黑沙蒿直根的材料力学特性研究

Study on the Material Mechanical Properties of Straight Roots of Artemisia ordosica

以鄂尔多斯采煤塌陷区植物的优势种之一黑沙蒿为研究对象,采用伺服式强力机研究其直根的材料力学特性。结果表明:在1~5mm径级范围内抗拉力、抗折力与根径均呈幂函数正相关,抗拉强度、抗折强度与根径呈幂函数负相关。在拉力和折力分别作用下,直根均表现出弹塑性变形特征,抗拉极限弹性力大于抗折极限弹性力,轴向弹性变形小于径向弹性变形。直根承受径向折力的σ~ε(应力—应变)曲线基本为下凹型,承受轴向拉力时的σ~ε曲线基本为上凸型,对于两种受力形式,极限强度均随根径的增大而减小,极限应变与根径无相关性。1~5mm根径直根的平均抗拉强度(8.32±1.67)MPa大于平均抗折强度(5.39±0.85)MPa,表明黑沙蒿直根抵抗轴向拉力的能力优于抵抗径向折力。

In this paper,we adopt servo-type strong machine to research the material mechanical properties of straight roots of Artemisia ordosica which is one of the dominant species in the coal mining subsidence area of Ordos.Results showed that the anti-tension force and the anti-fracture force of straight roots of Artemisia ordosica were positively correlated with the diameter of roots with a power function and both of the anti-fracture strength and the anti-fracture strength were negatively correlated with the root diameter with a power function in the 1-5 mm diameter range.Under the action of tension force and fracture force,the straight roots＇ ultimate anti-tension elastic force was greater than the ultimate anti-fracture elastic force and its axial elastic deformation was smaller than the radial elastic deformation,it showed the characteristics of elasto-plastic deformation.Theσ（stress）—ε（strain）curve under fracture force and tension force of the straight roots were concave and convex respectively,the ultimate strength decreased with the increase of root diameter,and the ultimate strain had no correlation with root diameter under these two kinds of force.The average anti-tension strength of the straight roots was greater than the average anti-fracture strength（（8.32±1.67）MPa〉（5.39±0.85）MPa）in the 1-5 mm diameter range,it showed that the ability of the straight roots to resist axial tension force was better than the ability to resist radial fracture force.