荔枝树枝力学特性的试验研究

为获取荔枝树枝的力学特性参数,以糯米糍品种荔枝树枝为试验材料,在精密型微控电子式万能试验机上进行了压缩特性和剪切特性试验。测得荔枝树枝顺纹抗压强度平均值为32.77MPa,顺纹抗压弹性模量平均值为1068.02MPa,顺纹压缩能平均值为56.57N.m;树枝横纹抗压比例极限应力平均值为8.02MPa,横纹抗压弹性模量平均值为422.84MPa,横纹压缩能平均值为1.25N.m;树枝剪切强度平均值为9.52MPa,剪切功平均值为17.59N.m。采用统计软件对树枝力学特性参数进行相关性分析,结果表明:顺纹抗压强度和顺纹压缩能之间呈指数函数正相关关系;横纹抗压比例极限应力和横纹压缩能之间呈弱对数函数正相关关系;峰值剪切力、剪切功都与树枝横截面面积呈强线性正相关。试验结果为研制果树修剪机具提供了依据。

Experimental study on mechanical properties of litchi branches

In order to obtain the mechanical characteristic parameters of litchi branches,using "Nuomici"branches as experimental material,compressing test and shear test were conducted in the accurate Micro-controlled electronic universal testing machine.The results showed that average value of crushing strength parallel to the grain was 32.77 MPa,modulus of elasticity parallel to the grain 1068.02 MPa and mean value of the compression energy parallel to the grain 56.57 N.m.Average value of the compressive proportional limit stress perpendicular to grain was 8.02 MPa,modulus of elasticity perpendicular to grain was 422.84 MPa and mean value of the compression energy perpendicular to the grain was 1.25 N.m.Average value of the shear strength was 9.52 MPa and shear power was 17.59 N.m.The relevant changing trends of mechanical characteristic parameters of branches were analyzed with statistical software.The results also showed that there was an exponential function positive correlation between the stress resistance intensity and compression energy parallel to the grain,weak logarithmic function positive correlation between the compressive proportional limit stress and compression energy perpendicular to the grain,and significantly positive linear correlation between maximum shear force as well as shear power and the cross-sectional area.These results provide foundational parameters to develop pruning machine.