scholarly journals Study on dynamic characteristics of leaf spring system in vibration screen

2021 ◽  
pp. 146134842110229
Author(s):  
Jiacheng Zhou ◽  
Chao Hu ◽  
Ziqiu Wang ◽  
Zhengfa Ren ◽  
Xiaoyu Wang ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Vertical Direction ◽  
Maximum Amplitude ◽  
Exciting Force ◽  
Mode Shapes ◽  
Leaf Spring ◽  
Amplification Factors ◽  
Simulation And Experiment ◽  
Exciting Forces ◽  
Spring System

By studying dynamic characteristics of the leaf spring system, a new elastic component is designed to reduce the working load and to a certain extent to ensure the linearity as well as increase the amplitude in the vertical and horizontal directions in vibration screen. The modal parameters, amplitudes, and amplification factors of the leaf spring system are studied by simulation and experiment. The modal results show that the leaf spring system vibrates in horizontal and vertical directions in first and second mode shapes, respectively. It is conducive to loosening and moving the particles on the vibration screen. In addition, it is found that the maximum amplitude and amplification factor in the horizontal direction appear at 300 r/min (5 Hz) while those in the vertical direction appear at 480 r/min (8 Hz), which are higher than those in the disc spring system. Moreover, the amplitude of the leaf spring system increases proportionally with the increase of exciting force while the amplification factors are basically the same under different exciting forces, indicating the good linearity of the leaf spring system. Furthermore, the minimum exciting force occurs in the leaf spring system under the same amplitude by comparing the exciting force among different elastic components. The above works can provide guidance for the industrial production in vibration screen.

scholarly journals Study on Dynamic Characteristics of the Disc Spring System in Vibration Screen

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Jiacheng Zhou ◽  
Chuzhe Zhang ◽  
Ziqiu Wang ◽  
Kuanmin Mao
Keyword(s):  
Natural Frequency ◽  
Vertical Direction ◽  
Maximum Amplitude ◽  
Exciting Force ◽  
Third Order ◽  
The Third ◽  
Simulation And Experiment ◽  
Exciting Forces ◽  
Spring System ◽  
Disc Spring

To avoid too large exciting force in traditional linear vibrating screen and unstable working state in resonance screen, the disc spring system is applied in the linear vibration screen. The model of the disc spring system in vibration screen is established by simulation and experiment. The characteristics of modal and amplitude of the disc spring system in vibration screen are studied. We found that the disc spring system vibrates in vertical direction at the third-order natural frequency, which is consistent with the direction of the vibration screen when screening particles. Moreover, the third-order natural frequencies in simulation and experiment are basically consistent. Furthermore, the maximum amplitude of the disc spring system appears at 960 r/min (16 Hz), which is in accord with the third-order natural frequency. Meanwhile, the amplitude increases proportionally with the increase of exciting force, while the amplification factors are the same under three different exciting forces. This indicates that the disc spring system has excellent linearity. The results of research provide guidance for design and application of elastic components on the vibration screen.

scholarly journals A Study on the Influence of Different Constraint Modes and Number of Disc Springs on the Dynamics of Disc Spring System

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jiacheng Zhou ◽  
Chuzhe Zhang ◽  
Ziqiu Wang ◽  
Kuanmin Mao ◽  
Xiaoyu Wang
Keyword(s):  
Amplification Factor ◽  
Maximum Amplitude ◽  
Assembly Process ◽  
Good Consistency ◽  
Before And After ◽  
Simulation And Experiment ◽  
Spring System ◽  
The Relationship ◽  
Maximum Amplification ◽  
Disc Spring

In this work, the influences of constraint modes and the number of disc springs on the dynamic characteristics of the disc spring system are studied by simulation and experiment. The amplitudes and amplification factors of the disc spring system under different constraint modes and different numbers of disc springs are obtained. The results show that the maximum amplitude and amplification factor both appear at the constraint modes of locking and no preloading, which indicates that the locking and no preloading is the best constraint mode among the four different constraint modes. Moreover, the amplitude of the disc spring system first increases and then decreases with the number of disc springs increasing, while the amplification factor increases with the number of disc springs increasing. The maximum amplification factor (10.21 in experiment) of the disc spring system appears at 10 disc springs. By studying the relationship between the number of disc springs and amplification factor and damping, we find that the damping of the disc spring system can be reduced by increasing the disc spring numbers, and thus, the corresponding amplification factor can be improved. Furthermore, as the number of disc spring increases, the height differences of disc springs before and after locking are all close to 3 mm, which indicates that the amount of locking compression in the assembly process has a good consistency when the number of disc springs changes. The aforementioned works can provide guidance for the industrial production in screen vibration.

Analysis and Optimization of the Static and Dynamic Characteristics of Head Frame

2011 ◽  
Vol 418-420 ◽  
pp. 2055-2059 ◽  
Author(s):  
Yu Lin Wang ◽  
Na Jin ◽  
Kai Liao ◽  
Rui Jin Guo ◽  
Hu Tian Feng
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Maximum Stress ◽  
Dynamic Performance ◽  
Mode Shapes ◽  
Cnc Machine ◽  
Static And Dynamic Characteristics ◽  
Maximum Deformation ◽  
Improvement Measures ◽  
Optimal Measure

The head frame is a key component which plays a supportive and accommodative role in the spindle system of CNC machine tool. Improving the static and dynamic characteristics has profound significance to the development of machine tool and product performance. The simplified finite element modal is established with ANSYS to carry out the static and modal analysis. The results showed that the maximum deformation of the head frame was 0.0066mm, the maximum stress was 3.94Mpa, the deformation of most region was no more than 0.0007mm, which all verified that the head frame had a good stiffness and deforming resistance; several improvement measures for dynamic performance were also proposed by analyzing the mode shapes, and the 1st order natural frequency increased 7.33% while the head frame mass only increased 1.58% applying the optimal measure, which improved the dynamic characteristics of the head frame effectively.

Dynamic Model and Simulation of Flag Vibrations Modeled as a Membrane

2014 ◽  
Author(s):  
Gary Frey ◽  
Ben Carmichael ◽  
Joshua Kavanaugh ◽  
S. Nima Mahmoodi
Keyword(s):  
Constant Velocity ◽  
Cross Flow ◽  
Vertical Direction ◽  
Equation Of Motion ◽  
Mode Shapes ◽  
System Response ◽  
Wind Flow ◽  
Pressure Function ◽  
Model And Simulation ◽  
Reasonable Model

A flag is modeled as a membrane to investigate the two-dimensional characteristics of the vibration response to an uniform wind flow. Both the affecting tension and pressure functions for the wind flow with constant velocity are introduced and utilized in the modeling. In this case, the tension is caused by the weight of the flag. The pressure function is a function describing the pressure variations caused on the flag when in uniform flow. The pressure function is found by assuming that the air flow is relatively slow and that the flag is wide enough to minimize cross flow at the boundaries. An analysis of the downstream motion of the flag is necessary as well. Hamilton’s principle is employed to derive the partial differential equation of motion. The flag is oriented in the vertical direction to neglect the effect of the flag’s weight on the system’s response. Galerkin’s method is used to solve for the first four mode shapes of the system, and the system response is numerically solved. Simulations reveal a very reasonable model when the flag is modeled as a membrane.

scholarly journals Research on dynamic characteristics of plate under pedestrian excitation based on Newmark-β

2018 ◽  
Vol 37 (4) ◽  
pp. 682-699
Author(s):  
Xinfang Ge ◽  
Weirong Wang ◽  
Wei Yuan
Keyword(s):  
Rectangular Plate ◽  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Great Influence ◽  
Interaction Model ◽  
Vertical Direction ◽  
Structural Vibration ◽  
Normal Walking ◽  
Plate Structure ◽  
Pedestrian Excitation

Development of micro and ultra-precision machining, precision instruments and equipment, precision assembly and testing has put forward more and more high requirements to vibration isolation on environmental elements, especially the pedestrian excitation generated by workers' normal walking. Therefore, it is very important to study the pedestrian excitation's influence on vibration characteristics of precision instruments and equipment. In this study, dynamic model including mathematical model of pedestrian excitation, interaction model between pedestrian and rectangular plate structure, the human–plate coupled dynamic equation in vertical direction of pedestrian–plate structure was established. And then we use the Newmark-β method to solve the time-domain step-by-step integration of the first four order modes' dynamic equations and study the influence of the linear notion trajectory along the central axis direction on the dynamic characteristics of the rectangular plate. By simulation, we discussed plate structure response under different conditions, including plate structure displacement and acceleration response under the single person excitation with different velocities, under normal walking velocity with different number of pedestrians and under this case of different distance between two pedestrians. The results show that the structural vibration induced by pedestrian excitation has great influence on dynamic characteristics of plate.

Dynamic characteristics of horizontally curved bridges

2017 ◽  
Vol 24 (19) ◽  
pp. 4465-4483 ◽  
Author(s):  
Mohsen Amjadian ◽  
Anil K Agrawal
Keyword(s):  
Free Vibration ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Response Spectrum ◽  
Translational Motion ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Curved Bridges ◽  
Horizontally Curved ◽  
Horizontally Curved Bridges

Horizontally curved bridges have complicated dynamic characteristics because of their irregular geometry and nonuniform mass and stiffness distributions. This paper aims to develop a simplified and practical method for the calculation of the natural frequencies and mode shapes of horizontally curved bridges that would be of interest to bridge engineers for the estimation of the seismic response of these types of bridges. For this purpose, a simple three-degree-of-freedom (3DOF) dynamic model for free vibration equation of this type of bridge has been developed. It is shown that the translational motion of the deck of horizontally curved bridges in the direction that is perpendicular to their axis of symmetry is always coupled with the rotational motion of the deck, regardless of the location of the stiffness center. The model is further exploited to develop closed-form formulas for the estimation of the maximum displacements of the corners of the deck of one-way asymmetric horizontally curved bridges. The accuracy of the model is verified by finite-element model of a horizontally curved bridge prototype in OpenSEES. Finally, the model is utilized to study the influence of the location of the stiffness center with respect to the deck curvature center on the natural frequency and the maximum displacements of the corners of the deck for different curvatures of the deck. The results of free vibration analysis show that the natural frequencies of one-way asymmetric horizontally curved bridges, in general, increase with the increase of the subtended angle of the deck. The results of earthquake response spectrum analysis show that the increase in the subtended angle of one-way asymmetric horizontally curved bridges decreases the radial displacements of the corners of the deck but increases the azimuthal displacement. These two responses both increase with the increase in the distance between the stiffness center and the curvature center.

A Study on the Effect of Bird Hit Damage on the Dynamic Response of Aero-Engine Fan Blade

2013 ◽  
Author(s):  
Hithesh Channegowda ◽  
Raghu V. Prakash ◽  
Anandavel Kaliyaperumal
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Foreign Object Damage ◽  
Aero Engine ◽  
Need To Evaluate ◽  
Bird Impact ◽  
Post Impact ◽  
Fan Blade ◽  
Critical Components

Fan blades of an aero-engine assembly are the critical components that are subjected to Foreign Object Damage (FOD) such as bird impact. Bird impact resulting in deformation damage onto set of blades, which in turn alters the blade mass and stiffness distribution compared to undamaged blades. This paper presents the numerical evaluation of dynamic characteristics of bird impact damaged blades. The dynamic characteristics evaluated are the natural frequencies and mode shapes of post impact damaged set of blades and the results are compared with undamaged set of blades. The frequencies and mode shapes are evaluated for the damaged blades, with varying angles of bird impact and three blade rotational speeds. Study reveals that first bending and torsional frequencies of deformed blades are significantly affected compared to undamaged set of blades. Study emphasize the need to evaluate the natural frequencies deformed blades, that has direct bearing on High Cycle Fatigue (HCF) life of the blade, to ensure post damaged blades operate safely for certain time to reduce inflight accidents and safe landing.

Uvula Dynamic Characteristics

2013 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
S. Ashaat ◽  
B. A. Martin ◽  
R. Heinzer ◽  
J. Haba Rubio ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Structural Model ◽  
Fluid Layer ◽  
Structural Characteristics ◽  
Upper Airway ◽  
Mode Shapes ◽  
Tissue Elasticity ◽  
Upper Airways ◽  
Obstructive Sleep ◽  
Mri Scans

The airway binary fluid layer and the structural characteristics of the upper airways have significant influence on the activity of the airway muscles by changing airway compliance and collapsibility during obstructive sleep apnea trauma. The uvula plays an important role in the collapse process. Using MRI scans, this paper develops a structural model for the uvula and determines its dynamic characteristics in terms of natural frequencies and mode shapes as a preliminary process to determine optimum conditions to therapeutically relieve upper airway obstruction. The effect of the variation of tissue elasticity due to water content is elaborated on.

scholarly journals Effect of Processing Parameters on the Dynamic Characteristic of Material Extrusion Additive Manufacturing Plates

2019 ◽  
Vol 9 (24) ◽  
pp. 5345
Author(s):  
Shijie Jiang ◽  
Yinfang Shi ◽  
Yannick Siyajeu ◽  
Ming Zhan ◽  
Chunyu Zhao ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Theoretical Model ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Processing Parameters ◽  
Combination Method ◽  
Mode Shapes ◽  
Material Extrusion ◽  
Function Combination

Material extrusion (ME), an additive manufacturing technique, can fabricate parts almost without geometrical limitations. With the growing application of ME parts, especially in actual working conditions, the dynamic characteristics are needed to be studied to accurately determine their reliability. This study provides an experimental validation of the theoretical model for predicting the dynamic characteristics of ME plates fabricated with three different key processing parameters, i.e., extrusion width, layer height and build direction. The model is set up based on the bidirectional beam function combination method, and a series of experimental tests are performed. It is found that different processing parameters result in the material properties of the samples to vary, thus leading to different dynamic characteristics. Through the comparison between predictions and measurements, it is shown that the influencing trend of the processing parameters is predicted precisely. The theoretical model gives reliable predictions in dynamic characteristics of ME plates. The natural frequency discrepancy is below 13.4%, and the predicted mode shapes are the same as the measured ones. This present work provides theoretical basis and technical support for further research in improving the dynamic performance of ME products, and helps extend the applications of this technique.

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