved precision and speed of the position control of robot manipulators. To prevent the control spillover problems when active controls are used, a control system is typically constituted with a low-pass filter to eliminate all modes except for the target modes. However, experimentally measuring the dynamic properties of an underwater structure in an environment where the structure and a fluid continuously influence each other is difficult. We have recently proposed a noncontact vibration testing method for dynamic characterizations of underwater structures in which the response to a laser ablation excitation force is measured by laser Doppler vibrometer. Integrating passive control using a vibration-damping material affixed onto the underwater structure and active control constituted with the low-pass filter may realize a more cost-effective system. To develop this combined control into a practical method, the reliability of the measured frequency response function must be validated. Additionally, the applicable frequency range must be expanded to encompass the high-frequency region (several tens of kHz) so that the vibration suppression quality of underwater structures can be evaluated. Herein we quantify the effect of random measurement errors on the measured frequency response function with a reliability factor based on the concept of coherence functions. Using the measured frequency response function with a reliability factor, we demonstrated that our method can evaluate passive vibration suppression effect of an underwater structure with a damping material in high-frequency ranges up to 20 kHz.

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