Authors

Abstract

In order to find the variations of mechanical properties of millet stalk during dynamic cutting, a three-dimensional model of cutting parts and a double-layer flexible model of millet stalk were established in this study. The mechanical cutting properties of millet stalk at different cutting speeds and blade oblique angles were investigated based on ANSYS/LS-DYNA, while the verification tests were carried out based on the self-made cutting test bench. Simulation results showed that the maximum Von Mises stress was concentrated on the contact point of the stalk and the moving blade. The maximum Von Mises stress of stalk during extrusion, cutting, and after cutting were 60.03 MPa, 60.72 MPa, and 39.87 MPa, respectively, and the cutting energy of stalk epidermal tissue was greater than that of inner tissue. The cutting stress and the unit area cutting energy decreased first and changed steadily as cutting speed was increased when the cutting speed was 0.5-1.5 m/s. When the blade oblique angle was 0°-48°, the cutting stress decreased as the blade oblique angle was increased, while the unit area cutting energy decreased first and then increased. Verification tests showed that the cutting speed and the blade oblique angle had significant effects on the cutting mechanical properties (P < 0.05), which was consistent with the simulation test results. Research results can be used to optimize the cutting parameters of millet stalk

Abstract in Chinese

为探究谷子茎秆动态切割过程中的力学特性参数变化规律，本文建立了切割部件三维模型与谷子茎秆双层柔性模型，以切割速度与刀片斜角为影响因素，基于ANSYS/LS-DYNA对谷子茎秆进行动态切割力学仿真，并采用自制切割试验台进行验证试验。仿真结果表明：茎秆切割过程分为挤压与切割茎秆两个阶段，且最大Von mises 应力集中于茎秆与动刀片接触部位，挤压过程、切割过程与切割完成后茎秆最大Von mises 应力分别为60.03 MPa、60.72 Mpa和39.87 MPa, 且茎秆表皮层较内层切割功耗大。当切割速度为0.5—1.5 m/s时，切割应力、单位面积切割功耗随切割速度的增大而减小后呈现平稳变化的趋势；当刀片斜角度0°—48°时，切割应力随刀片斜角的增大而减小，而单位面积切割功耗随刀片斜角的增大先减小后增大。验证试验表明：切割速度与刀片斜角均对其切割应力、单位面积切割功耗影响显著（P<0.05），与仿真试验结果吻合。研究结果可为谷子茎秆切割参数优化提供借鉴。