热固性保温塑料粉末离散元参数的标定与应用

Parameter Calibration and Application of Discrete Element of Thermosetting Insulation Plastic Powder

为准确模拟热固性保温塑料粉末的混合程度,提出了以热固性聚氨酯超细粉末堆积角为响应值,基于响应面优化标定热固性聚氨酯粉末离散元关键接触参数的方法。引入了JKR模型的尺度变换准则,采用了MATLAB图像处理技术与Box-Behnken试验设计相结合的方式,对热固性聚氨酯粉末颗粒间的关键接触参数(碰撞恢复系数、静摩擦系数以及JKR表面能)进行了模拟标定。根据仿真试验结果建立了堆积角与关键接触参数的二阶回归模型并优化,以真实堆积角为目标值仿真求得关键接触参数的最佳组合为碰撞恢复系数0.35、静摩擦系数0.74、JKR表面能5.7 J/m^(2)。将仿真得到的堆积角与真实试验值进行对比验证,误差在±2°以内,二者无显著性差异;将最优离散元参数应用于粉末机械混合再生制备试验。结果表明,热固性聚氨酯塑料粉末随机混合效果接近均匀状态。获得综合性能较优的再生复合保温板,验证了粉末细料离散元参数标定方法的可行性。

In order to accurately simulate the mixing degree of thermosetting insulation plastic powder,a method was proposed to calibrate the key contact parameters of discrete element of thermosetting polyurethane powder based on the response surface,taking the stacking angle of thermosetting polyurethane ultrafine powder as the response value.The scale transformation criterion of the JKR model is introduced,and the key contact parameters(collision recovery coefficient,static friction coefficient and JKR surface energy)between thermosetting polyurethane powder particles are simulated and calibrated using MATLAB and Box-Behnken design.With the simulation results,a second-order regression model of the stacking angle and key contact parameters is established and optimized.Taking the real stacking angle as the target value,the optimal key contact parameter combination is obtained when the collision recovery coefficient is 0.35,the static friction coefficient is 0.74 and the JKR surface energy is 5.7 J/m^(2).The stacking angle obtained by simulation is compared with the real test value,and the error is within±2°.The optimal parameter combination is applied to the powder mechanical mixing regeneration experiment,and the results show that the random mixing effect of thermosetting polyurethane plastic powder is close to the homogeneous state.The recycled composite insulation board with good comprehensive performance is obtained,proving the feasibility of the parameter calibration method of the discrete element for the fine powder.