Seikei-Kakou
Online ISSN : 1883-7417
Print ISSN : 0915-4027
ISSN-L : 0915-4027
Volume 6, Issue 4
Displaying 1-3 of 3 articles from this issue
  • Hiroshi ITO, Yasuhiro TSUTSUMI, Keiji MINAGAWA, Kazumi TADA, Kiyohito ...
    1994 Volume 6 Issue 4 Pages 265-270
    Published: April 20, 1994
    Released on J-STAGE: November 18, 2009
    JOURNAL FREE ACCESS
    Injection molding processes of crystalline polymers were simulated with a crystallization kinetics program. Crystallinity and spherulite size were evaluated at various points of a product model, by using pressure, shear stress, and temperature data obtained with a computer aided engineering (CAE) program. It was found that crystallinity and spherulite size have maximum values at the same depth between the surface and center layers, suggesting that they are closely related to each other. It was also confirmed that the variation of crystallinity with depth qualitatively agrees with experimental data in the literature.
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  • Masahiko HIRAO, Masahiro FUJII, Shunichi KAWANO, Hiroshi FUJINO
    1994 Volume 6 Issue 4 Pages 271-277
    Published: April 20, 1994
    Released on J-STAGE: November 18, 2009
    JOURNAL FREE ACCESS
    As a result of the increase in demand for an impact resistance of polymer moldings, many attempts have been made to characterize their behaviour using CAE method. However, the use of a constant Young's modulus or yield stress in CAE method introduces significant errors under the high strain-rates caused by impact or drop situation.
    In this study, we investigate the effect of strain-rate and temperature on the mechanical properties of ABS resin. A standard tensile testing machine with crosshead speeds from 0.2 to 500mm/min was used to observe the tensile and compressive behaviour. A Hopkinson test apparatus was used to observe the compressive behaviour under high strain-rate conditions.
    Additionally, the effect of varying ambient temperature (from 0 to 60°C) on mechanical properties was investigated.
    From these experiments following results are obtained.
    (1) Even under low strain-rate region the effect of strain-rate on yield-stress is remarkable. And the yield stress can be expressed as a exponential function of strain-rate.
    (2) It can be expected that the mechanism of deformation between tensile and compression were different. Especially the stress was increased after yielding at tensile test, but such phenomenon was not observed at compression test.
    (3) The stress-strain curves were similar to that of low strain rate under the impact compression. The relationship between the yield stress and strain can be also expressed by a exponential function as stated (1) among the wide range of strain-rate.
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  • Sadao SATO, Akira ITOGA, Kimitaka ITO, Yasushi OYANAGI
    1994 Volume 6 Issue 4 Pages 278-285
    Published: April 20, 1994
    Released on J-STAGE: November 18, 2009
    JOURNAL FREE ACCESS
    A p-v-T device for determining the specific volume of solid and liquid polymer alloys as a function of pressure (up to 200MPa) and temperature (30-350°C) has been constructed. It is a plunger type which consists of a plunger, cylinder, heater and laser displacement meter. The measurement accuracy of the device was within ±2-3%. The p-v-T properties were determined by the isothermal testing method. We have discussed the effects of the mixing ratio on p-v-T properties of polymer alloys and the empirical equation of state. The empirical equation of state for amorphous polymers such as PPO, PS and its alloys is presented as follows:
    v(p, T)=vo(0, To)+(3i=0AiTi+p1i=0BiTi+p21i=0CiTi)
    Here, v is specific volumes as a function of pressure and temperature, vo is specific volume at atomospheric pressure (p=0) and room temperature (To). The Ai (i=0-3), Bi and Ci (i=0-1) are coefficients of the p-v-T characteristic each polymers. The values of these coefficients were determined by a least-squares fitting method. The specific volumes of solid and liquid amorphous polymers determined by the em. pirical eq. agree with the measured values to within 1.07% to 1.80% except for PPO. The volume strain Kv of the solid and molten polymer alloys changed irregularly depending on the mixing ratio. It is minimum when the mixing ratio is PPO/PS=20/80 weight percent.
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