Vibration characteristics analysis of disordered two-span beams with numerical and experimental methods

2017 ◽  
Vol 24 (16) ◽  
pp. 3641-3657 ◽  
Author(s):  
Shenglin Zhou ◽  
Fengming Li ◽  
Chuanzeng Zhang
Keyword(s):  
Time History ◽  
Frequency Equation ◽  
Vibration Characteristics ◽  
Experimental Investigations ◽  
Superposition Method ◽  
The Finite Element Method ◽  
Response Curves ◽  
Modal Superposition Method ◽  
Characteristics Analysis ◽  
Good Agreement

Numerical and experimental investigations on the vibration behaviors of the disordered two-span beams have been conducted. The dynamics model of the two-span beam is established and solved by means of the modal superposition method. According to the boundary conditions, the frequency equation of the two-span beam is obtained, and the natural frequencies, vibration modes, frequency response curves, and time-history responses of the structure are also obtained consequently. Considering the structural size disorder due to the two different sub-span lengths of the two-span beam, a disorder ratio is introduced in terms of the two sub-span lengths and its influences on the vibration characteristics of the structure are analyzed. By comparing the results from numerical calculation with those from the finite element method (FEM) and experiments, good agreement is observed, which verifies the validity of the present investigations.

Prediction for Sound Radiated Power from Submerged Double Cylindrical Shells Based on Measuring Vibration of Inner Shell

2013 ◽  
Vol 779-780 ◽  
pp. 602-606 ◽  
Author(s):  
Chao Zhang ◽  
De Jiang Shang ◽  
Qi Li
Keyword(s):  
Prediction Error ◽  
Cylindrical Shells ◽  
Prediction Method ◽  
Superposition Method ◽  
Power Curve ◽  
Mean Square ◽  
Average Prediction Error ◽  
Radiated Power ◽  
Modal Superposition Method ◽  
Good Agreement

A prediction method for the sound radiated power from submerged double cylindrical shells based on measuring vibration of inner shell is presented. The prediction model of submerged double cylindrical shells is established by using modal superposition method. Applied the ratio of the measuring value and theoretical value of the acceleration in one point or mean square velocity of inner shell, and combined with the theoretical value of the sound radiated power, the predicted value of the sound radiated power is derived. The corresponding experiment is carried out in lake. And then the measuring power curve is compared with the predicted power curve based on this method. The result shows that they have good agreement and the average prediction error is less than 2dB.

scholarly journals Modelling of Guillotine Cutting of a Cold-Rolled Steel Sheet

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2954 ◽  
Author(s):  
Jarosław Kaczmarczyk
Keyword(s):  
Steel Sheet ◽  
Cutting Process ◽  
Experimental Investigations ◽  
Rolled Steel ◽  
The Finite Element Method ◽  
Cold Rolled Steel ◽  
Cold Rolled ◽  
Cutting Processes ◽  
Professional Tool ◽  
Good Agreement

In this paper, the modelling of a cutting process of a cold-rolled steel sheet using a symmetrical cutting tool is presented. The fast-changing nonlinear dynamic cutting process was elaborated by means of the finite element method and the computer system LS-DYNA. Experimental investigations using scanning electron microscopy were performed and the results are presented in this work. The numerical results were compared with experimental ones. The comparison shows a good agreement between the results obtained by means of numerical modelling and those received from experimental investigations. The numerical simulations of the cutting process and the experimental investigations aimed to understand the mechanism of the cutting process. They serve as a highly professional tool for carrying out research investigating the behavior of complex nonlinear fast-changing dynamical cutting processes in the future.

The Vibration Characteristics Analysis of Ship Foundation Based on the Arrangement of Isolators

2011 ◽  
Vol 55-57 ◽  
pp. 2202-2205
Author(s):  
Yu Wang ◽  
Xing Lin Chen ◽  
Guang Min Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequency ◽  
Vibration Characteristics ◽  
Force Characteristic ◽  
The Finite Element Method ◽  
Foundation Vibration ◽  
Characteristics Analysis ◽  
Excitation Force ◽  
General Connection

Contrary to the general connection style, the vibration characteristics of the ship foundation vibration is researched under the arrangement style of isolators acted on it. And the influence of the parameters of rigidity and damp to the excitation force characteristic is studied too. Based on the real ship data and the finite element method, the study is shown that the excitation force from the device to the foundation is not only related to the rigidity, damp of isolators and the natural frequency of device-isolator-foundation system but also the related to arrangement style of isolator. When the excited frequency is lower it had little effect on the vibration characteristics relatively. However that the frequency is higher, it had significant effect on the vibration.

Identification of Vehicle-Bridge Interactive Forces From Measured Bridge Responses: Theoretical Studies

1995 ◽  
Author(s):  
S. S. Law ◽  
Tommy H. T. Chan ◽  
Q. H. Zeng
Keyword(s):  
Time History ◽  
Bending Moment ◽  
Highway Bridges ◽  
Interaction Force ◽  
Superposition Method ◽  
Vibration Data ◽  
Moving Force ◽  
Modal Superposition Method ◽  
History Of ◽  
Bridge Responses

Abstract Information of the vehicle-bridge interaction force is an important parameter in the design and evaluation of highway bridges. However it is difficult to directly measure or accurately calculate the force which is a moving force. The objective of this paper is to explore the theory of force identification based on the response of the structure to acquire a time history of the moving force. The force will be identified in time domain using a modal superposition method. A moving force on a simply supported beam is simulated, and the computational results show that the method is noise sensitive, and yet acceptable results can be obtained by combining the use of vibration data of the bending moment and acceleration measurements.

scholarly journals Study on Vibration Characteristics of Marine Centrifugal Pump Unit Excited by Different Excitation Sources

2021 ◽  
Vol 9 (3) ◽  
pp. 274
Author(s):  
Cui Dai ◽  
Yuhang Zhang ◽  
Qi Pan ◽  
Liang Dong ◽  
Houlin Liu
Keyword(s):  
Centrifugal Pump ◽  
Calculation Model ◽  
Vibration Characteristics ◽  
Superposition Method ◽  
Pump Unit ◽  
Electromagnetic Excitation ◽  
Main Frequency ◽  
Vibration Excitation ◽  
Modal Superposition Method ◽  
Vibration Mechanism

In order to study the vibration mechanism of a marine centrifugal pump unit and explore the contribution of vibration caused by different vibration excitation sources, a marine centrifugal pump with a specific speed of 66.7 was used for research. A numerical calculation model of the flow field and electromagnetic field of the pump unit was established to analyze the frequency spectrum characteristics and contribution of pump unit vibration caused by different excitation sources. Using the modal superposition method, the vibration characteristics of the pump unit caused by fluid excitation and electromagnetic excitation were analyzed. The results show that the main frequency of pump unit vibration caused by fluid excitation was at the 1× blade passing frequency. The main frequency of pump unit vibration caused by electromagnetic excitation was at the 2× utility frequency. The contribution of different excitation sources to the vibration of marine centrifugal pump unit was in the following order: fluid excitation on the inner surface of the pump > electromagnetic excitation > fluid excitation in the impeller.

Effects of different cooling conditions on friction stir processing of A356 alloy: Numerical modeling and experiment

2021 ◽  
pp. 095440622110456
Author(s):  
Mostafa Akbari ◽  
Parviz Asadi
Keyword(s):  
Wear Resistance ◽  
Temperature Distribution ◽  
Simulation Model ◽  
Material Flow ◽  
A356 Alloy ◽  
Experimental Investigations ◽  
Air Cooling ◽  
The Finite Element Method ◽  
Friction Stir ◽  
Good Agreement

In the present work, the effects of in-process cooling are investigated on the material flow, temperature distribution, axial force, wear resistance, and microstructural and mechanical properties of friction stir processed (FSPed) Al-Si aluminum alloy. The finite element method (FEM) was developed for modeling the process, based on the eulerian-lagrangian technique, and then verified by the experimental force and temperature histories. Next, the material flow and temperature distribution during the friction stir process (FSP) with in-process cooling under different conditions were considered. After that, the experimental investigations, including the optical microscopy, hardness, and wear tests, were conducted. Finally, the stir zone (SZ) shape obtained by experiments and simulation model were compared for the FSPed samples without cooling and with air cooling. The material flow achievements reveal that using a coolant affects the material flow in the pin-driven zone more significantly than in the shoulder-driven zone, leading the SZ to change from the basin shape into the V shape. The SZ shapes obtained from the experiments and the simulation model show a good agreement between the shapes of the samples FSPed without cooling and with air cooling. Moreover, experimental results showed that using in-process cooling reduces Si particles' size and thus significantly increases the hardness and wear resistance. The Si particles size is reduced from 10 μm in the base metal to 2.6 μm and 2 μm in the air-cooled and water-cooled samples. Consequently, the wear mass loss reduced almost 28% and 40%, and hardness increased almost 35% and 80% for the air-cooled and water-cooled samples compared to the processed samples without coolant.

A Directional Converter of Longitudinal Vibration with One Input and Multiple Outputs

2019 ◽  
Vol 105 (5) ◽  
pp. 753-758
Author(s):  
He Xiping ◽  
Zhang Haidao
Keyword(s):  
Finite Element Method ◽  
Longitudinal Vibration ◽  
Frequency Equation ◽  
Vibration Modes ◽  
Excitation Voltage ◽  
The Finite Element Method ◽  
Resonant Frequencies ◽  
Multiple Outputs ◽  
Input And Output ◽  
Good Agreement

Traditional power ultrasonic vibration systems can process one object at one time and only have one output. A directional converter of longitudinal vibration with multiple outputs composed of an input rod, a hemispherical vibrator, and three output rods is presented. The frequency equation used in the design is derived with free edges at the input and output ends of the converter, as well as the continuity of displacements, forces, and angles of rotation at each component junction. The resonant frequencies of three fabricated converters designed using the proposed method are in good agreement with those from the finite element method and also with tested values. With the input end of the converter joined with a piezoelectric transducer with a resonant frequency of 19.8 kHz, the longitudinal vibration modes and displacement amplitudes of the output ends of the three converters at their resonant frequencies are tested. The results show that longitudinal vibration can be transferred from the input end to the multi-output ends through the converter. Furthermore, there exists a linear relationship between the excitation voltage and the displacements of each output of the converter.

Vibration Characteristics Analysis of an Elastic Cavity

2015 ◽  
Vol 775 ◽  
pp. 9-13
Author(s):  
Man Kang ◽  
Jing Lu
Keyword(s):  
Structural Design ◽  
Present Method ◽  
Integration Method ◽  
Vibration Characteristics ◽  
The Finite Element Method ◽  
Equilibrium Equations ◽  
Precise Integration ◽  
Design And Optimization ◽  
Characteristics Analysis ◽  
Relationship Of

A semi-analytical method was proposed to analyze the vibration characteristics of an elastic cavity. Combining the precise integration method and bent theory of the beam, the transfer relationship of the ends of the beam was derived. Based on the displacement continuity conditions and equilibrium equations of the junction, the conversion relation of the beams was also established. Then, the dynamics control equations of an elastic cavity were assembled by the above relationship and boundary conditions. The comparison with the FEM had verified the accuracy of the present method. This method avoids the shortage that the calculation accuracy over-depends on the element types and the mesh dividing methods, which is existed in the finite element method. In addition to this, the process of this method is efficient, so it is a useful method to the structural design and optimization of the cavity.

scholarly journals Modelling and Microstructural Aspects of Ultra-Thin Sheet Metal Bundle Cutting

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 162 ◽  
Author(s):  
Jarosław Kaczmarczyk ◽  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Sebastian Sławski
Keyword(s):  
Thin Sheet ◽  
Thin Metal ◽  
Experimental Investigations ◽  
The Finite Element Method ◽  
Metal Sheets ◽  
Fracture Area ◽  
Thin Sheet Metal ◽  
Simulation Results ◽  
Scanning Electron ◽  
Good Agreement

The results of numerical simulations of the cutting process obtained by means of the finite element method were studied in this work. The physical model of a bundle consisting of ultra-thin metal sheets was elaborated and then submitted to numerical calculations using the computer system LS-DYNA. Experimental investigations rely on observation of metallographic specimens of the surfaces being cut under a scanning electron microscope. The experimental data showing the microstructure of an ultra-thin metal bundle were the basis for the verification of the numerical results. It was found that the fracture area consists of two distinct zones. Morphological features of the brittle and ductile zones were identified. There are distinct differences between the front and back sides of the knife. The experimental investigations are in good agreement with the simulation results.

scholarly journals Dynamic analysis of sandwich beam with viscoelastic core under moving loads

Mechanika ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 325-330
Author(s):  
Sabiha Tekili ◽  
Youcef KHADRI ◽  
Yacine KARMI
Keyword(s):  
Sandwich Beam ◽  
Numerical Approach ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Integration Scheme ◽  
Superposition Method ◽  
Moving Loads ◽  
The Finite Element Method ◽  
Modal Superposition Method ◽  
Viscoelastic Core

In this article, numerical approach is proposedfor dynamic behavior of symmetrical sandwich beams with viscoelastic core under movingload using the Hamilton's principle formulation and the finite element method solution. The dynamic responses are obtained for different configurations using the modal superposition method and the implicit Newmark integration scheme. The analysis shows that the viscoelastic damping has a significant effect on the vibration behavior involving the improvement of the damping of the structure. The parametric study of the effect of the configuration parameters shows that the sandwich structure has more dissipative capacities of vibratory energy by adopting adequate configurations to the structure.

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