李占福^1a，1b ，戴珂我^1a ，高紫圣² ，黄清芳²

1. 福建理工大学 a. 机械与汽车工程学院， b. 福建省智能加工技术与装备重点实验室， 福建 福州 350118；2. 福建省金龙稀土股份有限公司， 福建 龙岩 366300

引用格式：

李占福，戴珂我，高紫圣，等.基于JKR模型的钕铁硼合金颗粒流动性的离散元参数标定［J］.中国粉体技术，2026，32（6）：1-11.

LI Zhanfu，DAI Kewo，GAO Zisheng，et al.Parameter calibration of discrete element method for NdFeB alloy particle flowability based on JKR model［J］.China Powder Science and Technology，2026，32（6）：1−11.

DOI：10.13732/j.issn.1008-5548.2026.06.010

收稿日期：2026-01-16，修回日期：2026-04-11，上线日期：2026-05-11。

基金项目： 国家重点研发项目，编号：2022YFB3504602；福建省科技厅-高校产学合作项目，编号：2024H6015；福建省教育厅、省工信厅技术创新重点攻关及产业化项目，编号：2023XQ002；福建省财政厅项目，编号：GY-Z24187。

第一作者： 李占福（1987—），男，教授，博士，硕士生导师，研究方向为多物理场耦合数值模拟分析。E-mail：jafu. lee@163. com。

通信作者： 黄清芳（1983—），男，高级工程师，博士，硕士生导师，福建省高层次b类人才，研究方向为磁石材料。E-mail：sduhqf@163. com。

摘要：【目的】解决钕铁硼合金粉末活性高、难以在空气中测量流动参数的问题，在惰性气体氛围下获取流动性指标并完成离散元（discrete element method，DEM）参数标定，为后续分析提供可靠参数。【方法】物理实验测定粉末物性，确定仿真参数范围；在惰性气体氛围下实测休止角并建立离散元模型，基于钕铁硼粉末易黏附的特性选用Johnson-Kendall-Roberts（JKR）黏附接触模型；采用响应面法标定：Plackett-Burman筛选显著参数，最陡爬坡确定优值区间，Box-Behnken

构建二阶回归模型，以实测休止角为目标求解最优参数组。【结果】惰性气体氛围下实测休止角为52. 45°，对流动性影响显著的参数为颗粒间静摩擦系数、颗粒间滚动摩擦系数及钕铁硼合金与不锈钢间静摩擦系数，最优参数组分别为0. 428、0. 13、0. 258，模拟结果与实测值相对误差为0. 66%。【结论】惰性气体条件下可实现钕铁硼合金粉体流动参数的可靠测量，并可通过响应面法完成DEM关键接触参数的有效标定，最优参数组能高精度复现实测休止角。

关键词： 钕铁硼合金； 粉末冶金； 离散元； 响应面法； 参数标定

Abstract

Objective　Reliable discrete element method（DEM）analysis of neodymium iron boron（NdFeB）alloy powders requires flow-property measurements that reflect their real and highly reactive state. However，because exposure to air is restricted for NdFeB 10 alloy powder，flowability is often measured after oxidation，which limits the reliability of DEM parameter calibration.In this study，the flowability of NdFeB alloy powder is measured under an inert gas atmosphere for the first time，and a DEM calibration method is established to obtain accurate and transferable parameters for subsequent numerical analyses.

Methods　Flow-property characterization was carried out under an inert gas atmosphere to avoid oxidation，ignition，and property distortion during handling.Key physical properties required for DEM modeling，including density and elastic-related parameters，were determined through experiments，and particle morphology was analyzed to support geometric representation in simulations. To balance computational efficiency and shape fidelity，a coarse-grained particle model with an equivalent size of 8 μm was adopted.Three representative particle morphologies—triangular platelet，rectangular platelet，and rhombohedral particle—were introduced in equal proportions.To captureshort-range adhesion induced by van der Waals attraction and the interlocking effects among micron-sized particles，the Hertz-Mindlin with Johnson–Kendall–Roberts（JKR）contact model was used.DEM simulations of angle-of-repose measurementswere established to reproduce powder discharge，pile formation，and contour extraction. Parameter calibration was then conducted using response surface methodology. A Plackett–Burman design was first used to identify significant contact parameters from the candidate variables，including restitution coefficients， static and rolling friction coefficients，and surface energy.Steepest ascent tests were subsequently employed to locate the optimal parameter interval，after which a Box-Behnken design was used to establish a second-order regression model between the significant parameters and the simulated angle of repose. Finally，the measured angle of repose obtained under an inert atmosphere was taken as the target response， and the optimal DEM parameter combination was determined by minimizing the deviationbetween

simulated and experimental results.

Results and Discussion　Angle-of-repose tests on ten batches of NdFeB alloy powder showed an average value of 52. 45°，with relatively low variability and good repeatability，indicating that measurements under inert conditionsprovided a reliable basis for DEM calibration.The Plackett-Burman screening results demonstrated that the particle-particle coefficient of rolling friction（C）and particle-stainlesssteel coefficient of static friction（E）were statistically significant factors affecting flowability. Although the particle-particle coefficient of static friction（B）was only marginally significant，it was retained because of its clear physical relevance to interparticle resistance.On this basis，these three parameters were selected for further optimization. Steepest ascent experiments showed that the optimal region was located between the fourth and fifth test groups，which effectively narrowed the search range for response surface modeling.The subsequent Box-Behnken analysis indicated that the quadratic regression model was highly significant with no significant lack of fit，confirming that the model could adequately describe the relationship between contact parameters and the angle of repose.The analysis further showed that parameters of B，C，and E，as well as the interaction terms（BE and CE）and quadratic terms（B 2 and C 2 ），had significant effectsonthe response. Increasing B and C enhanced resistance to sliding and rolling，leading to a more stable particle-force-chain structure and a higher angle of repose.In addition，increasing E improved basal stability and reduced particle slip on the contact surface，enhancing pile stability. The optimized parameter set was determined to be 0.428 for B，0.13 for C，and 0.258 for E.Validation simulations using this parameter set produced an average angle of repose of 52. 8°，with a relative error of only 0. 66% compared with the experimental value， demonstrating that the calibrated model could reproduce the actual flow behavior of NdFeB alloy powder with high accuracy under inert-atmosphere conditions.

Conclusion　This study establishes an inert-atmosphere-based DEM calibration method for highly reactive NdFeB alloy powder and overcomes the limitation of conventional calibration approaches that rely on measurements performed after powder oxidation in air.By combining experimental flowability testing with Plackett-Burman screening，steepest ascent localization，and Box-Behnken quadratic regression，a reliable set of key contact parameters is obtained for the JKR-based DEM model.The calibrated model reproducesexperimentalresults with high accuracy and provides a reliable foundation for subsequent DEM simulations and optimization of NdFeB alloy powder processes，including handling，filling，molding，and related powder-metallurgy operations.

Keywords：NdFeB alloy； powder metallurgy； discrete element method； response surface methodology； parameter calibration

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