scholarly journals Static and Dynamic Analysis of a 6300 KN Cold Orbital Forging Machine

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 7
Author(s):  
Zhiqiang Gu ◽  
Mingzhang Chen ◽  
Chaoyang Wang ◽  
Wuhao Zhuang
Keyword(s):  
Fatigue Life ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Optimization Method ◽  
Vertical Vibration ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Low Frequency Vibration ◽  
Orbital Forging

In cold orbital forging (COF) processes, large stress, displacement and vertical vibration of the COF machine are bad for the quality of the part and the fatigue life of the COF machine. It is necessary to investigate the static and dynamic performance of the COF machine and provide methods for reducing the stress, displacement and vertical vibration of the COF machine. In this paper, finite element analysis, theoretical analysis, numerical simulation and experimental analysis were applied to study the static and dynamic performance of a 6300 KN COF machine. The static and dynamic analyses were verified effectively by carrying out strain and vertical vibration test experiments. In the static analysis, the large stress and displacement positions of the COF machine were mainly distributed near the working table and the junction between the working table and the column. Large stress and displacement will be bad for the quality of the part and the fatigue life of the COF machine. Structural optimizations of the COF machine include ribbed plates on the working table and beam. This structural optimization method of the COF machine obviously reduced the stress and displacement of the COF machine. When the angular velocities of the eccentric rings were 8π rad/s, the vertical vibration of the swing shaft is a low-frequency vibration. The existence of absorber obviously reduced the vertical vibration of the COF machine.

System Identification for Boring Bar Chatter Control

1993 ◽  
Author(s):  
Jonathan A. Embry ◽  
Suzanne Weaver Smith ◽  
Bruce L. Walcott
Keyword(s):  
Aerospace Industry ◽  
Low Frequency ◽  
Structure Identification ◽  
Space Structures ◽  
Modal Interactions ◽  
Element Analysis ◽  
Flexible Space Structures ◽  
Boring Bar ◽  
Low Frequency Vibration ◽  
Chatter Control

Abstract The boring bar is used to provide smooth, accurate cuts in materials. However, when the length to diameter (L/D) ratio of the boring bar becomes large, low-frequency vibration, or chatter, results. Initial attempts to control this unwanted vibration with an active absorber have been successful, but in some configurations problems remain. In this paper, algorithms for flexible structure identification widely used in the aerospace industry are applied to a number of boring bar setups to identify the vibration characteristics of each system. Emphasis is placed on one class of methods which includes the Eigensystem Realization Algorithm (ERA), developed for identification of flexible space structures. The resulting identified characteristics are compared and contrasted. Results are also compared to finite element analysis predictions. From the current identification results, implications for chatter control are discussed, including the possibility of nonlinear modal interactions.

scholarly journals Dynamic performance analysis and parameters perturbation study of inerter–spring–damper suspension for heavy vehicle

2020 ◽  
pp. 146134842096289
Author(s):  
Xiaofeng Yang ◽  
Long Yan ◽  
Yujie Shen ◽  
Hongchang Li ◽  
Yanling Liu
Keyword(s):  
Ride Comfort ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Angular Acceleration ◽  
Vertical Vibration ◽  
Heavy Vehicle ◽  
The Road ◽  
Multi Objective Genetic Algorithm ◽  
Parameters Perturbation ◽  
Dynamic Performance Analysis

Inerter, a new type of mass element, can increase the inertia of motion between two endpoints. In order to study the dynamic inertia effect of inerter–spring–damper suspension for heavy vehicle on ride comfort and road friendliness, the inerter–spring–damper suspension is applied and its mechanism is studied. This paper establishes a half vehicle model of inerter–spring–damper suspension for heavy vehicle. The parameters of inerter–spring–damper suspension for heavy vehicle are optimized by multi-objective genetic algorithm and system simulations are carried out. The parametric influence of different spring stiffness, damping coefficient, inertance, and load on suspension performance is also studied. The simulation results demonstrate that the centroid acceleration and pitch angular acceleration are improved by 24.90% and 23.54%, respectively, and the comprehensive road damage coefficient is reduced by 4.05%. The results illustrate that the inerter–spring–damper suspension can decrease the vertical vibration of vehicle suspension especially in low frequency and reduce the road damage. The analyses of suspension parameters perturbation reveal their different effect laws of the different wheels on vehicle ride comfort and road friendliness, which provide a theoretical basis for setting parameters of inerter–spring–damper suspension.

Influence of Structure Parameters on the Permanent Magnetic Planetary Gear Forced Vibration Frequency Response

2014 ◽  
Vol 635-637 ◽  
pp. 168-171
Author(s):  
Xue Jun Zhu ◽  
Li Zhong Xu
Keyword(s):  
Dynamic Performance ◽  
Low Frequency ◽  
Planetary Gear ◽  
System Structure ◽  
Structure Parameters ◽  
Magnetic Parameters ◽  
Low Frequency Vibration ◽  
Magnetization Intensity ◽  
Pair Number ◽  
Forced Responses

The time and frequency forced responses for the permanent magnetic planetary gear drive were computed and analyzed. The influence of magnetization intensity and pole pair number to frequency forced responses is discussed. Results show that the dynamic displacement when only considering output excitation is larger than that when only considering input excitation,and magnetic parameters have obvious effects on the low frequency vibration amplitude of elements. When magnetization intensity and pole pair number are too large or too small, they will seriously affect the dynamic performance of the system. So, selecting rational system structure parameters is very important, which can avoid system elements generating larger vibration.

In Situ Measurement of Ground Vibration Induced by Inter-City Express Train

2012 ◽  
Vol 204-208 ◽  
pp. 502-507 ◽  
Author(s):  
Quan Min Liu ◽  
Xun Zhang ◽  
Zhi Jun Zhang ◽  
Xiao Zhen Li
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Ground Vibration ◽  
Vertical Vibration ◽  
Test Results ◽  
Low Frequency Vibration ◽  
Express Train ◽  
Environmental Vibration ◽  
Logarithmic Relationship

On the basis of the measured ground borne vibration of some inter-city express railway viaduct, test results analysis shows that: the test environmental vibration is under the limit set by standard of environmental vibration in urban area; whether transverse or vertical vibration, a rapid attenuation of the peak acceleration with the distance to the up-track center is observed, however the vibration at 7.5m appears to be amplified; the ground vibration with the distance conforms to a logarithmic relationship; the horizontal ground vibration at 7.5m caused by the elevated rail transit is larger 3.6cm/s2 than the vertical vibration; low-frequency vibration transfers farther than high frequency vibration; the eccentric effect of two-track viaduct is obvious.

Application of Topological Optimization on Aluminum Alloy Automobile Wheel Designing

2012 ◽  
Vol 562-564 ◽  
pp. 705-708
Author(s):  
Zhi Jun Zhang ◽  
Hong Lei Jia ◽  
Ji Yu Sun ◽  
Ming Ming Wang
Keyword(s):  
Topology Optimization ◽  
Lightweight Design ◽  
Optimization Method ◽  
Variable Density ◽  
Topological Optimization ◽  
Optimal Topology ◽  
Element Analysis ◽  
Material Interpolation ◽  
Strength And Stiffness

Topology optimization method based on variable density and the minimum compliance objective function was used on designing the wheel spokes. SIMP material interpolation model was established to compensate these deficiencies of variable density method. Considering manufacturing process and stress distribution, five bolt wheels was chose to topology optimization. The percentage of material removal of the optimal topology 40% was reasonable. Finite element analysis was used to test the strength and stiffness of the structure of the wheel, the result meets the requirements after wheel topology optimization, and reduces the quality of wheels to 7.76kg, achieve the goals of lightweight design.

scholarly journals Performance Enhancement of a Multiresonant Piezoelectric Energy Harvester for Low Frequency Vibrations

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2770 ◽  
Author(s):  
Iman Izadgoshasb ◽  
Yee Lim ◽  
Ricardo Vasquez Padilla ◽  
Mohammadreza Sedighi ◽  
Jeremy Novak
Keyword(s):  
Cantilever Beam ◽  
Performance Enhancement ◽  
Low Frequency ◽  
Design Parameters ◽  
Vibration Source ◽  
Element Analysis ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Low Frequency Vibration ◽  
External Power Source

Harvesting electricity from low frequency vibration sources such as human motions using piezoelectric energy harvesters (PEH) is attracting the attention of many researchers in recent years. The energy harvested can potentially power portable electronic devices as well as some medical devices without the need of an external power source. For this purpose, the piezoelectric patch is often mechanically attached to a cantilever beam, such that the resonance frequency is predominantly governed by the cantilever beam. To increase the power generated from vibration sources with varying frequency, a multiresonant PEH (MRPEH) is often used. In this study, an attempt is made to enhance the performance of MRPEH with the use of a cantilever beam of optimised shape, i.e., a cantilever beam with two triangular branches. The performance is further enhanced through optimising the design of the proposed MRPEH to suit the frequency range of the targeted vibration source. A series of parametric studies were first carried out using finite-element analysis to provide in-depth understanding of the effect of each design parameters on the power output at a low frequency vibration. Selected outcomes were then experimentally verified. An optimised design was finally proposed. The results demonstrate that, with the use of a properly designed MRPEH, broadband energy harvesting is achievable and the efficiency of the PEH system can be significantly increased.

Improvement of Low Frequency Vibration Isolation Capability of AMB Using a Cascade PID Controller

2018 ◽  
Author(s):  
Yixin Su ◽  
Yanhui Ma ◽  
Yongpeng Gu ◽  
Suyuan Yu ◽  
Gexue Ren
Keyword(s):  
Pid Controller ◽  
Vibration Isolation ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Control Parameters ◽  
Control Loops ◽  
Low Frequency Vibration ◽  
Wide Range

In contrast with traditional mechanical bearing, Active magnetic bearing (AMB) has no friction and lubrication, and its dynamic performance can be adjusted by active control. To isolate low frequency vibration of the rotating machinery under 50Hz, a novel design of cascade PID controller (CPC) with two control loops for AMB is proposed. The main loop is a position loop and the secondary loop is a transmission force loop. According to the theoretical derivations in this study, the CPC controls both the rotor position and the transmission force. Even when the control parameters maintain constant, the dynamic characteristic parameters, equivalent stiffness and equivalent damping, vary with frequency continuously and smoothly. Therefore, they can be adjusted in a wide range to achieve isolation of low frequency vibration when using proper control parameters. A simulation example shows that the transmission force with a CPC is lower in the 8–50Hz when the rotor displacement is almost same as with a single stage PID controller (SSPC). Experimental verification was carried out in an experimental bench of AMB under unbalanced rotor condition. Results show that a CPC can reduce the vibration acceleration at 15–50Hz especially near the peaks. Simulation and experimental results well demonstrate the effectiveness and guaranteed stability of the CPC in the present study.

Static Analysis of a Laminated Rubber-Metal Spring Using Finite Element Method

2013 ◽  
Vol 845 ◽  
pp. 86-90 ◽  
Author(s):  
Azma Putra ◽  
Siti Norfarizan ◽  
Haryanti Samekto ◽  
Mohd Azli Salim
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Strain Distribution ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Vertical Vibration ◽  
Stress Distributions ◽  
Element Analysis ◽  
High Frequency Excitation ◽  
Earthquake Vibration

The laminated rubber-metal spring has been widely applied for earthquake vibration isolation which deals mainly for horizontal motion at a very low frequency input. This article presents the effect of a vertical vibration input, which is also aimed at applying the laminated spring for high frequency excitation. Static analysis is discussed here using the Finite Element Analysis (FEA) to observe the stress and strain distribution as well as the safety factor of the isolator due to the axial force. Solid rubber spring experiences greater deformation while it reduces for the laminated rubber-metal spring as more plates are embedded in the rubber. However, higher stress distributions occur on spring with multiple plates compared to solid rubber and the stress concentrate on steel plate layers. Strain distribution was observed to be high at solid rubber spring and it is decreasing on the laminated rubber-metal spring. The critical part for the strain distribution in the laminated rubber-metal spring is in the rubber layers.

scholarly journals Low-Frequency Vibration Testing of Huge Bucket Wheel Excavator Based on Step-Decay Signals

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Y. Z. Jiang ◽  
C. J. Liu ◽  
X. J. Li ◽  
K. F. He ◽  
D. M. Xiao
Keyword(s):  
Fatigue Life ◽  
Natural Frequencies ◽  
Low Frequency ◽  
Vibration Testing ◽  
Testing Methods ◽  
Testing Method ◽  
Low Frequency Vibration ◽  
Free Decay ◽  
Supporting Rollers ◽  
Excitation Method

The low-frequency vibration of the bucket wheel excavator has an important impact on the fatigue life of the structures. For conventional vibration testing methods, it is difficult and expensive to excite the overall low-frequency vibration of the whole machine. Hence, in this paper, the excitation method that uses the belt-supporting rollers on the boom as an exciter is tried to excite the low-frequency vibration, so that the low natural frequencies can be identified by Fourier transforming the free decay signals caused by the sudden power off. By this method, the first five natural frequencies are obtained, and the results are verified through corresponding computational numerical model of the bucket wheel excavator. It can be concluded that the proposed testing method can achieve the same accuracy but is much more convenient and costs less than existing methods.

scholarly journals Influence of Mooring Tension on Dynamic Performance of Semi-submersible Wind Turbine under Typhoon Condition

2021 ◽  
Vol 2087 (1) ◽  
pp. 012030
Author(s):  
Liwei Zhang ◽  
Zhi Sun ◽  
Boyuan Qiu ◽  
Yilie Hou ◽  
Xin Li
Keyword(s):  
Wind Turbine ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Internal Force ◽  
Dynamic Responses ◽  
Wave Frequency ◽  
Wave Load ◽  
Element Analysis ◽  
Internal Forces ◽  
Cfd Method

Abstract A numerical model of a 5 MW semi-submersible wind turbine is established based on the reference wind turbine of American national renewable energy laboratory (NREL). The nominal diameter of the mooring chains was determined after the static wind load and wave load of the turbine under the action of typhoon being calculated by CFD method and Morison method. Finally, the dynamic responses of the turbine and the internal forces of the chains are obtained by the dynamic finite element analysis for three cases. The results show that when pretension chains are used, the turbine motion frequency is consistent with wave frequency, the surge is small, the pitch is reciprocally symmetrical, and the peak internal force of the chains is quite high. When mooring chains without pretension are adopted, the motion of the turbine consists of low-frequency drift and forced motion in sync with the wave frequency, the pitch is asymmetrical, and the internal tension force of the chains is relatively low.

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