In dealing with abrasive waterjet machining(AWJM) simulation,most literatures apply finite element method(FEM) to build pure waterjet models or single abrasive particle erosion models.To overcome the mesh distorti...In dealing with abrasive waterjet machining(AWJM) simulation,most literatures apply finite element method(FEM) to build pure waterjet models or single abrasive particle erosion models.To overcome the mesh distortion caused by large deformation using FEM and to consider the effects of both water and abrasive,the smoothed particle hydrodynamics(SPH) coupled FEM modeling for AWJM simulation is presented,in which the abrasive waterjet is modeled by SPH particles and the target material is modeled by FEM.The two parts interact through contact algorithm.Utilizing this model,abrasive waterjet with high velocity penetrating the target materials is simulated and the mechanism of erosion is depicted.The relationships between the depth of penetration and jet parameters,including water pressure and traverse speed,etc,are analyzed based on the simulation.The simulation results agree well with the existed experimental data.The mixing multi-materials SPH particles,which contain abrasive and water,are adopted by means of the randomized algorithm and material model for the abrasive is presented.The study will not only provide a new powerful tool for the simulation of abrasive waterjet machining,but also be beneficial to understand its cutting mechanism and optimize the operating parameters.展开更多
The dependence between neutron skin thickness and neutron abrasion cross section (σnabr) for neutron-rich nuclei is investigated within the framework of the statistical abrasion ablation model. Assuming that the de...The dependence between neutron skin thickness and neutron abrasion cross section (σnabr) for neutron-rich nuclei is investigated within the framework of the statistical abrasion ablation model. Assuming that the density distributions for proton and neutron are of Fermi-type, and adjusting the diffuseness parameter of neutron density distribution in the droplet model, we find out the good linear correlation between the neutron skin thickness and the abrasion cross section σnabr for neutron-rich nuclei. The uncertainty of neutron skin thickness determined from σnabr is very small. It is suggested that σnabr can be used as a new experimental observable to extract the neutron skin thickness for neutronrich nucleus. The scaling behaviours between neutron skin thickness and σnabr, separately, for isotopes of ^26-35Na, ^44-56Ar, ^48-60Ca, ^67-78Ni are also investigated.展开更多
This study focuses on microstructural and micromechanical modeling of abrasive sliding contacts of wear-resistant Hadfield steel.3 D finite element representation of the microstructure was employed with a crystal plas...This study focuses on microstructural and micromechanical modeling of abrasive sliding contacts of wear-resistant Hadfield steel.3 D finite element representation of the microstructure was employed with a crystal plasticity model including dislocation slip,deformation twinning,and their interactions.The results showed that deformation twinning interacting with dislocations had a key role in the surface hardening of the material,and it was also important for the early hardening process of the sub-surface grains beyond the heavily distorted surface grains.The effects of grain orientation and microstructural features were discussed and analyzed according to the micromechanical model to give a perspective to the anisotropy of the material and the feasibility of using micromechanics in virtual material design.展开更多
基金supported by Shandong Provincial Natural Science Foundation of China (Grant No. Y2007A07)
文摘In dealing with abrasive waterjet machining(AWJM) simulation,most literatures apply finite element method(FEM) to build pure waterjet models or single abrasive particle erosion models.To overcome the mesh distortion caused by large deformation using FEM and to consider the effects of both water and abrasive,the smoothed particle hydrodynamics(SPH) coupled FEM modeling for AWJM simulation is presented,in which the abrasive waterjet is modeled by SPH particles and the target material is modeled by FEM.The two parts interact through contact algorithm.Utilizing this model,abrasive waterjet with high velocity penetrating the target materials is simulated and the mechanism of erosion is depicted.The relationships between the depth of penetration and jet parameters,including water pressure and traverse speed,etc,are analyzed based on the simulation.The simulation results agree well with the existed experimental data.The mixing multi-materials SPH particles,which contain abrasive and water,are adopted by means of the randomized algorithm and material model for the abrasive is presented.The study will not only provide a new powerful tool for the simulation of abrasive waterjet machining,but also be beneficial to understand its cutting mechanism and optimize the operating parameters.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10775168,10405032,10535010,10405033,10605036 and 10475108)the Shanghai Development Foundation for Science and Technology (Grant Nos 06QA14062,06JC14082 and 05XD14021)+1 种基金the State Key Program of Basic Research of China (Grant No 2007CB815004)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No KJCX3.SYW.N2)
文摘The dependence between neutron skin thickness and neutron abrasion cross section (σnabr) for neutron-rich nuclei is investigated within the framework of the statistical abrasion ablation model. Assuming that the density distributions for proton and neutron are of Fermi-type, and adjusting the diffuseness parameter of neutron density distribution in the droplet model, we find out the good linear correlation between the neutron skin thickness and the abrasion cross section σnabr for neutron-rich nuclei. The uncertainty of neutron skin thickness determined from σnabr is very small. It is suggested that σnabr can be used as a new experimental observable to extract the neutron skin thickness for neutronrich nucleus. The scaling behaviours between neutron skin thickness and σnabr, separately, for isotopes of ^26-35Na, ^44-56Ar, ^48-60Ca, ^67-78Ni are also investigated.
文摘This study focuses on microstructural and micromechanical modeling of abrasive sliding contacts of wear-resistant Hadfield steel.3 D finite element representation of the microstructure was employed with a crystal plasticity model including dislocation slip,deformation twinning,and their interactions.The results showed that deformation twinning interacting with dislocations had a key role in the surface hardening of the material,and it was also important for the early hardening process of the sub-surface grains beyond the heavily distorted surface grains.The effects of grain orientation and microstructural features were discussed and analyzed according to the micromechanical model to give a perspective to the anisotropy of the material and the feasibility of using micromechanics in virtual material design.