改性速生杨木抗压性能试验研究

Experimental study on mechanical behavior of modified fast-growing poplar

速生杨木在中国种植范围广,但由于力学性能差、变形大等缺点,其应用受到很大限制,迫切需要对速生杨木进行改性处理。主要考虑不同板材厚度(5、10、15、20mm)和不同纹理(径向、弦向)两个因素对改性速生杨木进行力学性能试验研究。试验表明:随着板材厚度的减小,试件破坏由单个斜截面破坏至连续斜截面破坏,再到水平压皱破坏,最后出现双曲破坏和单板弯曲破坏。不同板材厚度改性试件抗压试验中,与对比试件相比,改性试件的力学性能有较大提高,且随着板材厚度的减小,试件的抗压强度、峰值压应变、弹性模量等均显著增大。不同纹理组合改性试件抗压试验中,弦向与弦向纹理组合试件力学性能最优,其次为径向与径向纹理组合试件,最低为弦向与径向纹理组合试件。同时,在顺纹加顺纹的纹理组合方式下,与对比试件相比改性试件的抗压强度、峰值压应变、弹性模量等均有提高显著;在顺纹加横纹的纹理组合方式下,改性试件的抗压强度和弹性模量反而有所降低。

Fast-growing poplar has been widely planted in China. For the poor mechanical properties and large deformation of the timber, its application is greatly restricted. Modified fast growing poplar specimens with different plate thicknesses of 5, 10, 15, 20 mm, radial direction and chord direction), under different parameters were tested in this paper. The tests indicate that the failure gradually began by the single oblique section,then the horizontal crinkling failure occurs, finally to the double curvature failure and the single plate bending failure with gradual decrease of the plate thickness. In the compressive test of the modified specimens with different thicknesses, the mechanical properties of the modified specimens are improved greatly compared with the control specimens, the compressive strength, the peak compressive strain and the elastic modulus of the specimens increase significantly with decrease of the plate thickness. In the compression test of different texture combination modified specimens, the mechanical properties of chord and chord texture combination specimens are the best, followed by radial and radial texture combination specimens, and the lowest is chord and radial texture combination specimens. At the same time, the compressive strength, peak compressive strain and modulus of elasticity are significantly higher than those of the control specimens, and the compressive strength and modulus of elasticity of the modified specimens are lower than those of the control specimens.