Journal of the Korean Wood Science and Technology
- Volume 26 Issue 1
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- Pages.87-96
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- 1998
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- 1017-0715(pISSN)
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- 2233-7180(eISSN)
Bending Performances of Radiata Pine Veneers and Phenol Resin-Impregnated Sheet Overlaid Plywoods by Nondestructive Evaluation
비파괴평가에 의한 라디에타소나무 단판 및 수지함침시트 표면적층 합판의 휨성능
Abstract
The bending performances were evaluated at the radiata pine plywood through veneer compositions encompassing veneer quality, ply-numbers and overlays of the high density- or medium density-phenol resin impregnated sheets (hereafter abbreviated as resin sheets) on the raw plywood. In addition, a prediction on the bending MOE of veneers and plywoods was carried out by the nondestructive testing with stresswave timer. The summarized results were as follows: I. Bending strength and bending MOE of resin sheets-overlaid plywoods in parallel surface grain direction through 5 and 7ply were increased by 13 to 45% and 17 to 34%, respectively. Resin sheets-overlay occurred an increasing effect of the strength efficiency i.e. strength perpendicular-to-grain direction versus that parallel-to-grain direction, showing the phenomenon that the plywood strength becomes greater at the perpendicular-to-grain direction of 7ply than at that of 5ply. Displacement at bending failure had a greater trend at 7ply than at 5ply, and was decreased by resin sheets-overlay. 2. After the nondestructive bending MOEs were measured for individual veneers, these veneers were rearranged in plywood-manufacture. In these plywoods, including resin sheets-overlay, the actual MOE was predictable with feasibility of
Keywords
- High density- or medium density-phenol resin impregnated sheets;
- stresswave timer;
- resin sheets-overlay;
- strength efficiency;
- nondestructive bending MOEs;
- actual bending MOEs