香玲核桃青皮破裂力学特性试验研究  

Experimental study on cracking mechanical properties of Xiangling walnut green peel

作　　者：陈秀文 李文彬[1,2] 白效鹏 徐道春 CHEN Xiuwen;LI Wenbin;BAI Xiaopeng;XU Daochun(School of Technology,Beijing Forestry University,Beijing 100083,China;Key Laboratory of State Forestry Administration for Forestry Equipment and Automation,Beijing100083,China)

机构地区：[1]北京林业大学工学院,北京100083 [2]林业装备与自动化国家林草局重点实验室,北京100083

出　　处：《中国油脂》2023年第11期135-140,共6页China Oils and Fats

基　　金：国家重点研发计划项目(2019YFD1002401-3)。

摘　　要：为了给青核桃脱皮装备的设计提供理论依据并完善脱皮工艺,对香玲青核桃的几何特征进行测定,并利用微机控制电子万能试验机对其进行不同条件下的单因素力学特性试验。以青皮破裂力和破裂功耗为评价指标,分析了加载方向、加载速率、青核桃外形尺寸、刀片划割处理、阴凉放置处理及青皮含水率对青皮破裂的影响,并拟合了青核桃受压过程中压力随位移的变化曲线。结果表明:香玲青核桃平均球度为0.94,不同部位处青皮厚度不同,青核桃可以简化成非均匀外壳的球体;青皮受压破裂时裂纹只有1条且沿挤压方向延伸出现;青皮破裂受加载方向和外形尺寸的影响,沿纵径方向挤压时青皮更易破裂,青核桃尺寸等级越大,青皮越不易破裂;加载速率对青皮破裂力和破裂功耗的影响不显著;通过烘干降低青皮含水率会影响青皮破裂力和破裂功耗的大小;将青核桃在室内阴凉放置60 h或使用刀片划割后进行加载,青皮更易破裂。因此,为了更好地脱青皮,可以采取对青皮核桃进行分级、刀片划割青皮表面、阴凉放置等措施。Dehulling is an important process in the production of walnuts.In order to provide theoretical basis for the design of green walnut peeling equipment and improve the peeling process.The geometric characteristics of xiangling walnut were determined,and the single factor mechanical property tests were carried out under different conditions by microcomputer controlled electronic universal testing machine.The results showed that the average sphericity of xiangling green fruit is 0.93,and the thickness of green skin at different parts is not uniform.The effects of loading direction,loading rate,size,water content,blade cutting and drying on the cracking of green walnut peel were analyzed by using the cracking force and power consumption as evaluation indexes,and the curve of force changing with displacement during the loading process of green walnut peel was fitted.Experiments show that the green walnut can be simplified as a sphere with non-uniform shell.There is only one crack in the green skin under compression and it appears along the extrusion direction.The skin cracking is affected by the loading direction and overall dimension.The green skin breaking force and breaking power consumption of extrusion along the longitudinal diameter are less than those of extrusion along the lateral diameter.The larger the size grade of green walnut,the more difficult to break green peel.The effect of loading rates on the breaking force and breaking power consumption of green skin is not significant.Reducing the moisture content of green skin by drying can affect the breaking force and breaking power consumption of green skin.If the green walnut is squeezed after placing indoors in the shade for 60 hours or being cut with a blade,the green peel is obviously easier to crack.The results provide a theoretical basis for the development of green walnut peeling equipment and process optimization.

关 键 词：青核桃 脱皮 几何特征 力学特性试验 

分 类 号：TS222.1[轻工技术与工程—粮食、油脂及植物蛋白工程] O342[轻工技术与工程—食品科学与工程]