育种小麦籽粒力学特性的有限元分析

Finite element analysis on the mechanical properties of breeding wheat grain

在建立育种小麦籽粒几何模型与有限元计算模型的基础上,运用有限元分析方法对小麦籽粒在压载作用下不同受力部位的应力分布进行了分析,获得了育种小麦籽粒在不同施力位置的压载作用下的力学性质,从而为深入研究育种小麦籽粒的损伤机制、优化脱粒装置提供理论依据。经模型仿真计算和试验结果相比较,得出育种小麦籽粒宏观破裂位置与破裂方向与有限元分析是一致的。在种子腹面施加压缩载荷时,种子的宏观破裂是沿腹沟处的应力裂纹;在种子顶面施加压缩载荷时,种子的宏观破裂是从底面两侧开始,在胚顶部与胚乳共生处相交,而后沿胚中部向下扩展的裂纹;种子的宏观破裂是由内部裂纹引起。

The geometric model and the finite element model with the measured results for breeding wheat grain were established. The stress distribution of breeding wheat grain was analyzed under different pressing locations and different pressing loads by applying the finite element method. The mechanical properties of breeding wheat grain under different pressing locations and different pressing loads were obtained,which could be provided as mechanical parameters for further study on mechanical properties,damage mechanism of breeding wheat grain and optimization of threshing machine. It could be concluded that fracture position and fracture direction of breeding wheat grain were consistent with the finite element analysis results after the comparison was made with the model calculation and the experimental results. When the compression load was applied to the seed abdomen,the macroscopic fracture of the seed presented stress cracking along with the abdominal sulcus,and when the compression load was applied to the top of the seed,the macroscopic fracture of the seed presented crack which began at the both sides of bottom,and then intersected at the top of the embryo and the endosperm symbiosis,finally,extended downward along with the middle of the embryo. Therefore,the macro fracture of the seed was caused by the internal cracks.