The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/stra...The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The one-step forward simulations of compression and rolling processes were presented as examples,and the results were compared with those obtained by classical incremental FE simulation to verify the feasibility and validity of the proposed method.展开更多
Aluminum laminate is one kind of the rigidizable composite materials and plays an important role in construction of the inflatable space structure(ISS),which has potential application in space in the future.But the st...Aluminum laminate is one kind of the rigidizable composite materials and plays an important role in construction of the inflatable space structure(ISS),which has potential application in space in the future.But the study of the predecessors mainly focuses on the research of the mechanical behavior in the room temperature,for this reason,mechanical properties of the aluminum laminate in low-high temperature have been studied in this paper.The failure mechanism of the aluminum laminate is also analyzed in the microscopic view by JCXA-T33 electron probe.The results show uhat the temperature has significant influence on the strength and Young's modulus of the aluminum laminate.With the increase of temperature,both the strength and Young's modulus of the aluminum laminate decrease.A model between Young's modulus of the aluminum laminate and temperatures is obtained by using Arrhenius equation.The predicted values by the model agree well with the experiment values.展开更多
The dispersion behavior and spatial distribution of nanoparticles(NPs)in ring polymer melts are explored by using molecular dynamics(MD)simulations.As polymer-NP interactions increase,three general categories of polym...The dispersion behavior and spatial distribution of nanoparticles(NPs)in ring polymer melts are explored by using molecular dynamics(MD)simulations.As polymer-NP interactions increase,three general categories of polymer-mediated NP organization are observed,namely,contact aggregation,bridging,and steric dispersion,consistent with the results of equivalent linear ones in previous studies.In the case of direct contact aggregation among NPs,the explicit aggregation-dispersion transition of NPs in ring polymer melts can be induced by increasing the chain stiffness or applying a steady shear flow.Results further indicate that NPs can achieve an optimal dispersed state with the appropriate chain stiffness and shear flow.Moreover,shear flow cannot only improve the dispersion of NPs in ring polymer melts but also control the spatial distribution of NPs into a well-ordered structure.This improvement becomes more evident under stronger polymer-NP interactions.The observed induced-dispersion or ordered distribution of NPs may provide efficient access to the design and manufacture of high-performance polymer nanocomposites(PNCs).展开更多
基金Project(50575143)supported by the National Natural Science Foundation of ChinaProject(20040248005)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The one-step forward simulations of compression and rolling processes were presented as examples,and the results were compared with those obtained by classical incremental FE simulation to verify the feasibility and validity of the proposed method.
文摘Aluminum laminate is one kind of the rigidizable composite materials and plays an important role in construction of the inflatable space structure(ISS),which has potential application in space in the future.But the study of the predecessors mainly focuses on the research of the mechanical behavior in the room temperature,for this reason,mechanical properties of the aluminum laminate in low-high temperature have been studied in this paper.The failure mechanism of the aluminum laminate is also analyzed in the microscopic view by JCXA-T33 electron probe.The results show uhat the temperature has significant influence on the strength and Young's modulus of the aluminum laminate.With the increase of temperature,both the strength and Young's modulus of the aluminum laminate decrease.A model between Young's modulus of the aluminum laminate and temperatures is obtained by using Arrhenius equation.The predicted values by the model agree well with the experiment values.
基金Project supported by the National Natural Science Foundation of China(Nos.21674082 and 21973070)the Natural Science Foundation of Zhejiang Province(No.LY19B040006),China。
文摘The dispersion behavior and spatial distribution of nanoparticles(NPs)in ring polymer melts are explored by using molecular dynamics(MD)simulations.As polymer-NP interactions increase,three general categories of polymer-mediated NP organization are observed,namely,contact aggregation,bridging,and steric dispersion,consistent with the results of equivalent linear ones in previous studies.In the case of direct contact aggregation among NPs,the explicit aggregation-dispersion transition of NPs in ring polymer melts can be induced by increasing the chain stiffness or applying a steady shear flow.Results further indicate that NPs can achieve an optimal dispersed state with the appropriate chain stiffness and shear flow.Moreover,shear flow cannot only improve the dispersion of NPs in ring polymer melts but also control the spatial distribution of NPs into a well-ordered structure.This improvement becomes more evident under stronger polymer-NP interactions.The observed induced-dispersion or ordered distribution of NPs may provide efficient access to the design and manufacture of high-performance polymer nanocomposites(PNCs).
