Analysis of the microstructure and mechanical properties of laminated veneer lumber

Abstract

In this paper, four different nondestructive testing (NDT) methods and static bending tests were done on poplar (Populus ussuriensis Kom.) and birch (Betula platyphylla Suk.) Laminated Veneer Lumber (LVL). The effects of compression ratio on the modulus of elasticity (MOE) and modulus of rupture (MOR) of LVL with vertical load and parallel load were investigated. There were four compression ratios: 8.1%, 18.3%, 26.5%, and 33.1%. The microscopic structure of LVL was analyzed with a scanning electron microscope (SEM). Results showed a strong correlation between each dynamic Young's modulus and the static MOR of LVL; the MOE and MOR of LVL changed with the increase of compression ratio. MOE and MOR were greatly increased when the compression ratio increased from 18.3% to 26.5%, and the microstructure of LVL changed greatly between different compression ratios by birch and poplar species.