基于有限元分析的核桃脱壳技术研究

核桃破壳是核桃深加工的第一步，必须首先解决。经实测发现核桃形状不规则、壳仁间隙小。试验证明核桃壳完全破裂所需的变形量大于壳仁间隙，用一般的机械挤压方法破壳必将造成大量的碎仁。该文采用结构静力分析的有限单元法，通过所建核桃的几何模型和破壳的有限元模型，对核桃在几种载荷作用下的应力分布规律进行了分析，找出了核桃壳变形量不大且产生局部裂纹点多、裂纹点易扩展的最佳的施力方式。设计了导向机构。试验表明，核桃导向装置基本实现了使核桃的椭圆长轴与破壳辊轴线平行，使核桃以滚动方式挤压扩展裂纹提高了露仁率。

Technology for breaking walnut shell based on finite element analysis

Breaking walnut shell is the preliminary stage of processing walnut. Irregular shape of walnut shell and small clearance between shell and kernel are found by practical measurement. Experiments proved that the distortion value needed in the safe outburst of walnut shell is bigger than the clearance. Much broken kernel must be produced by generally mechanical extrusion to thresh shell. The finite element method of structure-static analysis is used in this study. The stress distribution and strain of walnut shell under different conditions of force were analyzed by establishing the geometric model and the finite element model for threshing walnut shell. The optimum forcing pattern of producing smaller distortion and more local crackles easily extending was found. A guiding mechanism has been designed. Experimental researches show that the guiding mechanism lets axis of roller for threshing walnut shell and the long axis of walnut ellipse parallel. It is advantageous for extending crackles, walnut shell is entirely cracked, the kernel-obtaining ratio is higher, broken kernel ratio is less, and the quantities of producing kernel in accordance with excellent character are more.