典型品种花生米静压力学特性及有限元分析

Static Mechanical Property and Finite Element Analysis of Typical of Peanut Varieties

为深入研究花生米的力学特性,从机理上解决花生脱壳机械加工过程中的花生米破损伤问题,选取辽宁省主栽花生品种大白沙、黑花生、两粒红和小白沙为研究对象,使用万能物料试验机进行花生米静压力学特性试验,分析不同含水率(4%、14%、21%和32%)、不同放置方式(正放、侧放和立放)下各品种花生米的破损形式、破损力、变形量及压缩功的变化情况,并使用有限元法,对花生米组织内部的应力和应变情况进行建模分析。结果表明:花生米的损伤形式与含水率有关,含水率为4%时,不同放置方式下花生米内部损伤均大于50%;含水率为32%时,不同放置方式下花生米内部损伤均小于20%;在5%的显著性水平下,花生米的含水率和放置方式对破损力有显著性影响,外力加载速度对破损力无显著性影响;花生米立放时的破损力普遍小于正放和侧放;花生米的破损力随含水率的增加而增加,二者近似呈线性关系;花生米破损过程中的压缩功随含水率的增加而增加;正面加载时,花生米水平方向横截面积越大,应力和位移越小;腹面加载时,子叶结合面处应力和位移最大;顶部加载时,中间部位应力最大,顶部位移最大。试验结果与花生米实际损伤情况相符,研究结论可为花生的运输、加工等环节技术参数的设计优化提供理论基础。

In order to solve the injury problems of peanut grains during the mechanical shelling process based on mechanical properties of peanut, Dabasha, Black Peanut, Lianglihong, Xiaobaisha the main planting varieties in Liaoning province were selected as the test materials, the static compression tests were carried out by universal material testing machines. The damage forms, breakage force, deformation and the compression work under different moisture contents（4%, 14%, 21% and 32%） and placement forms（right placing, side placing and standing placing） were analyzed using a finite element method. The stress and strain conditions of peanuts were modeled and analyzed. The damage forms of peanut related to the moisture contents. When the moisture content was 4%, the breakage forces were less than 50% of all placement forms; when the moisture content was 32%,the breakage forces were less than 20% of all placement forms; the moisture contents and placement forms had significantly influence on the breakage force, but the external force loading speeds had little influence on the breakage force under 5%significant level. The breakage force of standing placing was generally less than that of right placing and side placing; the breakage force increased as moisture content increasing. The greater peanuts in the process of peanut kernel breakage increased as moisture content increasing. The greater the peanuts horizontal cross-sectional area, the smaller the stress and displacement of the front loading; the stress and displacement were the greatest at cotyledon surface of the negative loading; the middle stress was the greatest and top displacement was the greatest in the top loading. This work could provide theoretical basis for transportation and processing for process parameter optimization design in peanuts.