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Details van artikel 26 van 180 gevonden artikelen
| Titel: |
DETERMINATION OF CROSS-GRAIN PROPERTIES OF CLEARWOOD SAMPLES UNDER KILN-DRYING CONDITIONS AT TEMPERATURE UP TO 140° C |
| Auteur: |
Keep, Laura-Beth Keey, Roger B. |
| Verschenen in: |
Drying technology |
| Paginering: | Jaargang 18 (2000) nr. 6 pagina's 1221-1237 |
| Jaar: |
2000-07-01 |
| Inhoud: |
Small specimens of Pinus radiata have been tested to determine the creep strain that occurs during the kiln drying of boards. The samples have been tested over a range of temperatures from 20°C to 140°C. The samples, measuring 150 × 50 × 5 mm, were conditioned at various relative humidities in a pilot-plant kiln, in which the experiments at constant moisture content (MC) in the range of 5-20% MC were undertaken to eliminate mechano-sorptive strains. To determine the creep strain, the samples were brought to their equilibrium moisture content (EMC), then mechanically loaded under tension in the direction perpendicular to the grain. The strain was measured using small linear position sensors (LPS) which detect any elongation or shrinkage in the sample. The instantaneous compliance was measured within 60 sec of the application of the load (stress). The subsequent creep was monitored by the continued logging of strain data from the LPS units. The results of these experiments are consistent with previous studies of Wu and Milota (1995) on Douglas-fir (Pseudotsuga menziesii). An increase in temperature or moisture content causes a rise in the creep straw while the sample is under tension. Values for the instantaneous compliance range from 1.7 × 10-3 to 1.28 × 10-7 MPa-1 at temperatures between 20°C and 140°C and moisture content in the range of 5-20%. The rates of change of the creep strains are in the Order of magnitude 10-7to10-8s-1 for these temperatures and moisture contents. The experimental data have been fitted to the constitutive equations of Wu and Miloia (1996) for Douglas-fir to give material parameters for the instantaneous and Creep strain components for Pinus radiata. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 26 van 180 gevonden artikelen
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