荔枝鲜果挤压力学特性  

Extrusion mechanical properties of fresh litchi

作　　者：陈燕[1] 蔡伟亮[1] 邹湘军[1] 向和平[1] 

机构地区：[1]华南农业大学工程学院,南方农业机械与装备关键技术教育部重点实验室,广州510642

出　　处：《农业工程学报》2011年第8期360-364,共5页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家星火计划(2010GA780049);国家自然科学基金资助项目(30900870);广东省自然科学基金资助项目(9251064201000009);华南农业大学校长基金资助项目(2009X004)

摘　　要：为减小荔枝在收获、储运过程中的机械损伤,给荔枝作业装备设计提供依据,试验测定了荔枝鲜果的几何特征,对其果实进行了不同加载条件的挤压试验,并对其果壳进行了拉伸试验。试验得到妃子笑、桂味2种荔枝鲜果在5种加载速率和2种压缩方向下的破裂力分别为76.46～112.90N和38.67～53.83N、破裂相对变形分别为27.93%～32.57%和18.87%～21.27%、弹性模量分别为2.52～4.69×105Pa和4.26～5.93×105Pa。试验表明,荔枝果实的抗挤压能力具有各向异性,其纵向大于横向;妃子笑的各向异性比桂味显著,且抗挤压能力大于桂味;试验范围内加载速率对果实的抗挤压能力影响不显著。荔枝果实可简化为果核呈长椭球体、厚度均匀薄壳球体,利用其简化结构及果壳强度各向异性对其挤压力学特性和裂壳特征的力学原理进行了分析。研究结果可为荔枝收获、加工和运输等提供理论依据。In order to reduce the mechanical damage of litchi in harvesting, storage and transportation, and provide the design basis for operation equipment, the geometric characteristics of fresh litchi were determined in this paper, the extrusion tests were conducted for litchi under different loading conditions. Moreover, tensile tests were carried out for the hulls of fresh litchi. The rupture force of cultivar Feizixiao and Guiwei were 76.46-112.90 N and 38.67-53.83 N under five loading rates and two loading directions, while the relative deformation were 27.93%-32.57% and 18.87%-21.27%, and the elastic modulus were 2.52-4.69×105 Pa and 4.26-5.93×105 Pa. The results of tests showed that the anti-extrusion capacity of litchi fruit was anisotropic and was stronger in the vertical direction than in horizontal direction. The anisotropy of cultivar Feizixiao was more significant than Guiwei, and its anti-extrusion capacity was also greater than Guiwei. The loading rate in this experiment had no significant anti-extrusion capacity. Therefore, litchi fruit can be simplified as uniform thickness shell sphere, and its stone was elongated ellipsoid. According to simplified structure and anisotropy of hulls, the mechanical principle of extrusion properties and cracking characteristics were analyzed. The results can provide a theoretical basis for litchi harvesting, processing and transporting.

关 键 词：挤压 力学特性 果壳 品种 荔枝鲜果 

分 类 号：S183[农业科学—农业基础科学] S667.1