Structural mechanism and effect of hole compressibility on mechanical strength of MFLB

Abstract

We have studied the structural mechanism of micron flaky wood fiber light density board (MFLB), of which voids are an important structural characteristic. A new parameter called hole compressibility (?) was added to study the characteristics of MFLB further, in order to produce various levels of hole compressibility. A set of hot pressures was applied, and uniform parts at cross-sections of MFLB were selected to study the effects of hole compressibility on the modulus of elasticity (MOE) and modulus of rupture (MOR) of MFLB by microscopic analyses. The results showed that MFLB (0.3 g/cm³ in density) processed at various hot pressures (from 1.6 to 2.2 MPa) all meet the norms of the Japan Light Particleboard Industrial Standard JISA 5908, where ? ≤ 0 ranging from -0.0487 to -0.068. The critical value of hole compressibility at which the strength began to decrease was also obtained. We compared the void distribution, size and shape at different void contents and hole compressibility and discussed the effects of hole compressibility on MOE and MOR of MFLB as well. To a certain density of raw material and micro-fiber of a certain thickness, the strength of MFLB can be decreased with an increase in hole compressibility. When the hole compressibility of MLFB exceeds a certain critical value, loading at a lower level will decrease MOR and MOE of MFLB considerably.

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