温185核桃压缩力学特性研究

Mechanical compression of Wen 185 walnut shell

为了进一步改进核桃破壳装备的设计与制造,利用万能材料试验机研究核桃压缩破裂的力学过程,分析含水率、加载速度对核桃壳破裂力学参数的影响。沿3个加载方向压缩核桃和空核桃壳,对比分析核桃壳体的破裂过程。在4种不同加载速度(100,200,300,400mm/min)下,对4种含水率(4%,6%,8%,10%)的空核桃壳进行压缩试验,测定核桃壳的破裂力、破裂功、破裂功率和理论弹性模量,并对各力学参数进行显著性分析。结果表明,核桃壳体破裂属韧脆性断裂,空壳核桃壳体在线性区间内的破裂力学参数能较好地反映核桃壳体的压缩力学特性。随含水率和加载速度的变化,核桃壳体的各力学参数呈一定规律变化,且含水率、加载速度对核桃壳线性区间的破裂力、破裂功、理论弹性模量的影响显著,对核桃壳线性区间的破裂功率的影响不显著。

In order to improve the design and manufacture of walnut processing machinery, mechanical properties for compression of whole solid,hollow walnut were analyzed to learn shell breaking process in different loading direction,and reduce mechanical damage of walnut seed in breaking shell process.Hollow walnut which H_2O contents（4%,6%,8% and 10%）were compression tested by microcomputer controlled mechanical through different loading rate（100,200,300 and 400mm/min）.Meanwhile,the force-deformation curves were analyzed and the rupture force,rupture energy,rupture power,and elastic modulus were performed to the basic characteristic quantity in significance.The results showed that：the fracture of walnut shell was ductile-brittle fracture,fracture mechanics parameters of hollow walnut shell in which a linear range relationship hold between compression force and deformation could better reflect compression characteristic changes.Fracture mechanics parameters of hollow walnut shell show some of regularity following the contents of H_2O and loading rate.The contents of H_2O and loading rate has obvious effects on rupture force,rupture energy,elastic modulus of hollow walnut shell.In linear range,rupture power of hollow walnut shell has the tendency of increase,but not significant.