Studies of Flexural Creep Behavior in Particleboard Under Changing Humidity Conditions
Keywords:Particleboard, oriented particleboard, plywood, moisture content, creep, cyclic testing, relative humidity, mechanical properties, stress level
AbstractThe effect of changing relative humidity, to cause simple adsorption or cyclic adsorption-desorption, on the creep behavior of particleboard, oriented particleboard, and plywood was studied. For the particular boards studied, creep response was sensitive to the highest humidity to which the boards were subjected. Behavior of both urea and phenolic resin-bonded particleboards was similar. When stressed below approximately 20% of maximum static bending strength, flexural creep was linear with stress level. An increased rate of adsorption had a smaller overall effect than the greatest humidity level to which the board was subjected. A shavings/residue-type particleboard demonstrated accelerated creep behavior above about 75% RII. Although plywood and oriented particleboard had increased creep at the higher humidity levels, there did not appear to be as definite a point where creep rate accelerated. Flexural creep behavior under a single concentrated load was qualitatively similar to that under simple flexural stress.
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