Faculty Profiles - TSUCHIKAWA, Satoru

Papers - TSUCHIKAWA, Satoru

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Vibration Characteristics of a Rotating Circular Saw III. Non-limear vibration and coupled vibration Reviewed

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 776 1993

Vibration Characteristics of a Rotating Circular Saw IV. Non-linear resonant frequency Reviewed

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 783 1993

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .3. NONLINEAR VIBRATION AND COUPLED VIBRATION Reviewed

YOKOCHI H, TSUCHIKAWA S, KIMURA S

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 776 - 782 1993

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .4. NONLINEAR RESONANT-FREQUENCY Reviewed

YOKOCHI H, TSUCHIKAWA S, KIMURA S

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 783 - 787 1993

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .3. NONLINEAR VIBRATION AND COUPLED VIBRATION Reviewed

H YOKOCHI, S TSUCHIKAWA, S KIMURA

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 776 - 782 1993

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

A circular saw of slightly imperfect axial symmetry has two normal modes with slightly different natural frequencies. The purpose of this report was to clarify the fundamental non-linear vibration, coupled vibration, and the phase angle of the two vibrations, theoretically, and experimentally.
The following results were obtained:
1. The circular saw oscillated non-linearly with increases in membrane stress when the amplitude became large. The excited frequency at maximum amplitude was higher than a linear natural frequency, and the frequency range at large amplitudes became wide, and the amplitude collapsed after the maximum amplitude. A hysteresis phenomenon was induced upon increasing the excitation frequency and reducing it. The two vibrations were coupled when the amplitudes were large.
2. In the theoretical analysis, the two frequency responses were entirely different, in the case where the excitation frequency increased from the intermediate frequency between the two natural frequencies and in the case where it increased from the frequency that was lower than the lower natural frequency.
3. The coupled vibrations were excited, with the decrease of the interval between the two natural frequencies.
4. In the experimental analysis, under only the single excited frequency, the vibration with the natural frequency different than the exciting frequency became coupled to the exciting vibration with the phase angle +/-pi/2, when the amplitude became large.
5. Under the two excited vibrations, simultaneously with any phase angle between the two exciting forces, the phase angle between the two responding displacements converged +/-pi/2, and the two vibrations became coupled when the vibrations were excited non-linearly. As the phase angle between the two exciting forces closed to +/-pi/2, the coupled vibrations were excited in a wide range of frequencies.
6. With the rotating disk, it was considered that in the case where the exciting frequency equaled the backward traveling wave frequency, the vibration with the higher natural frequency predominated, and, in the case where the exciting frequency equaled the forward traveling wave frequency, the vibration with the lower natural frequency predominated.

Web of Science

VIBRATION CHARACTERISTICS OF A ROTATING CIRCULAR-SAW .4. NONLINEAR RESONANT-FREQUENCY Reviewed

H YOKOCHI, S TSUCHIKAWA, S KIMURA

MOKUZAI GAKKAISHI Vol. 39 ( 7 ) page： 783 - 787 1993

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

Two types of coupled vibrations with the identical number of nodal diameters were excited during variable rotation speeds. One type (Mode I) was that the vibration was excited at slower rotation speeds, the amplitudes of the backward traveling wave predominated, and the phase angle between the two vibrations equaled -pi/2. The other type (Mode 111) was that the vibration was excited at faster rotation speeds, the amplitude of the forward traveling wave predominated, and the time phase angle equaled pi/2. The purpose of this report is to clarify the characteristics of non-linear vibration in the two types of coupled vibrations by measuring the saw-based frequencies and the amplitudes during the variable rotation speeds.
The following results were obtained:
1. With the rotation speed, the resonance frequency curve of Mode I differed from that of Mode III.
2. For each Mode, in the relationship between the compensation resonant frequencies that subtracted an increased frequency by the centrifugal stress from the original frequency and the amplitudes, the ideal and non-linear frequency response curve occurred without the jumping phenomena where the amplitudes rapidly increased and decreased. Under the vibration exciting by the forces based on air-vortex shedding, the frequencies of the air-vortex shedding had synchronized with the frequencies of the circular saw, and the excitation frequency changed like a self-excitation vibration in dependence on the vibration amplitude of a circular saw.
3. In the case of Mode III, the start frequency was lower than the lower natural frequency. The resonance frequencies were decided by the non-linear frequency response of the vibration of the lower natural frequency. The two vibrations became coupled with the same non-linear frequency response.
4. In the case of Mode I, the start frequency was higher than the higher natural frequency. The vibration of the higher natural frequency mainly was excited, and the resonance frequencies were decided by the non-linear frequency response of the vibration of the higher natural frequency.

Web of Science

Application of Near Infrared Spectrophotometry to Wood I. Effects of the surface structure Reviewed

MOKUZAI GAKKAISHI Vol. 38 ( 2 ) page： 128 1992

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO WOOD .1. EFFECTS OF THE SURFACE-STRUCTURE Reviewed

TSUCHIKAWA S, HAYASHI K, TSUTSUMI S

MOKUZAI GAKKAISHI Vol. 38 ( 2 ) page： 128 - 136 1992

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO WOOD .1. EFFECTS OF THE SURFACE-STRUCTURE Reviewed

S TSUCHIKAWA, K HAYASHI, S TSUTSUMI

MOKUZAI GAKKAISHI Vol. 38 ( 2 ) page： 128 - 136 1992

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

Near infrared spectrophotometry (NIRS) is a non-destructive analytical method to determine the composition of materials. Diffuse reflectance or an absorption spectrum over 800-2500 nm allows clear distinguishing of various organic compounds.
In this report, the effects of the surface structure of wood on the absorption of NIR rays are examined to take full advantage of this method. In the experiments, sitka spruce (Picea sitchensis (Bong.) Carr.), which had various surface roughnesses and orientations of the fibers in the direction of incident light, was used. The results are summarized as follows: (1) Absorbance decreases as the orientation of the fibers to the direction of incident light theta is increased. Such a tendency is more pronounced as the wavelength of interest becomes longer.
(2) The absorbance decreases with increasing surface roughness R'(max). A decrease in theta, or an increase in wavelength, raises the sensitivity of absorbance to R'(max). The relationship between absorbance and the surface roughness of wood can be expressed by the exponential equation labelled as the first empirical equation. Two constants in the equation depend on the wavelength and theta.
(3) Increasing the wavelength decreases the minimum thickness of the board in which light is completely diffuse-reflected. It is important to select the proper wavelength depending on the surface depth of interest.
(4) A semi-theoretical equation, labelled as the second empirical equation, is derived from a newly-proposed optical model, and it measures the values of absorbance. This model is composed of a theoretically equivalent membrane to the surface asperities and inclined square tubes of tracheids. It becomes clear that the thickness of the equivalent membrane should be some multiple of the maximum height of the surface roughness, and the amount of diffusely reflected light from the surface of the lumen is strongly dependent on theta and the wavelength.
(5) NIRS becomes a useful method for the detection of the physical conditions of wood.

Web of Science

Application of Near Infrared Spectrophotometry to the Determination of Fiber Orientation and Moisture Content of Wood. Reviewed

MOKUZAI GAKKAISHI Vol. 37 ( 8 ) page： 758 1991

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO THE DETERMINATION OF FIBER ORIENTATION AND MOISTURE-CONTENT OF WOOD Reviewed

TSUCHIKAWA S, HAYASHI K, TSUTSUMI S

MOKUZAI GAKKAISHI Vol. 37 ( 8 ) page： 758 - 760 1991

APPLICATION OF NEAR-INFRARED SPECTROPHOTOMETRY TO THE DETERMINATION OF FIBER ORIENTATION AND MOISTURE-CONTENT OF WOOD Reviewed

S TSUCHIKAWA, K HAYASHI, S TSUTSUMI

MOKUZAI GAKKAISHI Vol. 37 ( 8 ) page： 758 - 760 1991

Characteristics of the Vibration of Disks with Model Teeth and the Flows around the Disks I. Reviewed

MOKUZAI GAKKAISHI Vol. 36 ( 11 ) page： 936 1990

CHARACTERISTICS OF THE VIBRATION OF DISKS WITH MODEL TEETH AND THE FLOWS AROUND THE DISKS .1. RATIOS OF SPACE TO WIDTH OF SQUARE POLES Reviewed

YOKOCHI H, TSUCHIKAWA S, KIMURA S

MOKUZAI GAKKAISHI Vol. 36 ( 11 ) page： 936 - 943 1990

CHARACTERISTICS OF THE VIBRATION OF DISKS WITH MODEL TEETH AND THE FLOWS AROUND THE DISKS .1. RATIOS OF SPACE TO WIDTH OF SQUARE POLES Reviewed

H YOKOCHI, S TSUCHIKAWA, S KIMURA

MOKUZAI GAKKAISHI Vol. 36 ( 11 ) page： 936 - 943 1990

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPAN WOOD RES SOC

In our study, the characteristics of the vibration of a disk with model teeth, which were square poles, and the flow around the disk were investigated. Diameter and thickness of the disk were 305 mm and 2 mm, respectively. Width and height of square poles were 2 mm and 8 mm, respectively. The rotation speed was changed at intervals of 1 rps from 30 rps to 60 rps. The ratio (s/w) of the spaces (s) between the square poles and the widths (w) of the square poles ranged from 0.6 to 238.5.
The flow around the disk and the vibration of the disk were classified into five groups as follows: (1) In the range of 0.6 less-than-or-equal-to s/w less-than-or-equal-to 1.7, the shear layer tore off a square pole and reattached the next square pole. This reattachment excited the Complex Mode III (time phase angle pi/2). The exciting frequency became greater with a decrease of s/w.
(2) In the range of 2.2 less-than-or-equal-to s/w less-than-or-equal-to 3, the shear layer's reattachment and vortex shedding were compounded. A lock-in phenomenon, the same as the one in the range of 3 < s/w less-than-or-equal-to 5, almost was seen. Under the same nordal diameter, the resonant complex-modes changed their order; the first mode was III, the second one was I (time phase angle-pi/2), and the third one was III.
(3) In the range of 3 < s/w less-than-or-equal-to 5, the single voltex was eliminated. The Strouhal number (St) was approximately constant regardless of the s/w and the lock-in phenomenon introduced at the rotation speed where the voltex-shedding frequency equaled the natural frequency of the disk. The resonant complex-mode changed from I to III and shifted to the mode with a succeeding number of nodal numbers.
(4) In the range of 7 less-than-or-equal-to s/w less-than-or-equal-to 23, the multiple vortices were discarded. The number of vortices equaled the integer of s/3w. St decreased linearly with the increase of log (s/w). The resonant became difficult with the increase of s/w. In s/w = 15, the resonant occured only at the smaller number of vortices, and the resonant did not occur when s/w = 23. There were differences between the lock-in phenomena. At the smallest shedding frequency, Mode I resonated at a lower speed than the rotation speed at which the vortex-shedding frequency equaled the natural frequency of the disk, Mode III resonated at a higher speed than it, and no resonant was at it. At another, Mode III was apt to resonate at a lower speed than it.
(5) In s/w = 238.5, vortices generated, and spectra consisted of an assembly of spectrum lines at each rotation speed.

Web of Science

Vibration Characteristics of a Rotating Circular Saw II. Lock-in phenomenon Reviewed

MOKUZAI GAKKAISHI Vol. 35 ( 4 ) page： 306 1989

Vibration Characteristics of a Rotating Circular Saw I. Difference between the amplitude of the forward traveling wave and that of the backward traveling wave Reviewed

MOKUZAI GAKKAISHI Vol. 34 ( 6 ) page： 491 1988

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