表层接长方式对竹束单板层积材性能的影响

Effect of Surface Veneer Joint on Properties of Bamboo Bundle Laminated Veneer Lumber

采用竹束单板纵向接长的工艺制造连续长度的竹束单板层积材,研究了对接和搭接两种单板接长方式对表层接长的竹束单板层积材力学性能及4循环加速老化耐久性能的影响。结果表明:接头置于受压侧时,板材的静曲强度表现为搭接优于对接;而置于受拉侧时,对接优于搭接;接长方式对板材的水平剪切强度无显著影响。耐久性测试结果表明:经过循环试验后,对照样及接长样的弯曲性能从大到小为对照样、搭接样、对接样,且三者静曲强度非线性曲线拟合结果符合Boltzmann模型,弹性模量符合ExpDec1模型。

Bamboo bundle veneer lengthening technology was explored to produce long-span bamboo bundle laminated veneer lumber （BLVL） , and the effect of veneer-joint forms, such as butt joint and lap joint, on mechanical properties and dura- bility of BLVL after accelerated aging test was investigated. Test results show that the modulus of rupture （MOR） of BLVL with lap joint are better than BLVL with butt joint, when the joint is on the compression side. However, BLVL with butt joint shows higher MOR, when the joint is on the tension side. Besides, the difference on horizontal shear strength of the non-jointed samples, butt joint samples and lap joint samples is not significant. The results of durability test show that after four cycles, non-jointed samples show the highest bending properties, followed by lap joint samples and butt joint samples. The nonlinear curve fitting results of MOR accords with Bohzmann model, and MOE accords with ExpDecl.