Comparison of local variation of modulus of elasticity determined on basis of scanned fiber angles and full strain field measurements

Laser scanning of fiber angles has shown to be a powerful tool to establish bending MOE profiles along boards. This study aims at investigating the accuracy of the MOE variation determined on basis of fiber angles obtained from laser scanning. Material employed was a board of Norway spruce of dimension 50×150×3900 mm. Firstly fiber angles on four surfaces were identified using a WoodEye scanner and based on the fiber angles the MOE profile which was calibrated according to the longitudinal resonance frequency was established. Thereafter the board was subjected to bending and during loading an image correlation system, ARAMIS, was engaged to detect the strain field. Subsequently the strain field was used to obtain the MOE variation. The MOE profiles determined in two different ways were compared and they showed close compliance. However, differences were found as well. The research thus contributes to further improvement of a newly suggested grading method.