Takenaka R and D Institute


Takenaka R and D Institute

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Hidaka T.,Takenaka R and D Institute
39th International Congress on Noise Control Engineering 2010, INTER-NOISE 2010 | Year: 2010

In auditoriums, the acoustical quality differs from one seat to another. This paper examines the spread of acoustical quality in concert halls having three different shapes, shoebox, nonshoebox, and surround. The total acoustical quality is defined as: TAQ = [IACC E3-IACC E3,Avg] 3/2 + [G-G Avg] 3/2 + [EDT-EDT Avg] 3/2. If we write IACC E3 = log(iacc E3) and G = 10log(E), we can write the relative spread as: ΔTAQ= √([Δiacc E3/iacc E3,Avg] 2 + [ΔE/E Avg] 2 + [ΔEDT/EDT Avg] 2). The comparison of the spread in ΔTAQ was measured in 18 concert halls. The results were that the spreads depend significantly on the hall shape, and the largest spread is in the parameter IACC E3. Thus, IACC E3 is judged to be the most significant quantity in the measurement of the spread in acoustical quality from one shape of hall to another.

Hidaka T.,Takenaka R and D Institute | Suzuki K.,Takenaka R and D Institute | Yamada Y.,Takenaka R and D Institute
20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society | Year: 2010

A new miniature dodecahedral loudspeaker appropriate for a 1/10 - 1/20 scale room acoustical model experiment was developed. This sound source consists of a PVDF bimorph film as a transducer, whose vibrating surface shape was mechanically modified so as to improve the acoustical characteristics. The reproducible frequency range is from 15 to 160 kHz with relatively flat responses, and the sound pressure is large enough to allow accurate measurements. Major acoustical characteristics of this source, some new results of the scale model experiment and the proposed signal processing algorithm are reported.

Deguchi Y.,Takenaka R and D Institute | Nagaoka T.,Takenaka R and D Institute | Okazaki T.,Takenaka R and D Institute | Shirahase T.,Takenaka Corporation
AIJ Journal of Technology and Design | Year: 2014

From the viewpoints of environmental issue and forest protection, promotion of the use of wood is demanded. On the other hand, construction of a large-scale fire proof wooden building is possible legally, but the realization is difficult. In such a background, we planned the wooden structure office with wooden interior finishing in Osaka. In this paper, process of exclusion from application of interior finishing restriction by use of results of full-scale interior finishing fire spread experiments.

Kohmura Y.,Takenaka R and D Institute
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2012

In this study the uni-axial compression test using the stress-feedback method was carried out with Inada granite which is a Class II rock. The test was carried out by changing loading direction and water content conditions. A perfect stress-strain curve was measured. The stress-strain curve including the post-failure region was simulated using a spring model. In addition, the effects of anisotropy and water content conditions on the stress strain characterization were examined. © 2012 The Society of Materials Science, Japan.

Nakai M.,Takenaka Corporation | Tanno Y.,Takenaka Corporation | Oka H.,Takenaka R and D Institute | Fujii E.,Takenaka Corporation
AIJ Journal of Technology and Design | Year: 2013

This paper reports the result of case studies for a large scale dome structure with a diameter of approximately 300m. Schematic designs of a total of four domes are conducted to quantitatively evaluate the advantages of using high-strength steel and/or seismic isolation. It is shown that the unit structural weight of the dome with high-strength steel and base isolation can be as small as half of the one without the two.

Kohmura Y.,Takenaka R and D Institute
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014

There are several reports that the static Young's modulus of rocks differs from the dynamic one. In this study, the relation between static Young's modulus and dynamic Young's modulus of rocks is examined. First, static Young's modulus was obtained by the uni-axial compression test, and dynamic Young's modulus was obtained by the ultrasonic transmission method. Secondly, their relationship was examined from the viewpoint of the strain level. In addition, the value of the Poisson's ratio for calculation of dynamic Young's modulus was examined. As a result, it was clarified that the dynamic Young's modulus becomes almost equal to the static one determined from the region of small strain if the Poisson's ratio used to calculate the dynamic Young's modulus is the appropriate value which is measured at the strain level without effect of crack closure. © 2014 The Society of Materials Science, Japan.

Beranek L.L.,10 Longwood Drive | Nishihara N.,Takenaka R and D Institute
Journal of the Acoustical Society of America | Year: 2014

The Eyring/Sabine equations assume that in a large irregular room a sound wave travels in straight lines from one surface to another, that the surfaces have an average sound absorption coefficient αav, and that the mean-free-path between reflections is 4 V/Stot where V is the volume of the room and Stot is the total area of all of its surfaces. No account is taken of diffusivity of the surfaces. The 4 V/Stot relation was originally based on experimental determinations made by Knudsen (Architectural Acoustics, 1932, pp. 132-141). This paper sets out to test the 4 V/Stot relation experimentally for a wide variety of unoccupied concert and chamber music halls with seating capacities from 200 to 5000, using the measured sound strengths Gmid and reverberation times RT 60,mid. Computer simulations of the sound fields for nine of these rooms (of varying shapes) were also made to determine the mean-free-paths by that method. The study shows that 4 V/Stot is an acceptable relation for mean-free-paths in the Sabine/Eyring equations except for halls of unusual shape. Also demonstrated is the proper method for calibrating the dodecahedral sound source used for measuring the sound strength G, i.e., the reverberation chamber method. © 2014 Acoustical Society of America.

Nishihara N.,Takenaka R and D Institute | Hidaka T.,Takenaka R and D Institute
Journal of the Acoustical Society of America | Year: 2012

Objective acoustical parameters for halls are often measured in 1-octave bands with mid-frequencies from 125 to 4000 Hz. In reality, the frequency range of musical instruments is much wider than that, and the fundamentals of the lower notes of bass instruments are contained in 31.5 or 63 Hz bands. Overtones of fundamentals in these bands fall in 125 Hz band. This report presents subjective experiments designed to determine to what extent the overtones in 125 Hz band and higher bands influence the loudness sensation of the components in 63 Hz band. In the experiments, the 125 Hz and higher components of the musical tone are used to act as a masker against the lower component used as a maskee. The threshold of the difference between G(125 Hz) and G(lower band) that just enables one to hear the fundamental tones in the lower band is determined. Masked loudness of 63 Hz sinusoidal tone caused by partial masking noise with higher frequencies was determined based on a similar procedure to the masked loudness-matching function. The result indicates that the difference in loudness of low tone will not be noticeable even if G changed by ±2.5 to ±3 dB, at least when there are other accompanying instruments. © 2012 Acoustical Society of America.

Higashino M.,Takenaka R and D Institute | Ohtake K.,Takenaka R and D Institute | Hamaguchi H.,Takenaka R and D Institute | Wada A.,Tokyo Institute of Technology
Journal of Structural and Construction Engineering | Year: 2010

The number of seismically isolated buildings has been increasing after Hanshin-Awaji earthquake in Japan. One of the structural designs of recent seismic isolation is specialized by isolation of super high rise buildings. Many of these buildings employ sliding isolation bearings to further elongate its natural period of isolation layer compared to that of superstructure. Seismic isolation enhances the safety of building during earthquake. But the fatigue caused by deformation during strong wind must be checked, since building in Japan suffers from strong typhoons during its lifetime, especially if they are high rise buildings. The authors have conducted fatigue tests of sliding bearings especially (or its rubber pad. Also, the authors have evaluated the wind levels and the duration for each wind level which the building experiences during its lifetime. By conducting wind response analyses, considering the fatigue test results and the wind excitations which the building experience during its lifetime, the evaluation method of fatigue is proposed and expected fatigue level using proposed method is presented.

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