Harmonic excitation response of standard ultrasonic horn designs for machining nomex honeycomb core composite
Ultrasonic horn plays a vital role in achieving vibration amplitude at tool end (VATE) by enhancing output displacement of piezoelectric ultrasonic transducer suitable for efficient machining of advanced composites. Higher vibration amplitude enhances ultrasonic machining quality, surface integrit...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Penerbit Universiti Kebangsaan Malaysia
2024
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| Online Access: | http://journalarticle.ukm.my/25123/ http://journalarticle.ukm.my/25123/1/06.pdf |
| Summary: | Ultrasonic horn plays a vital role in achieving vibration amplitude at tool end (VATE) by enhancing output
displacement of piezoelectric ultrasonic transducer suitable for efficient machining of advanced composites.
Higher vibration amplitude enhances ultrasonic machining quality, surface integrity and dimensional accuracy of
Nomex honeycomb composite (NHC) while reducing cutting forces. Furthermore, low stress concentrations allow
ultrasonic tool to have more safety factor and longevity. Ultrasonic horn is designed to enhance displacement
amplitude of piezoelectric ultrasonic transducer and get optimum VATE while keeping stresses in acceptable limits
to avoid failure at very high operating frequency of ultrasonic machining system. In this research, variety of standard
ultrasonic horns (SUH) were designed with same length and end diameters; and were tested under similar operating
conditions, using finite element method. The ultrasonic actuation of the horn exploits the first axial mode of horn
vibration. Harmonic response analysis was carried out to determine axial modal frequencies (AMF), VATE,
stresses, and factor of safety for performance evaluation. VATE attained by step horn was found to be greatest
among all other SUHs for frequency ratio greater than one, but may be prone to early failure due to high stress
concentrations. VATE achieved by third order Bezier, Gaussian, exponential, catenoidal, conical and second order
Bezier horns were found less than that of step horn by 11.7 %, 16.6 %, 16.7 %, 17 %, 16.73 % and 18 % respectively.
However, 44.2 %, 43.43 %, 42.5 %, 43.5 %, 42.8 % and 37.67 % reduction of stresses was achieved by Gaussian,
exponential, catenoidal, conical, second and third order Bezier horns respectively. Outcomes of present work would
be beneficial for designers, researchers, scientists, and manufacturers of ultrasonic machine tool to select appropriate
SUH designs according to requirements. |
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