Nondestructive evaluation of modulus of elasticity of yellow poplar LVL

摘要

Nondestructive testing (NDT) methods, stress-wave propagation and transverse vibration, were used to evaluate the modulus of elasticity (MOE) of laminated veneer lumber (LVL) fabricated with rotary-peeled yellow poplar veneers and phenol-formaldehyde resin. Three groups of LVL specimens, 25 in each group, randmly selected from a very large sample population, were prepared for this study. Group I specimens had scarfed veneer-joints, group II had crushed-lap joints and group III had no veneer joints and served as controls. All specimens were preconditioned and equilibrated under environmental conditions of 65percent RH and 23.9 deg C (75 deg F). Results showed that MOE of LVL predicted by NDT was influenced by the veneer-joint designs and that a difference existed between the NDT methods used. Furthermore, a comparison between MOEs evaluated by NDT methods and destuctive static bending tests, was presented.