单板孔洞修补方式对胶合板力学性能的影响OA

To investigate the effects of veneer hole-repair methods on the mechanical properties of plywood,rotary-cut Eucalyptus veneers with circular holes were used as material.Three repair methods,namely veneer patch,calcium hydroxide-based putty and wood-mixed putty,were applied to the holes before plywood manufacture.A non-contact full-field strain measurement system(digital image correlation,DIC)was used to analyze strain transfer during the bonding strength test.The results showed that pronounced local strain concentration occurred around unrepaired holes,disrupting the strain-transfer path.Compared with the control group without holes,the bonding strength,modulus of rupture(MOR),and modulus of elasticity(MOE)of the group with holes unrepaired decreased by 32.92%,18.78%,and 10.65%respectively.Plywood prepared from veneers repaired with calcium hydroxide-based putty(Group CP)and wood-mixed putty(Group WP)exhibited similar strain-evolution patterns during the bonding strength test.These repair materials effectively filled the holes and improved stress transfer.Compared with the unrepaired group,the bonding strength increased by 43.52%and 39.81%,respectively,while the MOR and MOE increased by 18.62%and 10.96%for Group CP and by 14.72%and 7.20%for Group WP,respectively.Although veneer patch repair improved the mechanical properties of plywood to some extent,gaps remained at the hole edges,resulting in insufficient bonding with the veneer substrate and a limited repair effect.Overall,the two putty-based repair methods showed better performance in improving the mechanical properties of plywood,providing a useful reference for the repair of veneer hole defects in plywood production.