考虑接触半径的离散元BPM模型参数标定  

Parameter Calibration of Discrete Element BPM Model Considering Contact Radius

作　　者：张延军[1] 孙融 张帅[1] 许鹏 王春艳 ZHANG Yan-jun;SUN Rong;ZHANG Shuai;XU Peng;WANG Chun-yan(School of Mechanical Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学机械工程学院,太原030024

出　　处：《太原科技大学学报》2023年第2期148-154,共7页Journal of Taiyuan University of Science and Technology

基　　金：山西省重点研发计划(201903D121041);山西省高等学校优秀青年学术带头人支持计划(20191044)。

摘　　要：离散元BPM模型广泛应用于岩石等脆性材料的模拟仿真,在应用BPM模型前需要用大量的仿真实验进行参数标定工作,存在标定过程复杂随机性大的问题,研究不同参数对BPM模型的影响很有必要。对此采用单因素控制变量法讨论接触半径以及临界切、法向应力对整个标定过程的影响,对比分析不同临界切、法向应力下接触半径过小的局限性,并模拟接触半径为1.1R~2.0R下模型的破坏特征,讨论不同接触半径下模型的应力分布状况以及黏结键断裂因素。结果认为接触半径是影响模型应力分布的关键因素之一,选取合适的接触半径可更好的表征煤岩特性。基于EDEM软件与BPM模型理论,提出参数标定的经验方法,选取真实煤岩的实验室数据,通过虚拟的单轴压缩实验,对上述方法进行验证。结果显示当接触半径、法向刚度、切向刚度、临界法向应力、临界切向应力分别取:1.5 R、3.16×10^(8)、1.26×10^(8)、2.8×10^(6)、4×10^(6)时与实验值拟合良好,并在仿真过程发现选取合适的接触半径,可较好的表现出材料性能。该方法为离散元参数标定工作提供新的思考。The discrete element BPM model is widely used in the simulation of brittle materials such as rocks.Before applying the BPM model,it is necessary to use a large number of simulation experiments for parameter calibration.Due to the complexity and randomness of the calibration process,the single-factor control variable method is used to focus on the influence of the contact radius,critical tangent and normal stress on the entire calibration process.Comparative analysis of the limitation of too small contact radius under different critical tangents and normal stresses,and the failure characteristics of the model under the contact radius of 1.1 R-2.0R are listed,and the stress distribution of the model under different contact radii and bond fracture factor are discussed.The results indicate that the contact radius is one of the key factors affecting the stress distribution of the model.An appropriate contact radius can better characterize the characteristics of coal and rock.Based on EDEM software and combined with BPM model theory,an empirical method for parameter calibration is proposed,real laboratory data of coal and rock is chosen,and the above method through virtual uniaxial compression experiments is verified.The results show that when the contact radius,normal stiffness,tangential stiffness,critical normal stress,critical tangential stress are respectively taken as:1.5 R,3.16×10^(8),1.26×10^(8),2.8×10^(6),4×10^(6),a good fit effect with the experimental values can be obtained.And it is found that the proper contact radius can better show the performance of the material in the experiment process.This method provides new ideas for the calibration of discrete element parameters.

关 键 词：单轴压缩 参数标定 接触半径 离散元法 BPM 黏结键断裂条件 

分 类 号：TD315[矿业工程—矿井建设]