Effect of Shape of Cut on Growth-Stress Induced Cracking in Cut Timber.

摘要

Naturally-occurring growth stress patterns in timber are modified by cutting. Stresses in cut timber may cause destructive cracks and splits. This research studies how different shapes of cut affect the stress pattern,and was motivated by the hope that certain shapes of cut might reduce cracking. Three-dimensional finite element analyses show that some oblique cuts reduce cracking near the pith. Finite element and optimization techniques show that for axisymmetric shapes,while cracking may be reduced, a compensating amount of wood is destroyed by making the cut. Experimental work supports the calculations. A listing and user's guide for the analysis/optimization computer program are included.