| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Noise arising from vibrating parts of various kind of structures could be harmful to Society. and effective expedients for preventing noise have great industrial interest. Wood-based materials are abundantly used as the materials related housing, furniture, packaging and others, and sometimes we have to reduce noise from the vibrating parts of the materials according to the social regulations or from technological standpoints. Adhesives are viscoelastic materials, and therefore each adhesive shows an extremely large damping property within a relatively narrow range of temperature and frequency. Therefore, if we can control the chemical structure and fine structure of the polymer such that it damps vibration in the temperature- and frequency- region corresponding to the actual applicational conditions, and if we apply the polymer as an adhesive, then we can develop a new functional composite material which damps vibration, thus reducing noise. In this study, we have found that the bending vibration of the composites is much more important than the longitudinal vibration, concerning this matter, and a new method of measuring the dynamic mechanical properties by the bending mode. We have found a rule which governs the relationship between the viscoelastic properties of the composites and those of the adhesive which is involved in the composite. It became clear that a symmetrically spaced multilayred structure is preferred in order to get a larger damping. And in order to obtain better adhesives for our purpose, we have investigated on the viscoelasticity of a series of IPNs and polymer blends and on the damping capacity of the composites with woods. Finally, we imposed some mechanical shock on the composites and the noise was analyzed by FFT analyzer. Information which we obtained in this study will serve a good guideline for the development of new wood-based functional composite materials.
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