山核桃破壳裂纹产生与扩展试验研究

Research on crack formation and propagation mechanism of walnuts shell breaking

探究山核桃受冲击力破壳裂纹产生与裂纹延展的规律,对突破制约核桃破壳取仁环节装备的瓶颈有较好的指导意义。以皖浙交界天目山区的山核桃为试验材料,采用不同形状的冲头预制裂纹,结合仿真分析研究其对裂纹萌生引导的影响。通过烘烤试验,观察裂纹延展趋势与规律。借助试验结果的启示,设计了山核桃破壳机。破壳部件的敲击锤头与果臼槽采用内附七窝眼的凹槽型结构,使得山核桃在冲击力的作用下,密集分布的棱线能够有效地实现裂纹引导,利于壳仁分离,获得更好的破壳质量。样机通过试验达到了预期效果,其破壳物料为后续加热、振动加工等工序提供便利。

Exploring laws of cracking and propagation of walnut shell under impact force has good guiding significance for breaking through bottleneck of walnut shell breaking and kernel extraction equipment.Using walnuts from Tianmu Mountain area at border of Anhui and Zhejiang provinces as experimental materials,different shapes of punch heads were used to fabricate cracks,and their influence on crack initiation guidance was studied through simulation analysis.Trend and pattern of crack propagation was observed through baking tests.Based on experimental results,a walnut shell breaking machine was designed.Striking hammer head and fruit bowl groove of shell breaking component adopt a groove type structure with seven internal grooves,which enabled walnut to effectively guide cracks under impact force,facilitate separation of shell and kernel,and achieve better shell breaking quality.Prototype has achieved expected effect through testing,and its shell breaking material provided convenience for subsequent heating,vibration processing and other processes.