Mechanical properties of MDF [medium density fiberboard] having differed density profile and its nondestructive assessment with ultrasonic wave
2006
Ohashi, K.(Iwate-ken. Forest Experiment Station, Takizawa (Japan)) | Castellianos, J.R.S. | Hatano, Y. | Shibusawa, T.
Several MDF having differed density profile were manufactured by changing closing speed of hot press and MOR and MOE in bending, internal bond and thickness swelling were examined. Moreover, their ultrasonic velocity along the longitudinal direction and the thickness direction were measured to investigate relationship between static MOE and dynamic MOE. Results were obtained as follows: (1) MOR, MOE, and IB became higher and TS became lower as the peak density layer was formed nearer the surface. (2) As static MOE and the product of peak density and effective moment of inertia of area ratio showed a positive straight line relation, it was thought that the peak density and the position of the peak density layer determine MOE. (3) Static MOE agreed well with dynamic MOE computed using the ultrasonic velocity along the longitudinal direction measured on the same surface. From these findings, it is concluded that the ultrasonic velocity along the longitudinal direction measured on the same surface is applicable to estimate MOE of MDF having differed density profile nondestructively.
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