摘要
针对有限元法表征饲用油菜茎秆在切割过程的失效行为中,缺乏合理的茎秆Plastic_Kinematic模型失效准则参数的问题,提出通过试验测定及仿真模拟相结合的方法对茎秆剪切力值校准,合理推测失效模型参数的思路。基于P-K失效模型,应用LS-DYNA软件仿真模拟茎秆剪切的破坏过程,从模型失效准则参数中筛选出对剪切力值影响显著的参数,通过显著性分析得到应变率参数P、屈服应力和泊松比对茎秆最大剪切力具有显著性影响。利用Design-Expert数据处理软件,建立这3个关键因素与茎秆最大剪切力的回归方程,将试验测定的值作为仿真目标值代入回归方程中得到不同时期饲用油菜茎秆仿真模型参数。其中有差别的模型参数值分别为:抽薹期茎秆参数应变率参数P为6.44,屈服应力为10.01MPa,泊松比为0.34;盛花期茎秆参数应变率参数P为8.97,屈服应力为10.17MPa,泊松比为0.27;果荚期茎秆参数应变率参数P为9.47,屈服应力为15MPa,泊松比为0.23。无差别的参数有:密度为1100kg·m^(-3),弹性模量为1000MPa,剪切模量0.5MPa,硬化参数为0.05,应变率参数C为90,失效应变为0.03。对标定后的模型参数进行仿真验证试验,仿真试验茎秆在切碎过程的运动速度与实际台架试验所求的运动速度相对误差不大于6.97%,说明标定后的茎秆模型参数可用于有限元仿真试验。
Aiming at the problem of lack of reasonable failure criterion parameters of the Plastic_Kinematic model of the stalk in the simulation analysis of the failure behavior of the forage rapeseed stalk during the cutting process by the finite element method, the combination of test measurement and simulation was proposed to calibrate the shear force value of the stalk to reasonably predict the parameters of the failure model. Based on the P-K failure model, the LS-DYNA software was used to simulate the shearing failure process of stalk. The parameters that have significant impact on the shear force value were screened out from the parameters of the model failure criterion, and the significance analysis showed that the strain rate parameter P, yield stress and Poisson’s ratio had significant effects on the maximum shear force of the stalk. Using the Design-Expert software, the regression equation of the key factors and the maximum shear force of the stalks were established. The values measured in the experiment were substituted into the regression equation as the simulation target values, and the simulation model parameters of rapeseed stalks in different stages were obtained. The model parameters with different values are: the strain rate P of the stalk at the bolting period was 6.44, the yield stress was 10.01MPa, and the Poisson’s ratio was 0.34;the strain rate P of the stalk at the blooming period was 8.97, and the yield stress was 10.17MPa, the Poisson’s ratio was 0.27;the strain rate P of the stalk at the Pod period was 9.47, the yield stress was 15MPa, and the Poisson’s ratio was 0.23. The indifferent parameters were: the density was 1100kg·m^(-3), the elastic modulus was 1000MPa, the shear modulus was 0.5MPa, the hardening parameter was 0.05, the strain rate parameter C was 90, and the failure strain was 0.03.The simulation verification test was carried out on the calibrated model parameters, and the relative error between the movement speed of the stalk in the simulation test and the actual bench test
作者
蒋亚军
廖宜涛
廖庆喜
JIANG Ya-jun;LIAO Yi-tao;LIAO Qing-xi(School of Mechanical Engineering,Wuhan Polytechnic University,Wuhan 430023,China;College of Engineering,Huazhong Agricultural University,Wuhan 430070,China)
出处
《沈阳农业大学学报》
CAS
CSCD
北大核心
2022年第3期309-318,共10页
Journal of Shenyang Agricultural University
基金
湖北省教育厅指导性项目(B2021119)
武汉轻工大学校立科研项目(2021Y27)。
关键词
饲用油菜
茎秆
有限元法
参数标定
fodder rapeseed
stalk
finite element method
parameter calibration
