定向刨花板抗弯性能、形变及剖面密度梯度的相关性  

The relationship of bending strength,deformation and VDP of OSB

作　　者：李东虎 李万兆 梅长彤 LI Donghu;LI Wanzhao;MEI Changtong(College of Materials Science and Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学材料科学与工程学院,南京210037

出　　处：《林业工程学报》2023年第3期52-57,共6页Journal of Forestry Engineering

基　　金：国家重点研发计划(2021YFD2200602);江西省林业局科技创新专项(202135)。

摘　　要：定向刨花板(OSB)力学性能优异,但变异性较大,探究OSB抗弯性能变异性大的原因可为改善其力学性能提供理论依据。采用三点弯曲法检测OSB沿长度方向的弹性模量(MOE)和静曲强度(MOR),使用数字散斑应变分析技术(DIC)同步记录试件面内应变分布,结合剖面密度梯度(VDP)探索了其对OSB抗弯性能及形变的影响。结果表明,OSB的MOR与试件整体形变呈线性正相关,MOE与试件整体形变相关性不强。最大载荷条件下,对称的表面结构可有效避免局部应变集中导致的OSB力学失效,这有助于提高OSB的MOR;40%最大载荷条件下,OSB趋于整体弯曲变形,且组成单元的相对位置固定可提高其MOE,内部孔隙压缩会降低其MOE。最大载荷条件下,弯曲应变分布与VDP相似,会提高试件MOR;40%最大载荷条件下,弯曲应变分布与VDP的相似性和MOE不显著相关。增加结构的对称性、弯曲应变分布和VDP的相似性,能够提高OSB的MOR;增加整体弯曲变形和降低内部孔隙压缩率,能够提高OSB的MOE。Oriented strand board(OSB)is an environmentally and economically friendly material based on the use of renewable resources,mainly fresh wood and from small and large diameter logs.OSB is composed of cross-oriented layers consisting of thin and rectangular wooden flakes or strands that are compressed and bonded together with synthetic resin adhesives.OSB is an alternative to structural plywood for a wide range of lightweight timber frame construction with high variability in flexural properties.This study compares the causes of differences in the flexural performance of OSB.Two different thickness OSB panels were provided from the same company.These panels aim to be used as load bearing materials in dry conditions.The modulus of elasticity(MOE)and static flexural strength(MOR)along the length of the product are measured using the three-point bending method,the in-plane strain distribution of the specimen is recorded simultaneously using digital image correlation(DIC),and the factors influencing the flexural performance of OSB are profiled in conjunction with vertical density profile(VDP).The results show that the MOR of OSB is linearly and positively correlated with deformation,and the MOE is not significantly related to deformation.Under the maximum load condition,the increased symmetry of surface structure and strength of OSB,as well as the effective absorption of external energy and structural changes in the core layer increase the MOR.This is because the strain concentration caused by surface strain defects can lead to premature mechanical failure of OSB,and the core layer needs to absorb energy to mitigate surface damage in the later stages of loading.At 40%of the maximum load condition,the MOE of OSB The MOE of the OSB was affected by the overall degree of bending and the internal pore compression.Increasing the overall degree of bending increased the MOE of the specimen and increasing the internal pore compression decreased the MOE of the specimen.Under the maximum load condition,the bending strain distribu

关 键 词：定向刨花板 剖面密度梯度 静曲强度 弹性模量 应变分布 

分 类 号：TS653.5[轻工技术与工程]