High frequency scattering properties of focused acoustic beams helpful for finite element research

2011 ◽  
Vol 130 (4) ◽  
pp. 2332-2332
Author(s):  
Philip L. Marston
Keyword(s):  
Finite Element ◽  
High Frequency ◽  
Acoustic Beams

Enhanced Vibration Control of Ultrasonic Tooling Using Finite Element Analysis

1991 ◽  
Author(s):  
Kevin O’Shea
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Sections ◽  
High Frequency ◽  
Excellent Correlation ◽  
Accurate Identification ◽  
Element Analysis ◽  
Optimum Configuration ◽  
Slot Length ◽  
Design Variables

Abstract The use of finite element analysis (FEA) in high frequency (20–40 kHz), high power ultrasonics to date has been limited. Of paramount importance to the performance of ultrasonic tooling (horns) is the accurate identification of pertinent modeshapes and frequencies. Ideally, the ultrasonic horn will vibrate in a purely axial mode with a uniform amplitude of vibration. However, spurious resonances can couple with this fundamental resonance and alter the axial vibration. This effect becomes more pronounced for ultrasonic tools with larger cross-sections. The current study examines a 4.5″ × 6″ cross-section titanium horn which is designed to resonate axially at 20 kHz. Modeshapes and frequencies from 17–23 kHz are examined experimentally and using finite element analysis. The effect of design variables — slot length, slot width, and number of slots — on modeshapes and frequency spacing is shown. An optimum configuration based on the finite element results is prescribed. The computed results are compared with actual prototype data. Excellent correlation between analytical and experimental data is found.

scholarly journals A human skin ultrasonic imaging to analyse its mechanical properties

2009 ◽  
pp. 105-116
Author(s):  
Alexandre Delalleau ◽  
Gwendal Josse ◽  
Jérôme George ◽  
Yassine Mofid ◽  
Frédéric Ossant ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
High Frequency ◽  
Complex Structure ◽  
Mechanical Parameters ◽  
High Frequency Ultrasound ◽  
Specific Procedure ◽  
Complex Behaviour ◽  
Behaviour Law ◽  
Frequency Ultrasound

The analysis of the skin mechanical behaviour is a key-point for different field of investigation. As the skin is a complex structure, studies are usually based on inverse methods that compare experimental and finite element numerical results. Besides the considered behaviour law, one of the most important question concerns the geometrical aspects of the skin tissue. In this paper, it is shown how high frequency ultrasound imaging helps the calculation of skin mechanical parameters. The hypodermis influence is firstly discussed through elastographic analyses. A specific procedure to measure the dermis thickness is then proposed to highlight that such a measurement must be considered to draw reliable conclusions. The obtained results are finally discussed to point out the interest of such simplifications for the study of more complex behaviour laws.

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