scholarly journals Numerical Model on the Dynamic Behavior of a Prototype Kaplan Turbine Runner

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ming Zhang ◽  
Qing-Guang Chen
Keyword(s):  
Experimental Results ◽  
Whole Body ◽  
Mode Shapes ◽  
Response Analysis ◽  
Kaplan Turbine ◽  
Turbine Runner ◽  
Narrow Frequency Band ◽  
Response Peak ◽  
Modal Behavior ◽  
Harmonic Response Analysis

Experimental and numerical investigations of the modal behavior of a prototype Kaplan turbine runner in air have been conducted in this paper. The widely used roving accelerometer method was used in the experimental modal analysis. A systematic approach from a single blade model to the whole runner has been used in the simulation to get a thorough understanding. The experimental results show that all the detected modes concentrate their displacements on the impacted blade. The numerical results show that the modes of the single blade form different mode families of the runner, and each mode family corresponds to a narrow frequency band. Harmonic response analysis shows that, at the response peak point, the single blade excitation can only get mode shapes with concentrations on the exciting blade due to the superposition of the close modes in each mode family, which explains the experimental results well, while the mode superposition can be avoided by the order excitation method. With the reduction of the connection stiffness between the blades and hub/control system, the frequencies of most modes change from insensitive to more and more sensitive to the connection stiffness change, which results in a sensitive area and an insensitive area. Through comparison with the experimental results, it is indicated that the natural frequencies of the runner can probably be predicted by merging the runner into a whole body.

The Harmonic Response Analysis of Engine Block Based on Modal Analysis

2011 ◽  
Vol 138-139 ◽  
pp. 246-251 ◽  
Author(s):  
Zhong Cai Zheng ◽  
Yan Gao ◽  
Na Liu ◽  
Kun Jin Zhang ◽  
Hai Ou Chen ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Modal Analysis ◽  
Engine Block ◽  
Mode Shapes ◽  
Response Analysis ◽  
Frequency Curve ◽  
Harmonic Response ◽  
Harmonic Response Analysis ◽  
Block Based ◽  
Typical Mode

The modal analysis of the engine block is carried out using finite element method. Through the analysis, the inherent frequencies and mode shapes of the first 6 order modes are obtained respectively. Then the harmonic response analysis of the engine block is carried out based on the modal analysis, and the corresponding inherent frequencies of the weak positions of block under the action of external cycle force are obtained. Finally, the consistency of the typical mode shape and amplitude-frequency curve is compared.

The Finite Element Analysis of Vibrating Screen

2011 ◽  
Vol 141 ◽  
pp. 134-138
Author(s):  
Chuan Guang Ding ◽  
Fang Zhen Song ◽  
Bo Song ◽  
Xiu Hua Men
Keyword(s):  
Large Scale ◽  
Natural Frequencies ◽  
Modular Design ◽  
Mode Shapes ◽  
Response Analysis ◽  
Element Analysis ◽  
Harmonic Response ◽  
Vibrating Screen ◽  
The Finite Element Analysis ◽  
Harmonic Response Analysis

The large-scale and modular design of vibrating screen brings about the trend that the screen separate from screen frame. The separation of the screen frame and the screen changes their dynamic characteristics. By making modal analysis and harmonic response analysis in ANSYS, the dynamic data of the screen and the screen frame was obtained, such as the natural frequencies, mode shapes, stress distribution and strain distribution. The results show that the stiffness of screen frame is higher than stiffness of the screen and the side plats and beams of screen are the weak parts.

Design and Tuning of the Ultrasonic Wide-Blade Horn for Joining and Cutting Non-Woven Fabrics

2014 ◽  
Vol 941-944 ◽  
pp. 1932-1936
Author(s):  
Chang Hee Lee ◽  
Jeong Seok Seo ◽  
Dong Sam Park
Keyword(s):  
Resonant Frequency ◽  
Vibration Amplitude ◽  
Woven Fabrics ◽  
Experimental Results ◽  
Cutting Process ◽  
Operating Frequency ◽  
Response Analysis ◽  
Harmonic Response ◽  
Output Surface ◽  
Harmonic Response Analysis

For joining and cutting non-woven fabrics, an ultrasonic wide-blade horn is expected to be used effectively. During the joining and cutting process, this horn can work as the punch in the punching and blanking systems. The performance of a wide-blade horn is normally relevant to the resonance at the operating frequency, the vibration amplitude, and the uniformity of the amplitude on the output surface. In this study, an ultrasonic wide-blade horn is optimally designed and fabricated for joining and cutting non-woven fabrics, and it is tuned to operate at 20 kHz, the resonant frequency of the converter. Analytic and experimental results show that based on the modal and harmonic response analysis and repeated tuning, the wide-blade horn could be optimally designed and fabricated. The resonant frequency of the developed horn was 19,979 Hz, and the amplitude uniformity of the output surface was 76%.

One Exciter per Sector Test Bench for Bladed Wheels Harmonic Response Analysis

2017 ◽  
Author(s):  
Leonardo Bertini ◽  
Paolo Neri ◽  
Ciro Santus ◽  
Alberto Guglielmo
Keyword(s):  
Test Bench ◽  
Wide Frequency Range ◽  
Mode Shapes ◽  
Response Analysis ◽  
Global Mode ◽  
Loop Control ◽  
Harmonic Response ◽  
Electromagnetic Devices ◽  
Modal Damping ◽  
Harmonic Response Analysis

Bladed wheel dynamic characterization is a crucial issue to avoid resonance excitations. The test bench presented in this paper was designed to independently excite the wheel sectors with one electromagnetic shaker each blade. Since a wide frequency range (1–10 kHz) is usually considered for bladed wheels, custom electromagnetic devices were designed, and then a closed-loop control software was also implemented. The global mode shapes of the wheel were then reconstructed through subsequent accelerometer measurements on all sectors to evaluate the harmonic response. The main target of the test rig is the reproduction of any operational condition by experimentally simulating an arbitrary number of stator vanes. In this way the response levels of the differently excited modes are measured and the modal damping is optimally quantified by providing a selective excitation of any number of nodal diameters. Preliminary results showed how the test setup actually allows to excite those modes with a specific number of nodal diameters, however, also exposed some difficulties to avoid small load components with different numbers of nodal diameters.

Double Nodal Diameter Spectrum Method and its Application in Quantification of Vibration Localization of Impellers With Splitter Blades

2017 ◽  
Author(s):  
Kaicheng Liu ◽  
Jianjun Wang
Keyword(s):  
Travelling Wave ◽  
Mode Shapes ◽  
Response Analysis ◽  
Nodal Diameter ◽  
Mode Localization ◽  
Vibration Localization ◽  
Engine Order ◽  
Vibration Pattern ◽  
Harmonic Response Analysis ◽  
Definition Of

Double nodal diameter spectrum (DNDS) method which is used to analyze nodal diameter (ND) components of the vibration modes of impellers with splitters is proposed and its application in quantification of mode localization has been studied. Firstly, ND characteristics of the typical impeller with splitter blades are analyzed by mode shapes and representative subeigenvectors. Secondly, DNDS method is proposed and DNDSs of the representative modes indicate that the tuned modes of impellers with splitter blades contain two ND components. By applying the simplified engine order (EO) excitation in the form of a travelling wave, harmonic response analysis has been carried out by which double nodal diameter vibration characteristics of the structure and the effectiveness of the DNDS method are both validated. Lastly, in terms of quantifying mode localization, the definition of mode localization factor (MLF) is improved based on DNDS. The numerical example proves that the pairing process of choosing the tuned mode corresponding to the mistuned one by utilizing both DNDS and the vibration pattern of blades when calculating the improved MLF could pick out the closest tuned mode to the mistuned one, which has a more explicit physical meaning.

scholarly journals FEM Based Modal and Harmonic Response Study of Stepped Shaft Having Cracks and Optimize Using ANN Method

2020 ◽  
pp. 1-12
Author(s):  
Asha Kumawat ◽  
K. B. Waghulde ◽  
Sanjay Kumawat
Keyword(s):  
Research Study ◽  
Fem Simulation ◽  
Mode Shapes ◽  
Response Analysis ◽  
Harmonic Response ◽  
Stepped Shaft ◽  
Harmonic Response Analysis ◽  
The Stability ◽  
Ss 304

In the present research study, modal and harmonic response analysis is performed for a stepped shaft made of SS-304 material using the FEM simulation technique. In the present study crack effect is also considered to find the role of cracks during modal analysis. Total six mode shapes are considered in this study and 500 N force is considered for harmonic response analysis. The simulation is performed using Ansys WB based APDL solver. The main outcome for this study is the critical speed of shaft for rotation from 10 RPM to 80K RPM, stress, deformation of the shaft without crack, and with crack. The selected shaft is stepped in nature, total length of shaft is 300 mm having three diameters of 20 mm, 40 mm, and 60 mm. The natural frequency for all six node shapes is from 1000 Hz to 4000 Hz having deformation from 15 mm to 30 mm approx for all combinations of crack in the shaft. After all simulation it is found that for all mode shapes, the stability and strength of the shaft are good during vibration conditions.

A novel modal calculation method of 1-D phononic crystal band gap

2015 ◽  
Vol 11 (1) ◽  
pp. 16-22
Author(s):  
Lei Li ◽  
Qing Liu
Keyword(s):  
Band Gap ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Mode Shapes ◽  
Response Analysis ◽  
Content Type ◽  
Existence Conditions ◽  
Harmonic Response Analysis ◽  
Modal Method

Purpose – The purpose of this paper is to propose a modal method to calculate the band gaps of one-dimensional (1D) phononic crystals. Design/methodology/approach – The phononic crystals have modes with exponential form envelope in the band gaps, however, outside the band gaps the modes are of amplitude modulation periodic form. Thus the start and end frequencies of band gaps can be determined from the existence conditions of periodic modes. So, the band gaps calculation of 1D phononic crystal is transformed into the existence discussion of periodic solution of mode shapes equation. The results are verified by finite element harmonic response analysis. Findings – At the start and end frequencies of the band gap, the mode equation have solution with period of lattice constant. Originality/value – Compared with the traditional theoretical methods, the proposed modal method has a clearer principle and easier calculation.

scholarly journals A Dual Frequency Ultrasonic Cleaning Tank Developed by Transient Dynamic Analysis

2021 ◽  
Vol 11 (2) ◽  
pp. 699
Author(s):  
Worapol Tangsopa ◽  
Jatuporn Thongsri
Keyword(s):  
High Performance ◽  
Acoustic Pressure ◽  
Single Frequency ◽  
Response Analysis ◽  
Dual Frequency ◽  
Transient Dynamic Analysis ◽  
Ultrasonic Cleaning ◽  
Calculational Method ◽  
Successful Design ◽  
Harmonic Response Analysis

At present, development of manufacturer’s ultrasonic cleaning tank (UCT) to match the requirements from consumers usually relies on computer simulation based on harmonic response analysis (HRA). However, this technique can only be used with single-frequency UCT. For dual frequency, the manufacturer used information from empirical experiment alongside trial-and-error methods to develop prototypes, resulting in the UCT that may not be fully efficient. Thus, lack of such a proper calculational method to develop the dual frequency UCT was a problem that greatly impacted the manufacturers and consumers. To resolve this problem, we proposed a new model of simulation using transient dynamics analysis (TDA) which was successfully applied to develop the prototype of dual frequency UCT, 400 W, 18 L in capacity, eight horn transducers, 28 and 40 kHz frequencies for manufacturing. The TDA can indicate the acoustic pressure at all positions inside the UCT in transient states from the start to the states ready for proper cleaning. The calculation also reveals the correlation between the positions of acoustic pressure and the placement positions of transducers and frequencies. In comparison with the HRA at 28 kHz UCT, this TDA yielded the results more accurately than the HRA simulation, comparing to the experiments. Furthermore, the TDA can also be applied to the multifrequency UCTs as well. In this article, the step-by-step development of methodology was reported. Finally, this simulation can lead to the successful design of the high-performance dual frequencies UCT for the manufacturers.

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