为了解决当前存在的区间运算复杂性高、普通区间迭代程序运算量大、花费机器时间长等问题,提高区间迭代的运算效率,针对单变元多项式方程的求解展示了一个高效的区间Newton迭代算法。该算法利用1维问题多维化的思想加快迭代的收敛速度,...为了解决当前存在的区间运算复杂性高、普通区间迭代程序运算量大、花费机器时间长等问题,提高区间迭代的运算效率,针对单变元多项式方程的求解展示了一个高效的区间Newton迭代算法。该算法利用1维问题多维化的思想加快迭代的收敛速度,改进了多维化过程中出现的性能拖累,极大地提高了算法在实际应用中的执行效率。算法已经被实现为M ap le程序,实验数据表明,与现有的算法相比,这个算法的迭代次数和运行时间都大幅减少,充分显示了它的高效性。展开更多
In order to study the interaction between various fouling particles and ballast,a multi-layer and multi-scale discrete element model(DEM)including the sleeper,ballast bed and the surface layer of subgrade was develope...In order to study the interaction between various fouling particles and ballast,a multi-layer and multi-scale discrete element model(DEM)including the sleeper,ballast bed and the surface layer of subgrade was developed.Two typical fouling particles,the hard particles(sand)and soft ones(coal fines),are considered.A support stiffness test of the ballast bed under various fouling conditions was conducted to calibrate the microscopic parameters of the contact model.With the model,the influence of fouling particles on the mechanical behavior and deformation of the ballast bed was analyzed from macro and micro perspectives.The results show that the increase in the strength of the fouling particles enlarges the stiffness of the ballast bed.Hard particles increase the uniformity coefficient of the contact force bondγof ballast by 50.4%.Fouling particles increase the average stress in the subgrade,soft particles by 2 kPa and hard particles by 1 kPa.Hard particles can reduce the elasticity,plastic deformation and energy dissipation in the track structure.As the fouling particle changes from hard to soft,the proportion of the settlement in ballast bed increases to 40.5%and surface layer of swbgrade settlement decreases to 59.5%.Thus,the influence of fouling particles should be considered carefully in railway design and maintenance.展开更多
文摘为了解决当前存在的区间运算复杂性高、普通区间迭代程序运算量大、花费机器时间长等问题,提高区间迭代的运算效率,针对单变元多项式方程的求解展示了一个高效的区间Newton迭代算法。该算法利用1维问题多维化的思想加快迭代的收敛速度,改进了多维化过程中出现的性能拖累,极大地提高了算法在实际应用中的执行效率。算法已经被实现为M ap le程序,实验数据表明,与现有的算法相比,这个算法的迭代次数和运行时间都大幅减少,充分显示了它的高效性。
基金Project(51978045) supported by the National Natural Science Foundation of ChinaProject([2017]7) supported by Shenshuo Science and Technology Development Project,China。
文摘In order to study the interaction between various fouling particles and ballast,a multi-layer and multi-scale discrete element model(DEM)including the sleeper,ballast bed and the surface layer of subgrade was developed.Two typical fouling particles,the hard particles(sand)and soft ones(coal fines),are considered.A support stiffness test of the ballast bed under various fouling conditions was conducted to calibrate the microscopic parameters of the contact model.With the model,the influence of fouling particles on the mechanical behavior and deformation of the ballast bed was analyzed from macro and micro perspectives.The results show that the increase in the strength of the fouling particles enlarges the stiffness of the ballast bed.Hard particles increase the uniformity coefficient of the contact force bondγof ballast by 50.4%.Fouling particles increase the average stress in the subgrade,soft particles by 2 kPa and hard particles by 1 kPa.Hard particles can reduce the elasticity,plastic deformation and energy dissipation in the track structure.As the fouling particle changes from hard to soft,the proportion of the settlement in ballast bed increases to 40.5%and surface layer of swbgrade settlement decreases to 59.5%.Thus,the influence of fouling particles should be considered carefully in railway design and maintenance.
