Effect of mechanical vibrations of ultrasonic frequency on the structure of St. 45 steel

The article discusses the most important original achievements in the use of high-power mechanical vibrations with low and ultrasonic frequency in various welding processes such as MIG, MAG, TIG, RW, LW, diffusion welding and brazing in relation to various basic materials such as structural steel and aluminum alloys. Mechanical vibrations were introduced by means of ultrasonic vibrating systems and using the shot-blasting process, as well as acoustic influence. As part of the comparative research, the structure and hardness analysis of HV0.1 was presented. The obtained results indicate that both low-frequency and ultrasonic frequency vibrations significantly change the properties of the resulting structures affected by mechanical vibrations. The scale of these changes varies depending on the frequency and parameters specific to each of the welding processes used. The obtained results allow us to conclude that the skillful application of mechanical vibrations accompanying welding processes can contribute to the reduction of grain sizes, to change the depth or width of penetration and to lowering hardness in the sensitive heat affected zone area.

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RESEARCH RESPONSE QUENCHER MECHANICAL VIBRATIONS BY THE FORMULA Of CARDANO

Scientific Herald of Uzhhorod University Series Physics ◽

10.24144/2415-8038.2013.33.181-185 ◽

2013 ◽

Vol 33 (0) ◽

pp. 181-185

Author(s):

М. І. Ігнатишин ◽

І. Д. Рубіш

Keyword(s):

Mechanical Vibrations

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EVALUATION OF THE EXPOSURE OF WHEELCHAIR USERS TO MECHANICAL VIBRATIONS: A COMPARATIVE STUDY OF MANUAL AND MOTORIZED CHAIRS ON PUBLIC FLOORS

10.26678/abcm.cobem2019.cob2019-0365 ◽

2019 ◽

Author(s):

Willian Favero Menegatt ◽

GIOVANNI BRATTI

Keyword(s):

Comparative Study ◽

Mechanical Vibrations ◽

Wheelchair Users

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Воздействиеультразвуковогополянадинамическуювязкостьводы

Vodosnabzhenie i sanitarnaia tehnika ◽

10.35776/mnp.2019.09.04 ◽

2019 ◽

pp. 27-29

Author(s):

P. Vikulin ◽

K. Khlopov ◽

M. Cherkashin

Keyword(s):

Dynamic Viscosity ◽

Experimental Studies ◽

Ultrasonic Field ◽

Maximum Effect ◽

Ultrasonic Frequency ◽

Ultrasonic Vibrations ◽

Wastewater Disposal ◽

Laboratory Setup ◽

Sonic Treatment ◽

The Impact

Enhancing water purification processes is provided by various methods including physical ones, in particular, exposure to ultrasonic vibrations. The change in the dynamic viscosity of water affects the rate of deposition of particles in the aquatic environment which can be used in natural and wastewater treatment. At the Department Water Supply and Wastewater Disposal of the National Research Moscow State University of Civil Engineering experimental studies were conducted under laboratory conditions to study the effect of ultrasound on the change in the dynamic viscosity of water. A laboratory setup has been designed consisting of an ultrasonic frequency generator of the relative intensity, a transducer (concentrator) that transmits ultrasonic vibrations to the source water, and sonic treatment tanks. Experimental studies on the impact of the ultrasonic field in the cavitation mode on the dynamic viscosity of the aqueous medium were carried out the exposure time was obtained to achieve the maximum effect.Интенсификация процессов очистки воды осуществляется с помощью различных методов, в том числе и физических, в частности воздействием ультразвуковых колебаний. Изменение динамической вязкости воды влияет на скорость осаждения частиц в водной среде, что может быть использовано в процессах очистки природных и сточных вод. На кафедре Водоснабжение и водоотведение Национального исследовательского Московского государственного строительного университета в лабораторных условиях проведены экспериментальные исследования по изучению влияния ультразвука на изменение динамической вязкости воды. Разработана схема лабораторной установки, состоящая из генератора ультразвуковых частот с соответствующей интенсивностью, преобразователя (концентратора), передающего ультразвуковые колебания в исходную воду, и емкости для озвучивания. Выполнены экспериментальные исследования по влиянию ультразвукового поля в режиме кавитации на динамическую вязкость водной среды, получено время экспозиции для достижения максимального эффекта.

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Usability of Ultrasonic Frequency Testing for Rapid Generation of High and Very High Cycle Fatigue Data

Materials ◽

10.3390/ma14092245 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2245

Author(s):

Michael Fitzka ◽

Bernd M. Schönbauer ◽

Robert K. Rhein ◽

Niloofar Sanaei ◽

Shahab Zekriardehani ◽

...

Keyword(s):

Strain Rate ◽

High Cycle Fatigue ◽

Fatigue Properties ◽

Ultrasonic Frequency ◽

Cycle Fatigue ◽

Reinforced Polymer ◽

Very High Cycle Fatigue ◽

Ultrasonic Fatigue ◽

Fibre Reinforced Polymer ◽

Very High

Ultrasonic fatigue testing is an increasingly used method to study the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) properties of materials. Specimens are cycled at an ultrasonic frequency, which leads to a drastic reduction of testing times. This work focused on summarising the current understanding, based on literature data and original work, whether and how fatigue properties measured with ultrasonic and conventional equipment are comparable. Aluminium alloys are not strain-rate sensitive. A weaker influence of air humidity at ultrasonic frequencies may lead to prolonged lifetimes in some alloys, and tests in high humidity or distilled water can better approximate environmental conditions at low frequencies. High-strength steels are insensitive to the cycling frequency. Strain rate sensitivity of ferrite causes prolonged lifetimes in those steels that show crack initiation in the ferritic phase. Austenitic stainless steels are less prone to frequency effects. Fatigue properties of titanium alloys and nickel alloys are insensitive to testing frequency. Limited data for magnesium alloys and graphite suggest no frequency influence. Ultrasonic fatigue tests of a glass fibre-reinforced polymer delivered comparable lifetimes to servo-hydraulic tests, suggesting that high-frequency testing is, in principle, applicable to fibre-reinforced polymer composites. The use of equipment with closed-loop control of vibration amplitude and resonance frequency is strongly advised since this guarantees high accuracy and reproducibility of ultrasonic tests. Pulsed loading and appropriate cooling serve to avoid specimen heating.

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Optimization of Ultrasonic-Assisted Extraction, Characterization, and Antioxidant Activities of Polysaccharides From Sojae Semen Praeparatum

Natural Product Communications ◽

10.1177/1934578x211020622 ◽

2021 ◽

Vol 16 (5) ◽

pp. 1934578X2110206

Author(s):

Yongshuai Jing ◽

Ruijuan Zhang ◽

Lan Li ◽

Danshen Zhang ◽

Yu Liu ◽

...

Keyword(s):

Antioxidant Activities ◽

Deae Cellulose ◽

Chemical Compositions ◽

Hydroxyl Groups ◽

Ultrasonic Frequency ◽

Ultrasonic Power ◽

Assisted Extraction ◽

Ultrasonic Time ◽

Ultrasonic Assisted ◽

Ultrasonic Assisted Extraction

In this study, response surface methodology (RSM) was used to optimize the ultrasonic-assisted extraction parameters of Sojae Semen Praeparatum polysaccharides (SSPP-80), the optimum conditions were determined as follows: ultrasonic frequency of 100 W, ultrasonic power of 80 Hz, ultrasonic temperature of 52℃, ultrasonic time of 23 minutes, and liquid to raw material ratio of 40 mL/g. Based on these conditions, polysaccharides extraction rate was 7.72% ± 0.26%. Then, 2 novel polysaccharides (SSPP-80‐1, SSPP-80‐2) were isolated from SSPP by DEAE-cellulose 52 chromatography. The chemical compositions, physicochemical properties, and structure of SSPPs were investigated by simultaneous thermal analyzer (TGA), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FI-IR), and high-performance liquid chromatography (HPLC). The results showed that SSPP-80 and 2 fractions were mainly composed of mannose (Man), glucose (Glc), galactose (Gal), xylose (Xyl), and arabinose (Ara). In addition, the antioxidant activities were evaluated against the DPPH and hydroxyl radical in vitro, the IC50 of SSPP-80, SSPP-80‐1 and SSPP-80‐2 against DPPH free radical were 4.407, 8.267, and 5.204 mg/mL, respectively, whereas the IC50values for removing hydroxyl groups were 5.318, 3.516, and 4.016 mg/mL, respectively. It demonstrated that SSPP-80 and 2 fractions had certain antioxidant activity. Theoretical basis for use of Sojae Semen Praeparatum polysaccharides was provided by this study.

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Model approach for electromagnetically excited mechanical vibrations in direct-drive wind turbines

Journal of Physics Conference Series ◽

10.1088/1742-6596/1618/2/022060 ◽

2020 ◽

Vol 1618 ◽

pp. 022060

Author(s):

Christoph Mülder ◽

Tobias Duda ◽

Georg Jacobs ◽

Kay Hameyer

Keyword(s):

Wind Turbines ◽

Direct Drive ◽

Mechanical Vibrations ◽

Model Approach

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The effect of vibratory conditioning on tensile strength and microstructure of 1018 mild steel

World Journal of Engineering ◽

10.1108/wje-07-2020-0296 ◽

2020 ◽

Vol 17 (6) ◽

pp. 837-844 ◽

Cited By ~ 1

Author(s):

Venkata Suresh Bade ◽

Srinivasa Rao P. ◽

Govinda Rao P.

Keyword(s):

Tensile Strength ◽

Mild Steel ◽

Fusion Zone ◽

Dc Motor ◽

Grain Structure ◽

Internal Stresses ◽

Skilled Workers ◽

Mechanical Vibrations ◽

Content Type ◽

Weld Defects

Purpose The purpose of this paper is to investigate the prominence of mechanical excitations at the time of welding. In the past years, the process of welding technology has expanded its influence in manufacturing. The crucial drawback of conventional welding is prompted by internal stresses and distortions, which is the focal reason for weld defects. These weld defects can be diminished by the process called post-weld heat treatment (PWHT), which consumes more working hours and needs skilled workers. To replace these PWHT processes, mechanical vibrations are introduced during the process of welding to diminish these weld defects. Design/methodology/approach In the current research, the mechanical vibrations are transferred to weld-pool through vibro-motor and DC motor connected to the electrode. As per standards, the tensile test specimens were prepared for welding with different voltages of vibro-motor and DC motor respectively. The weld joints were tested for tensile strength and analyzed the microstructure at the fusion zone. Findings Melt-ability at fusion zone of 1018 mild steel was investigated by the single-stroke intense heat process of fusion welding. It is observed that the mechanical vibrations technique has a profound influence on the enhancement of the fusion zone characteristics and grain structure. The peak value of the tensile strength is observed at 100 s of vibration, 190 V of vibro-motor voltage and 18 V of electrode voltage. The tensile strength of the welded joints with vibrations is increased up to 22.64% when it is compared with conventional welding. The enhancement of the tensile strength of the weld bead was obtained because of the formation of fine grain structure. So, mechanical vibrations are identified as the most convenient method for improving the mild steel alloys weld quality. Originality/value A novel approach called mechanical vibrations during the process of welding is implemented for fusion zone refinement.

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