Numerical Design of Stepped Compound Horn with Longitudinal-Torsional Vibration under Single Acoustic Excitation

2014 ◽  
Vol 621 ◽  
pp. 385-391
Author(s):  
Jian Xin Zheng ◽  
Jie Han ◽  
Chuan Shao Liu
Keyword(s):  
Acoustic Wave ◽  
Torsional Vibration ◽  
Longitudinal Vibration ◽  
Design Procedure ◽  
Geometrical Parameters ◽  
Acoustic Excitation ◽  
Test Results ◽  
Acoustic Wave Propagation ◽  
Element Analysis ◽  
Geometrical Dimensions

The mechanism of longitudinal-torsional vibration (LTV) realized by using converter with multiple diagonal slits (MDS) was analyzed based on the acoustic wave propagation when acoustic wave enters obliquely from steel to air. The influences of geometrical parameters of the stepped compound horn with multiple diagonal slits on natural frequencies of LTV were studied with finite element analysis (FEA). The design procedure of stepped compound horn with LTV was provided. The vibration characteristics of actual horn were analyzed with simulation and test. The FEA results show that LTV of the output end of the stepped compound horn may be realized when the input end is excited by longitudinal vibration at certain natural frequency if suitable geometrical dimensions are selected, and the amplitude of the horn is periodical; the trajectory of the particle in the output end is helical curve. The test results indicate that LTV may be realized by stepped compound horn under single acoustic excitation, and the vibration frequency is close to the simulation result, and its vibration properties are good. This method may be applied to design the acoustics system of ultrasonic machining with LTV under single acoustic excitation.

Realization of Longitudinal-Torsional Complex Vibration by Conical Compound Horn under Single Acoustic Excitation

2012 ◽  
Vol 522 ◽  
pp. 251-255
Author(s):  
Jian Xin Zheng
Keyword(s):  
Circular Cylinder ◽  
Torsional Vibration ◽  
Longitudinal Vibration ◽  
Engineering Application ◽  
Wave Theory ◽  
Acoustic Excitation ◽  
Ultrasonic Machining ◽  
Numerical Example

Realization of longitudinal-torsional complex vibration by conical compound horn has more engineering application value with respect to the conventional longitudinal-torsional complex vibration converting devices. The frequency equations of longitudinal vibration and torsional vibration for the conical compound horn made up of cone and circular cylinder were given based on the wave theory of longitudinal vibration and torsional vibration of ultrasonic horn. The mechanism of the realization of longitudinal-torsional complex vibration by conical compound horn under single acoustic excitation was explained. And a numerical example indicated that longitudinal-torsional complex vibration could be realized by conical compound horn when the length and diameter of such horn were well chosen. The results of this study may be used in the field of longitudinal-torsional complex vibration ultrasonic machining.

scholarly journals A Contribution to the Study of the Design of an Industrial Centrifugal Compressor

1984 ◽  
Author(s):  
K. D. Papailiou ◽  
G. Bois
Keyword(s):  
Centrifugal Compressor ◽  
Design Procedure ◽  
Test Results ◽  
Interesting Point ◽  
Axial Part ◽  
Starting Point ◽  
Compressor Design ◽  
The Impact ◽  
Geometrical Dimensions ◽  
New Machine

The present work has had as a starting point an already existing high hub/tip ratio industrial centrifugal compressor design. An effort was undertaken to design a first new machine using theoretical methods, keeping, however, the overall geometrical dimensions, issued from the experience of the industry. The new design was manufactured and tested. The test results were found to be rather good, compared with the current industrial experience. Additionally, a second new design was undertaken which had as aim to diminish the axial part length, leaving untouched the hub/tip ratio. If this effort was successful, it would mean that the length of the shaft for a multistage arrangement could be diminished and, thus the need for such a high hub/tip ratio, resulting from the shaft diameter. It was found, actually, possible to reduced the axial length of the inducer by a factor of two, approximately. The second new design was manufactured and the resulting machine, when tested, was found to have the same performances as the first new design. A rather interesting point of the whole design procedure was the fact that a boundary layer calculation method was used in the blade-to-blade surface, which could take into account the influence of the Coriolis force and blade curvature on turbulence. The impact of this influence on the whole design was found to be decisive. The calculation procedure, the two designs and the overall test rests are described in the present work.

A Study on Design of Ultra-Precision Micro-Feed Stage

2006 ◽  
Vol 315-316 ◽  
pp. 131-135
Author(s):  
Q. Zhang ◽  
Ze Sheng Lu
Keyword(s):  
Design Method ◽  
Dynamic Performance ◽  
Design Procedure ◽  
Performance Parameters ◽  
Element Analysis ◽  
Flexure Hinges ◽  
Ultra Precision ◽  
Positioning Technique ◽  
Precision Machines ◽  
Geometrical Dimensions

Ultra-precision positioning technique has become one of the important parts in the development of precision machines. Flexure stage driven by piezoelectric actuator (PZT) has been used widely as micro-feed installation because they have many advantages, such as: driving directly, fine displacement resolution, no friction or spacing. This paper designed a micro-feed stage driven by PZT using clinograph mechanism, analyzed the influence of flexure hinges on the static and dynamic performance of micro-feed stage based on finite element analysis. The design procedure was presented by which we can determine the geometrical dimensions of flexure hinge easily and achieve desired performance parameters of the stage, and the effectiveness of the design method was validated by experiment.

Simulation of Noise Attenuation Using One and Two Degree of Freedom Helmholtz Resonators in Pipelines

2012 ◽  
Author(s):  
Maaz Farooqui ◽  
Samir Mekid
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Acoustic Wave ◽  
Degrees Of Freedom ◽  
Design Procedure ◽  
Experimental Results ◽  
Noise Attenuation ◽  
Acoustic Wave Propagation ◽  
Helmholtz Resonators ◽  
Two Degree Of Freedom

Helmholtz resonators are known to be efficient resonators for ducts if they are properly designed. A design procedure is suggested in this paper to identify the size of the resonators in one and two degrees of freedom. The procedure is supported by a through numerical simulation of acoustic wave propagation that is presented and is verified using published experimental results. The overall procedure shows achievable great attenuation of noise in pipeline.

scholarly journals Acoustic Wave Propagation in Air-Filled Pipes Using Finite Element Analysis

2018 ◽  
Vol 8 (8) ◽  
pp. 1318 ◽  
Author(s):  
Mustapha Abdullahi ◽  
S Oyadiji
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wave Propagation ◽  
Acoustic Wave ◽  
Wave Velocity ◽  
Acoustic Wave Propagation ◽  
Element Analysis ◽  
Hexahedral Elements ◽  
Element Type ◽  
3D Solid

The major objective of this work is to develop an efficient Finite Element Analysis (FEA) procedure to simulate wave propagation in air-filled pipes accurately. The development of such a simulation technique is essential in the study of wave propagation in pipe networks such as oil and gas pipelines and urban water distribution networks. While numerical analysis using FEA seems superficially straight forward, this paper demonstrates that the element type and refinement used for acoustic FEA have a significant effect on the accuracy of the result achieved and the efficiency of the computation. In particular, it is shown that the well-known, better overall performance achieved with 3D solid hexahedral elements in comparison with 2D-type elements in most stress and thermal applications does not occur with acoustic analysis. In this paper, FEA models were developed taking into account the influence of element type and sizes using 2D-like and 3D element formulations, as well as linear and quadratic nodal interpolations. Different mesh sizes, ranging from large to very small acoustic wavelengths, were considered. The simulation scheme was verified using the Time of Flight approach to derive the predicted acoustic wave velocity which was compared with the true acoustic wave velocity, based on the input bulk modulus and density of air. For finite element sizes of the same order as acoustic wavelengths which correspond to acoustic frequencies between 1 kHz and 1 MHz, the errors associated with the predictions based on the 3D solid hexahedral acoustic elements were mostly greater than 15%. However, for the same element sizes, the errors associated with the predictions based on the 2D-like axisymmetric solid acoustic elements were mostly less than 2%. This indicates that the 2D-like axisymmetric solid acoustic elements are much more efficient than the 3D hexahedral acoustic elements in predicting acoustic wave propagation in air-filled pipes, as they give higher accuracies and are less computationally intensive. In most stress and thermal FEA, the 3D solid hexahedral elements are much more efficient than 2D-type elements. However, for acoustic FEA, the results show that 2D-like axisymmetric elements are much more efficient than 3D solid hexahedral elements.

A new stiffness-strength-relationship-based design approach for global buckling prevention of buckling-restrained braces

2020 ◽  
pp. 136943322097478
Author(s):  
Wen-Hao Pan ◽  
Jing-Zhong Tong
Keyword(s):  
Design Procedure ◽  
Design Criterion ◽  
Design Approach ◽  
Design Solution ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Buckling Restrained Braces ◽  
Global Buckling ◽  
Target Design ◽  
Strength Relationship

This paper proposes a new stiffness-strength-relationship-based design approach that can pinpoint the target design solution for steel buckling-restrained braces (BRB). First, a stiffness–strength requirement interaction curve (the design criterion) with a very simple and easy-to-use form is derived based on a second-order analysis. This interaction curve clearly illustrates the opposing stiffness and strength requirements of the restraining system. Second, based on the geometrical parameters and material properties, a stiffness–strength relationship curve of the BRB restraining system is established. This second relationship curve is expressed by a linear function for a uniform steel BRB. By using the two analytical curves, the point of intersection defines the target design point. A straightforward design procedure for steel BRBs is then developed. A design example of steel BRBs is considered to demonstrate this easy-to-use design procedure for obtaining economical BRB designs. The design is verified and discussed by a rigorous finite element analysis.

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