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Okazaki, Japan

Takeuchi H.,Chuo Spring Co. | Hoguro M.,Prime Inc | Umezaki T.,Nagoya Institute of Technology
IEEJ Transactions on Electronics, Information and Systems | Year: 2010

KARAOKE is a popular amusement for old and young. Many KARAOKE machines have singing evaluation function. However, it is often said that the scores given by KARAOKE machines do not match human evaluation. In this paper a KARAOKE scoring method strongly correlated with human evaluation is proposed. This paper proposes a way to evaluate songs based on the distance between singing pitch and musical scale, employing a vibrato extraction method based on template matching of spectrum. The results show that correlation coefficients between scores given by the proposed system and human evaluation are -0.76 ∼ -0.89. © 2010 The Institute of Electrical Engineers of Japan.

Hayakawa M.,Japan National Institute of Materials Science | Mizuno H.,Aichi Steel | Suzuki T.,NHK SPRING CO. | Sugimoto A.,Aichi Steel | And 5 more authors.
Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan | Year: 2015

The susceptibility to hydrogen embrittlement for vanadium added spring steel (9254 V) with a tensile strength of 2 GPa class was evaluated by conventional strain rate tensile tests (CSRT) and torsion tests, using smooth specimens respectively. In the CSRT evaluation, the maximum tensile stress decreased with an increment in the diffusible hydrogen content, especially over 5.5 massppm the maximum tensile stress tended to fall off to the lower limit of 1.1 GPa and the fracture appearance changed to fully intergranular. On the other hand, in the torsion tests, the maximum shear stress hardly exhibited any decrease until the hydrogen content reached 6 massppm, where the cracking trace changed from shear plane (transverse direction of the specimen) to a resolved tensile stress plane (45° against the shear plane); fractgraphically, from micro-void coalescence (MVC) to intergranular fracture, and the torsional strength began to decrease. The resistance to hydrogen embrittlement as regards the CSRT properties of 9254 V was superior to that of vanadium-free SAE9254 but with the same tensile strength. Although the superior performance for 9254 V is partially attributable to the reduction of phosphorous and sulfur contents, it should be noted that the addition of vanadium causes refining the prior austenite grains followed by an effective reduction of the intergranular segregation in phosphorus and sulfur, and probably hydrogen trapping at the vanadium carbide interface. However, there was no difference between 9254 V and SAE9254 as regards the torsion properties insusceptible to hydrogen compared with CSRT.

Li W.,Beijing Institute of Technology | Sakai T.,Ritsumeikan University | Wakita M.,Chuo Spring Co. | Mimura S.,Chuo Spring Co.
Materials Science and Engineering A | Year: 2012

The effect of surface finishing and loading condition on competing failure mode of a newly developed spring steel, SUP7-T386, in very high cycle fatigue (VHCF) regime was experimentally studied. As a result, this steel for ground specimen represents the duplex S-N characteristics under rotating bending and the continuously descending S-N characteristics under axial loading, respectively, and all corresponding to surface and interior failure, whereas that for electro-polished specimen represents traditional S-N characteristics with a clear fatigue limit, only corresponding to surface failure. Owing to the combined effect of stress gradient and surface residual compressive stress, as well as the larger size of inhomogeneous microstructure (IM), the interior inclusion-induced failure with fine granular area (FGA) and the interior IM-induced failure without FGA become the predominant failure mode of this steel for ground specimen under rotating bending and under axial loading in VHCF regime, respectively. The threshold stress intensity factor for controlling surface and interior small defect-induced crack propagation of this steel is evaluated to be 2.86MPam 1/2 and 2.04MPam 1/2, respectively, the short crack effect plays a key role in causing the small defect-induced failure of this steel in VHCF regime. Considering the effect of surface residual stress, the surface fatigue limit of this steel can be well evaluated by the size of inclusion or IM. For the evaluation of interior fatigue limit of this steel, it is suitable by the size of IM under axial loading but it is all conservative by the size of inclusion, or IM and or FGA under rotating bending. © 2012 Elsevier B.V.

Miura T.,Ritsumeikan University | Sakakibara T.,Chuo Spring Co. | Mimura S.,Chuo Spring Co. | Kuno T.,Chuo Spring Co. | And 3 more authors.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2015

In order to investigate the interior-induced fatigue crack propagation behavior of spring steel (SUP7), fatigue tests in axial loading were performed for 4 kinds of specimen with different hardness (tempered at 450 °C or 386°C) or residual stress (finished by grinding, electrochemical polishing or shot peening). Harder specimen has indicated longer fatigue life resulting from its mechanical properties of matrix. Ground specimen and shot-peened specimen also provided longer fatigue life than electrochemical-polished specimen, and the fatigue life of shot-peened specimen was almost same as one of ground specimen. After fatigue tests, fracture surfaces were observed using a scanning electron microscope (SEM). In some cases, non-metallic inclusion was not observed at interior fracture origin, but granular microstructure was observed. Profile analysis and crack-path analysis with FRASTA (Fracture surface topography analysis) method were performed to investigate the fatigue fracture mechanism induced by the granular microstructure. As results of these analyses, it was clarified that a facet of the granular microstructure was inclined from 33 to 42 degrees to the fracture surface. It was another finding that small countless cracks emanated discretely inside the granular microstructure during fatigue process. © 2015 The Society of Materials Science, Japan.

Asao M.,Gifu University | Mano H.,Gifu University | Yoshida Y.,Gifu University | Wang Z.,Gifu University | And 2 more authors.
aEngineering Plasticity and Its Applications - Proceedings of the 10th Asia-Pacific Conference, AEPA 2010 | Year: 2011

Shaving is a process to shave off an edge face obtained in shearing. However, in the shaving process, it is generally difficult to obtain the burnished surface over all aspects on the processing surface, because a little fractured surface often remains. Until now, there are a lot of experimental reports for this process, but analytical researches using finite element method etc. are still few. In this study, analytical investigation of an effect of punch tip shape (edge radius and clearance angle of shaving punch) on stress state and strain distribution on processing surface was performed. Furthermore processing conditions of shaving to make burnished surface all over the shaved surface were examined. As the results, it is observed the fracture morphology of shaving is ductile fracture. The shaving load decreases and the burnished surface area increases with increase of tool tip radius.

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