A method for modal vibration control of elastic systems using additional vibrators called `wave-trapped horns' is proposed. Experimental verification the has been done several vibrating tools whose shapes are often adopted in ultrasonic plastic welding. The validity confirmed.

Ultrasonic motors using longitudinal and torsional motions of rod vibrators have previously been proposed. Several motor constructions, whose forms are different from the previous ones, proposed their characteristics experimentally examined in order to develop ultrasonic this type; that is, they expected much uses, according how modified. Two groups dealt with: one contains basically suited relatively high torque 2-3 kgf-cm other for small or medium below about 1.0 kgf-cm. As result,...

A method for modal vibration control of elastic systems using additional vibrators called ‘‘wave-trapped horns’’ is proposed. Experimental verification the has been done many large ultrasonic tools whose shapes are often adopted in plastic welding. Uniform amplitude distributions have realized at radiating faces tools. Effects both thickness and number horns also investigated, with bending found to diminish effectiveness method. The validity finally confirmed under certain conditions.

Excitation of a progressive wave in straight and thin bar vibrating the flexural mode can be utilized to construct transport device such as parts-feeder. A new method excite is proposed herein which has been proved possible by simulation experiment. without utilizing concept impedance matching transmission line done using two adjacent modes vibration.

The authors have observed the accumulation of frost on surface a rectangular aluminum alloy (duralumin) plate flexurally vibrating at approximately 37 kHz in an atmosphere almost 100% relative humidity 2°C. surface, which had been prepolished with abrasive slurry for maintaining its average roughness about 100 nm, was refrigerated temperature -20°C cold carbon-dioxide gas as coolant. Experiments conducted and without fine silver oxide powder spread so to examine effect artificial ice crystal...

Bolt-clamped Langevin-type transducers (BLTs) are widely used as powerful vibration sources in high-power ultrasonic applications. In the structure of a BLT, static compressional prestress is imposed on piezoelectric ceramic elements by clamping, to compensate for their weakness tensile stress. Nevertheless, no report has been made about clamping effects characteristics BLT with reasonable estimation prestress. Previous works material property change ceramics caused stress have always...

The authors have observed the accumulation of frost on surface a rectangular duralumin plate (20 mm/spl times/92.6 mm) flexurally vibrating approximately at 37 kHz in atmosphere almost 100% relative humidity 2 degree temperature. surface, which got refrigerated temperature down to -20 with cool carbon-dioxide gas experiments, had been ground advance abrasive slurry (thick water suspension carborundum) such that its average roughness was maintained about 100 nm. Experiments were conducted and...

Bolt-clamped Langevin-type transducers (BLTs) used in high-power ultrasonics are required to realize various characteristics depending on the technical field where they used. Specifically for high amplitude operation, static prestress or bearing stress imposed piezoelectric elements transducer by clamping should be large enough compensate their low tensile strength. The authors previously calculated finite element method (FEM), but numerical results have not been experimentally confirmed yet...

Abstract We propose a piezoelectric transformer comprising two identical bolt-clamped Langevin-type transducers (BLTs) and stepped horn for its applications to high-power electronics. The can realize specified step-up voltage transformation ratio determined by the cross-sectional area of horn, both ends which are connected BLTs, at driving frequency in vicinity mechanical resonance frequency. In experiments, we obtained results predicted finite-element analysis. deviations measured...

We have identified a crucial point for realization of high mechanical quality factor (Q) bolt-clamped Langevin-type transducer used to excite large torsional vibrations cylindrical system. A sufficient margin the static bearing stress over vibratory shearing one at interface between components has been found necessary Q as result some numerical simulations and experiments two models transducers. hollow shape is seen great advantage in this respect.

Water tree degradation in XLPE cables used for under-ground distribution or transmission lines is a serious problem. Some diagnostic methods to detect water have been developed, but the sensitivity of them not sufficient 22 kV/66 kV class cables. The reason that conventional are based on detecting signals from trees bridged over insulation layer. In case cables, even unbridged will be harmful because their higher operating stress, so there demands highly reliable new such We found generates...

Bolt-clamped Langevin-type transducers (BLTs) are common vibration sources in high-power ultrasonic applications such as plastic joining. In this paper, the authors propose a low-aspect-ratio BLT shape based on numerical solutions of complex elastic contact problem concerning bearing stress (prestress) imposed interfaces between parts by clamping with screw bolt. The prestress distribution at interface has significant influence mechanical quality factor (Q) BLT. It is found that pitch bolt...

Bolt-clamped Langevin-type transducers (BLTs) are widely used in various fields of industrial application high-power ultrasonics. One the most crucial points designing a transducer this type is estimation bearing stress imposed by clamping on interface between metal block and piezoelectric element. This prestress, which compensates for low tensile strength materials used, must be larger than dynamic vibratory at components high-amplitude operation. Precise it virtually impossible, owing to...

Heat generation caused by high-amplitude ultrasonic vibrations at the interface has long been believed to be most dominant factor for mechanism of plastic joining. However, authors have not found any conspicuous thermal effects in experiments joining thin very low density polyethylene (VLDPE) films using torsional vibrations. In process joining, temperature two VLDPE 0.1 mm thickness increased up 73 °C only and no trace melting material observed this under a polarizing microscope....

We have previously developed a hollow cylindrical bolt-clamped Langevin-type transducer with high mechanical quality factor ( Q ) for excitation of high-amplitude torsional vibrations. In this paper, we propose construction vibrating systems that comprise `stepped horn' (a transformer vibration) and the stumpy `twisting' by us. The distinctive feature is it achieves compactness without sacrificing volume piezoelectric ceramics important high-power ultrasonic applications. Through...

We propose a low-frequency piezoelectric transformer comprising two identical bolt-clamped Langevin-type transducers (BLTs) and stepped horn with half-wavelength straight extension. The can realize specified step-up voltage transformation ratio as determined by the cross-sectional area of whose both ends BLTs are connected to, driving frequency at which is realized be set near its mechanical resonance. Thus, it mechanically held firmly vibratory node without affecting vibration mode or...

The authors previously determined that thermal effects are not a dominant factor in the ultrasonic joining of very low density polyethylene (VLDPE) films using torsional vibration. Now, to confirm plastic materials "melted" by mechanically generated heat joining, they have conducted experiments for thin poly(ethylene terephthalate) (PET) films. temperature at interface two PET 0.1 mm thickness only increased approximately 100 °C, and no trace liquidation material was observed under...

In inspection of structural members buildings using the ultrasonic time-of-flight computed tomography (TOF CT) system previously developed by authors, reconstructed images did not always reflect their internal states appropriately, since no consistent technique for determination TOF signals had been clearly established yet. Hence, authors have proposed "squared amplitude integral method" now. numerical simulations wave propagation in circular cross sections 24 cm diameter, values obtained...

A new ultrasonic device for feeding powder with the use of a hollow acrylic cylinder, on which an axisymmetric progressive elastic wave is excited, has previously been proposed. Its characteristics have also reported. To find vibrational behaviors cylinder powder, elliptic particle movement inside surface was analyzed. The authors found many forms motion. Some them can move objects toward vibration source, as expected, but, contrary, others in propagation direction.

Abstract The peculiar events called the “jumping and dropping” phenomena of piezoelectric ceramic vibrators in high amplitude operation have been widely known. phenomena, that occur solely vicinity mechanical resonance frequencies vibrators, are due to emergence hysteresis frequency domain with an abrupt increase decrease vibratory amplitude. It has long believed nonlinearity materials is dominant cause unstable behaviors. Nevertheless, authors found they can be attributed local polarization...

Motivation: In compressed sensing, it is impossible to separate folded-over images using equally spaced under-sampled signal when the subject a real-valued image. Goal(s): Our goal was enable image reconstruction signal, and generalize phase-varied images. Approach: Amplitude modulation in phase-encoding direction makes folded complex-valued thus facilitates separation of overlapping space. Results: The successful up speedup factor 4 with U-Net. Phase were successfully reconstructed by...

The heat generation mechanism in ultrasonic welding by a torsional vibrator is discussed based on simple theory of viscoelasticity. It concluded that the principal source torsion friction loss at interface, not viscous dissipation. However, near resonant frequency, which much higher than practical frequencies, dissipation becomes main cause generation. Optimum conditions are also discussed. A loose interface and non-slip anvil preferable for welding. present discussions will contribute to...