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| Titel: |
Measuring Temperature Dependence of Secondary Forming Behavior of Cellular Polystyrene Sheets |
| Auteur: |
Ito, Katsuhiko Yatabe, Osamu Tsutsui, Makoto Fujisaki, Hiromu |
| Verschenen in: |
International journal of polymeric materials |
| Paginering: | Jaargang 10 (1983) nr. 1 pagina's 39-52 |
| Jaar: |
1983-03-01 |
| Inhoud: |
Foamed polystyrene extrusion sheet is often post-formed at reasonably warm temperatures for various final applications. Modified Erichsen testing apparatus with heating chamber is used for evaluating temperature dependence of post-forming ability of foamed polystyrene sheet. Circular sheets (90 mm diameter) of thickness (1.5 mm-2.4 mm) are used as test specimen in this experiment. The fracture of sheet specimen at hemi-spherical punch corner can be observed through upper glass plate during the punch penetration travel. Profile of holding die, thickness of test specimen and clamping conditions (neat fit, press fit and clearance fit) of sheet specimen between dies are varied in this experiment and their effects on the fracture penetration depth are investigated at various working temperatures (30-100°C) with the interval of 10°C. In general, Erichsen fracture values increase greatly with working temperatures. While the effect of clamping conditions are not clear, Erichsen fracture values increase with the increase of inner diameter of holding die and thickness of foamed blank. Erichsen recovery is measured as strain retentivity for complicated post-forming of foamed polystyrene. The test specimen was processed initially to fixed Erichsen depth (9 mm) at the temperatures of 70°C and 80°C, and then is free-annealed for 3 hours at the temperatures higher than the initially processed temperatures in order to cause strain recovery of the test specimen. The residual Erichsen depth after the annealing is measured and the Erichsen recovery percentage are calculated. As expected, the Erichsen recovery increases greatly with annealing temperature rise and is almost perfect at the annealing temperature of 100°C. Finally, it is suggested that sheet profile of the penetration of hemi-spherical punch into a circular blank fixed rigidly with surrounding boundary, is analyzed theoretically on the basis of theory of rubber elasticity, assuming that the material is incompressive, isotropic and homogeneous, with fixed boundary condition of membrane, and further the central part of the circular blank is relaxed and set immediately after the contact with punch head. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 3 van 7 gevonden artikelen
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