Abstract: In order to optimize the design of macadamia nut opening machine, discrete element simulation analysis was carried out on the conveying process of macadamia nut in the machine. The intrinsic parameters of macadamia nut were extracted and an experimental platform was built to verify the reliability of discrete element parameter calibration. Through uniaxial compression experiments, the Poisson's ratio of magnolia grandiflora was 0.29, the elastic modulus was 50.1 MPa, and the density was 1.019 g/cm3. Central Composite Design was adopted to obtain the optimal combination scheme of stacking angle and the optimal calculation scheme. The collision recovery coefficient between macadamia nuts was 0.502, the rolling friction coefficient between macadamias is 0.03, and the static friction coefficient between macadamia nuts was 0.318. The collision recovery coefficient of macadamia‑duralumin alloy plate was 0.759, the static friction coefficient of macadamia‑duralumin alloy plate was 0.502, the rolling friction coefficient of macadamia nut‑duralumin plate was 0.001 77. The calibration parameters were verified by cylinder lifting and conveying experiments. The experimental results showed that the error between the simulated and measured macadamia nut pile angle after calibration was less than 1%. The test showed that the particle distribution under the simulation conditions was basically the same as that of the test macadamia nut pile angle, and the calibration results were reliable, which could provide a theoretical basis for the design optimization of macadamia nut related equipment.

Key words: macadamia nut, intrinsic parameter, discrete element simulation, parameter calibration, transport test

摘要： 为优化夏威夷果开口机的设计，对夏威夷果在机器中的输送过程进行离散元仿真分析，提取夏威夷果本征参数并搭建试验台验证离散元参数标定的可靠性。通过单轴压缩试验得到夏威夷果的泊松比为0.29，弹性模量为 50.1 MPa，密度为1.019 g/cm3。采用Central Composite Design得出堆积角最佳组合方案和最佳计算方案，标定出夏威夷果间的碰撞恢复系数为0.502，夏威夷果间的滚动摩擦因数为0.03，夏威夷果间的静摩擦因数为0.318，夏威夷果—硬铝合金板的碰撞恢复系数为0.759，夏威夷果—硬铝合金板的静摩擦因数为0.502，夏威夷果—硬铝合金板的滚动摩擦因数为0.001 77。对标定后的参数进行圆筒提升与输送试验验证，结果表明,标定后的夏威夷果仿真堆积角与实测堆积角误差小于1%，仿真条件下颗粒分布情况与实际试验的夏威夷果分布情况基本相同，标定结果可靠，可为夏威夷果相关机具的设计优化提供理论依据。

关键词: 夏威夷果, 本征参数, 离散元仿真, 参数标定, 输送试验