scholarly journals Inertial Vibration Characteristics of Track Chassis Caused by Reciprocating Motion of Crank Slider

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Zhong Tang ◽  
Yu Li ◽  
Yuepeng Zhou ◽  
Haotian Zhang
Keyword(s):  
Excitation Frequency ◽  
Vertical Vibration ◽  
Vibration Characteristics ◽  
The Self ◽  
Force Balance ◽  
Inertia Force ◽  
Natural Mode ◽  
Reciprocating Motion ◽  
Measuring Point ◽  
Track Beam

The crank slider of self-propelled baling machinery is used for straw compression on the crawler chassis structure. During the reciprocating motion of the crank slider, the inertia of the piston will cause a greater shock to baling machinery. In this paper, the inertia of the crank slider piston was analyzed on crawler chassis. The model and parameter values of the inertia force balance of the crank slider were established by the complete balance method. The test mode was used to analyze the natural mode and mode shape of the piston. The vertical vibration amplitudes of the crawler chassis beam were tested and used to reflect the specific inertial vibration characteristics of the self-propelled baling machinery caused by the reciprocating motion of the piston. The inertial vibration caused by the reciprocating motion of the crank slider was eliminated by the method of weighting the tail of the track beam. Results indicated that the self-balancing counterweight of the crank slider was 261.82 kg. The six natural modal frequencies of the piston were 4.62, 17.26, 29.82, 63.85, 83.73, and 141.58 Hz, respectively. During the reciprocating motion of the piston, the first-order frequency of the piston would be excited by feeding auger excitation frequency of 3.77 Hz and may cause resonance. And, the vertical vibrates of track beam was based on the measuring point 6 as a fulcrum. Adding a counterweight of 265 kg at the end of the track chassis would completely eliminate the self-propelled baling machinery inertial vibration caused by the reciprocating motion of the crank slider.

scholarly journals Vibration Analysis and Parameter Optimization of the Longitudinal Axial Flow Threshing Cylinder

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 571
Author(s):  
Jinwu Wang ◽  
Changsu Xu ◽  
Yanan Xu ◽  
Xin Qi ◽  
Ziming Liu ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Lightweight Design ◽  
Excitation Frequency ◽  
Axial Flow ◽  
Rotation Frequency ◽  
Vibration Characteristics ◽  
Inertia Force ◽  
Rotational Inertia ◽  
Maximum Deformation ◽  
Frequency Maximum

The longitudinal axial flow threshing cylinder of the full feeding rice combine harvester is widely used in China and works with violent vibration. To explore the source of the excitation affecting the vibration and to reduce the vibration, a finite element modal analysis and multipoint input and multipoint output (MIMO) modal test were performed to solve the natural vibration characteristics. By analyzing the excitation frequency, we concluded that the main reason for the resonance was the coupling between the rotation frequency of the threshing cylinder and the first natural frequency. To avoid the influence of resonance and realize a lightweight design, we proposed a combination of size optimization and topology optimization. The second rotation orthogonal combination test was designed to analyze the first natural frequency, maximum stress, and maximum deformation of the threshing cylinder, and the threshing cylinder was reconstructed as a central symmetrical structure to balance the rotational inertia force. The field experiment results showed that the amplitudes of the optimized threshing cylinder were significantly lower than those of the original threshing cylinder. This study provides ideas for solving the vibration characteristics of rotating parts and provides an important reference for the design of vibration reduction and weight reduction of key parts in the field of agricultural machinery.

Self-Vibration Characteristics of Plane Gate in Inverted Siphon Project

2012 ◽  
Vol 160 ◽  
pp. 64-68
Author(s):  
Hui Fang Xue ◽  
You Wang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Element Model ◽  
Vibration Characteristics ◽  
The Self ◽  
Vibration Modes ◽  
Vibration Frequencies ◽  
Small Opening ◽  
First Order ◽  
Inverted Siphon

Based on the vibration problem of the plane gate in the inverted siphon exit of a large-scale hydraulic project in northern Xinjiang, the software ANSYS is used to build the entity model and finite element model. Considering the influence of fluid-solid coupling, the self-vibration characteristics of the gate in the water and without water are analyzed. The first six self-vibration frequencies and vibration modes of the gate are calculated. The results show that the height of water has a significant impact on the self-vibration frequencies of the plane gate. The first order natural frequency on the condition of small opening is decreased by 28.5%. It shows that the structure of the plane gate must be improved.

Experimental study on vertical vibration characteristics of medium-low speed maglev vehicle when standing still on steel beams

2021 ◽  
pp. 095440972110324
Author(s):  
Miao Li ◽  
Xiaohao Chen ◽  
Shihui Luo ◽  
Weihua Ma ◽  
Cheng Lei ◽  
...  
Keyword(s):  
Coupled System ◽  
Vertical Vibration ◽  
Vibration Characteristics ◽  
Steel Beams ◽  
Steel Beam ◽  
Air Spring ◽  
Low Speed ◽  
Maglev Vehicle ◽  
Excited Vibration ◽  
Eigen Frequencies

Levitation stability is the very basis for the dynamic operation of Electromagnetic Suspension (EMS) medium-low speed maglev trains (MSMT). However, self-excited vibration tends to occur when the vehicle is standing still above the lightweight lines, which remains a major constraint to the promotion of medium-low speed maglev technology. In order to study the vertical vibration characteristics of the coupled system of MSMT when it is standing still above lightweight lines, levitation tests were carried out on two types of steel beams: steel beam and active girder of the turnout, with a newly developed maglev vehicle using levitation frames with mid-set air spring. Firstly, modal tests were carried out on the steel beam to determine its natural vibration characteristics; secondly, the acceleration signals and the dynamic displacement signals of the air spring obtained at each measurement point were analyzed in detail in both the time and frequency domains, and the vertical ride comfort was assessed by means of the calculated Sperling index. Subsequently, theoretical explanations were given for the occurrence of self-excited vibration of coupled system from the perspective of the vehicle-to-guideway vibration energy input. Results show that the eigen frequencies of the vehicle on the steel beam and the turnout are 9.65 Hz and 2.15 Hz, respectively, the former being close to the natural frequency of the steel beam while the latter being close to the natural frequency of the air spring suspension system, thus causing the self-excited vibration of the coupled system. It is recommended to either avoid the main eigen frequencies of the coupled system or to increase the damping of the corresponding vibration modes to guarantee a reliable coupled system for its long-term performance. These results may provide valuable references for the optimal design of medium-low speed maglev systems.

A Study on the Instability of Disk-Shaped Gear

1999 ◽  
Author(s):  
Guangming Ren ◽  
Litang Yan
Keyword(s):  
Perturbation Method ◽  
Traveling Wave ◽  
Vibration Characteristics ◽  
Exciting Force ◽  
Nonlinear Perturbation ◽  
The Self ◽  
Experimental Investigations ◽  
Damping Force ◽  
Bevel Gears ◽  
Theory And Experiment

Abstract In this paper the theory and experiment concerning vibration instability of disk-shaped gear are presented. At first the self-exciting force of gear is searched and the works done by the exciting force and damping force are analyzed. Then the vibration instability of the disk-shaped plain gear is studied with multiple scale’s method of the nonlinear perturbation method. The vibration characteristics of a coupled pair of bevel gears are investigated experimentally. Both theoretical and experimental investigations show that there are actually self-exciting vibrations on the gear. Under certain conditions the forward traveling wave vibration of the driving gear and the backward traveling wave vibration of the driven gear can be instable.

Dynamic Experimental Investigation on the Self-Vibration Characteristics of Liquid Storage Tanks Under Seismic Excitations

2013 ◽  
Author(s):  
Zhou Fang ◽  
Zhiping Chen ◽  
Guodong Jia ◽  
Hui Wang ◽  
Xiang Li
Keyword(s):  
Large Scale ◽  
Vibration Characteristics ◽  
The Self ◽  
Earthquake Simulation ◽  
Seismic Excitations ◽  
Storage Model ◽  
Design Standard ◽  
Finite Element Software ◽  
Liquid Storage ◽  
Cylindrical Steel

A large-scale earthquake simulation experiment about the unanchored cylindrical steel liquid storage model tanks has been completed. The self-vibration characteristics of the model tanks with liquid inside were investigated based on the experimental data of the acceleration dynamic response. The seismic table test, the analysis methods are designed and conducted, and experimental results of the model tanks were carefully measured. Furthermore, ANSYS finite element software was used to simulate and calculate the low order natural frequency and fundamental frequency of the model tank systems according to the national design standard. The reasons for the existence of consistency and differences among the results obtained from experiments, numerical simulation and national design standard were discussed.

Experimental Research on Dynamic Characteristics of a Rolling Agricultural Tire (Influence of Running Condition)

2013 ◽  
Author(s):  
Katsuhide Fujita ◽  
Takashi Saito ◽  
Mitsugu Kaneko
Keyword(s):  
Natural Frequency ◽  
Dynamic Behavior ◽  
Experimental Research ◽  
Dynamic Characteristics ◽  
Excitation Frequency ◽  
Road Surface ◽  
Natural Mode ◽  
The Road ◽  
On The Road ◽  
Agricultural Machines

When agricultural machines are operated on pavements, the vibration and noise caused by the interaction between the tire lugs and the road surface are inevitable. In conventional studies, it is considered that the dynamic behavior of a rolling agricultural tire is influenced by the vibration characteristics of the tire. Resonance occurs when the lug excitation frequency of the tire, which is defined as the lug number multiplied by the number of revolutions of the tire, becomes equal to the natural frequency of the tire. In other words, the rolling tire shows large vibrations in the direction of the natural mode corresponding to the natural frequency of the tire. However, in the conventional equipment, the diameter of the drum is smaller than that of the tire. Therefore, the real running condition on the road was not realized by the rolling test using the conventional equipment. In this study, a new equipment is produced to realize the running condition in the rolling test. The dynamic and vibratory characteristics of operating agricultural machine are investigated by using this new equipment. The obtained results are compared to the conventional ones and the influence of the running condition on dynamic characteristics of rolling tire is investigated.

Experimental Study on Dynamic Behavior of a Rolling Agricultural Tire

2012 ◽  
Author(s):  
Katsuhide Fujita ◽  
Takashi Saito ◽  
Toru Yamazaki
Keyword(s):  
Natural Frequency ◽  
Dynamic Behavior ◽  
Sound Pressure ◽  
Vibration Mode ◽  
Excitation Frequency ◽  
Resonance State ◽  
Natural Mode ◽  
Pressure Measurements ◽  
The Road ◽  
Agricultural Machines

When agricultural machines are operated on pavements, the vibration and noise caused by the interaction between the tire lugs and the road surface are inevitable. In conventional studies, it is considered that the dynamic behavior of a rolling agricultural tire is influenced by the vibration characteristics of the tire. Resonance occurs when the lug excitation frequency of the tire, which is defined as the lug number multiplied by the number of revolutions of the tire, becomes equal to the natural frequency of the tire. In other words, the rolling tire shows large vibrations in the direction of the natural mode corresponding to the natural frequency of the tire. However, the vibration mode of the rolling tire in resonance state has not yet been clarified. In this study, it is confirmed that the dynamic behavior of the rolling tire can be evaluated by performing sound pressure measurements using closely located microphones to the tire. Further, the vibration mode in the resonance state is identified by performing simultaneous measurements of the sound pressure, and the vibration mode corresponds to the natural mode of the tire is confirmed as well.

Forced Response of a Squeeze Film Damper and Identification of Force Coefficients From Large Orbital Motions

2004 ◽  
Vol 126 (2) ◽  
pp. 292-300 ◽  
Author(s):  
Luis San Andre´s ◽  
Oscar De Santiago
Keyword(s):  
Excitation Frequency ◽  
Air Entrainment ◽  
Forced Response ◽  
Effective Length ◽  
Single Frequency ◽  
Squeeze Film ◽  
Inertia Force ◽  
Damping Force ◽  
Squeeze Film Damper ◽  
Force Coefficients

Experimentally derived damping and inertia force coefficients from a test squeeze film damper for various dynamic load conditions are reported. Shakers exert single frequency loads and induce circular and elliptical orbits of increasing amplitudes. Measurements of the applied loads, bearing displacements and accelerations permit the identification of force coefficients for operation at three whirl frequencies (40, 50, and 60 Hz) and increasing lubricant temperatures. Measurements of film pressures reveal an early onset of air ingestion. Identified damping force coefficients agree well with predictions based on the short length bearing model only if an effective damper length is used. A published two-phase flow model for air entrainment allows the prediction of the effective damper length, and which ranges from 82% to 78% of the damper physical length as the whirl excitation frequency increases. Justifications for the effective length or reduced (flow) viscosity follow from the small through flow rate, not large enough to offset the dynamic volume changes. The measurements and analysis thus show the pervasiveness of air entrainment, whose effect increases with the amplitude and frequency of the dynamic journal motions. Identified inertia coefficients are approximately twice as large as those derived from classical theory.

Dynamics of axisymmetric bodies rising along a zigzag path

2008 ◽  
Vol 606 ◽  
pp. 209-223 ◽  
Author(s):  
PEDRO C. FERNANDES ◽  
PATRICIA ERN ◽  
FRÉDÉRIC RISSO ◽  
JACQUES MAGNAUDET
Keyword(s):  
Aspect Ratio ◽  
Transverse Direction ◽  
Transverse Velocity ◽  
Density Ratio ◽  
Transverse Component ◽  
The Body ◽  
Force Balance ◽  
Body Motion ◽  
Major Influence ◽  
Inertia Force

The forces and torques governing the planar zigzag motion of thick, slightly buoyant disks rising freely in a liquid at rest are determined by applying the generalized Kirchhoff equations to experimental measurements of the body motion performed for a single body-to-fluid density ratio ρs/ρf ≈ 1. The evolution of the amplitude and phase of the various contributions is discussed as a function of the two control parameters, i.e. the body aspect ratio (the diameter-to-thickness ratio χ = d/h ranges from 2 to 10) and the Reynolds number (100 < Re < 330), Re being based on the rise velocity and diameter of the body. The body oscillatory behaviour is found to be governed by the force balance along the transverse direction and the torque balance. In the transverse direction, the wake-induced force is mainly balanced by two forces that depend on the body inclination, i.e. the inertia force generated by the body rotation and the transverse component of the buoyancy force. The torque balance is dominated by the wake-induced torque and the restoring added-mass torque generated by the transverse velocity component. The results show a major influence of the aspect ratio on the relative magnitude and phase of the various contributions to the hydrodynamic loads. The vortical transverse force scales as fo = (ρf − ρs)ghπd2 whereas the vortical torque involves two contributions, one scaling as fod and the other as f1d with f1 = χfo. Using this normalization, the amplitudes and phases of the vortical loads are made independent of the aspect ratio, the amplitudes evolving as (Re/Rec1 − 1)1/2, where Rec1 is the threshold of the first instability of the wake behind the corresponding body held fixed in a uniform stream.

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