Rate- and duration-of-load behavior of lab-made structural flakeboards

: Tests of structural use panels under different loading conditions provide basic information for establishing design stresses. This paper reports the effects of loading rate in tension and bending and of duration of load in tension on the properties of four lab-made structural flakeboards, (two of which had aligned flakes). The objective was to determine if these panels-made from larger, engineered flakes-behaved the same as commercial particleboards-made primarily from planer shavings and sawdust-that were evaluated in an earlier study. For specimens loaded to failure at different rates of deformation, strength decreased 12 pct in tension and 8 pct in bending with each tenfold increase in time to maximum load. Modulus of elasticity decreased 4 to 5 pct. For specimens loaded in tension at constant stress levels from 50 to 90 pct of static strength, time to failure increased tenfold with each 8 pct decrease in stress. These results for the lab-made structural flakeboards are essentially the same as those reported earlier for commercial particleboards. Keywords: Flakeboard, stress-rupture, particleboard, rate of loading, duration of load, tension, bending. (Author)