Abstract:In order to explore the mechanical properties of barley grain in the operation process of harvesting, threshing, storage, transportation and so on, the compression experiment and finite element simulation method (FEM) of barley grain were carried out. At present, the conventional modeling method of irregular shape agricultural material was simplified into regular body to deal with. Because of the difference between barley grain and simulation model in size and surface shape, the actual physical parameters of barley grain were not suitable for the finite element model which was approximately treated, thus existing a few problems, such as more sample consumption and cumbersome measurement. Five wet basis moisture content (7.94%, 11.02%, 14.29%, 16.85% and 20.37%) and three kinds of loading directions (horizontal, width and vertical directions) of barley grain were selected as test materials. Mechanical parameters like and different forms of damage, rupture strength, elastic modulus and compression work of barley grain were measured by universal materials tester. The compression tests results showed that under these conditions the elastic modulus of barley grain was 87.39～167.84MPa, the rupture strength of barley grain was 70.40～157.32N, the yield strength of barley grain was 0.85～2.12MPa, and the maximum strain of barley grain was 0.26%～1.15%. The results showed that the elastic modulus, rupture strength and yield strength of barley grain were descended obviously with the increase of moisture content. The rupture strength in width direction was the maximum and in vertical direction was the minimum under the condition of the same moisture content. The elastic modulus in horizontal direction was bigger than that in vertical direction. Then the threedimensional finite element model of barley grain was built based on 3D laser scanning technology, point clouds of barley grain were acquired by the software Geomagic Studio which were processed by cloud processing and reverse modeling techniques to get high quality point clouds, thus a geometric model highly similar to the real barley grain was obtained. And mechanical analogue simulation was performed based on the geometric model. The compression test results and finite element solutions were compared, and the maximal difference was 7.2%, which showed that the modeling method of barley grain based on 3D laser scanning technology was effective and accurate. The modeling method of barley grain provided a new technology to improve the accuracy of the irregular agricultural material model and reduce the simulation error. Meanwhile, the mechanics parameters and the rules of barley grain could provide reference for its utilization and optimization of related processing machinery.
