The effects of forming damage are analyzed,which occur during hot stamping process,on the load-carrying capacity and failure mode of hot stamped beams.A damage-coupled pre-forming constitutive model was proposed,in wh...The effects of forming damage are analyzed,which occur during hot stamping process,on the load-carrying capacity and failure mode of hot stamped beams.A damage-coupled pre-forming constitutive model was proposed,in which the damage during hot stamping process was introduced into the service response.The constitutive model was applied into the three-point bending simulation of a hot stamped beam,and then the influences of forming damage on the load-carrying capacity and cracks propagation were investigated.The results show that the forming damage reduces the maximum load capacity of the hot stamped beam by 7.5%.It also causes the crack to occur earlier and promotes crack to propagate along the radial direction of the punch.展开更多
To further investigate the forming mechanism and springback characteristics of strips under multi-square punch forming (MSPF) considering partial-unloading effects, a series of concave form ing tests of strips are con...To further investigate the forming mechanism and springback characteristics of strips under multi-square punch forming (MSPF) considering partial-unloading effects, a series of concave form ing tests of strips are conducted on the MSPF machine. This paper aims to reveal the physical mecha nism of the elastic-plastic deformation in the MSPF process considering the effect of the forming ap proaches, and derive appropriate mathematical interpretations. The theoretical model is firstly estab lished to analyse the concave forming mechanism and springback characteristics of the strip, and its accuracy is then validated by experimental data. The forming history and load evolutions are depicted to explore the required forming capacity through the proposed analytical method. Besides, the paramet ric studies are carried out to discuss their effects on the springback of the strip. The results suggest that the deformation paths of the strip are influenced by the forming approach, and the springback of the strip in convex forming is larger than that in concave forming.展开更多
通过耦合计算流体力学(computational fluid dynamics,CFD)与离散单元法(discrete element method,DEM),对球柱状颗粒在90°弯管中的气力输送过程进行了数值模拟研究。重点分析了入口气体速度、颗粒质量流量、颗粒长径比和管道直径...通过耦合计算流体力学(computational fluid dynamics,CFD)与离散单元法(discrete element method,DEM),对球柱状颗粒在90°弯管中的气力输送过程进行了数值模拟研究。重点分析了入口气体速度、颗粒质量流量、颗粒长径比和管道直径等参数对管道压降、出口处平均颗粒速度、平均颗粒碰撞次数和碰撞强度等指标的影响规律。结果显示,不同参数组合对系统的输送性能有较大影响,系列定量结果加深了对球柱状颗粒在90°弯管中气力输送特性的认识,并对提高其气力输送效率有指导意义。展开更多
基金Supported by the National Natural Science Foundation of China(5137520151775227)。
文摘The effects of forming damage are analyzed,which occur during hot stamping process,on the load-carrying capacity and failure mode of hot stamped beams.A damage-coupled pre-forming constitutive model was proposed,in which the damage during hot stamping process was introduced into the service response.The constitutive model was applied into the three-point bending simulation of a hot stamped beam,and then the influences of forming damage on the load-carrying capacity and cracks propagation were investigated.The results show that the forming damage reduces the maximum load capacity of the hot stamped beam by 7.5%.It also causes the crack to occur earlier and promotes crack to propagate along the radial direction of the punch.
文摘To further investigate the forming mechanism and springback characteristics of strips under multi-square punch forming (MSPF) considering partial-unloading effects, a series of concave form ing tests of strips are conducted on the MSPF machine. This paper aims to reveal the physical mecha nism of the elastic-plastic deformation in the MSPF process considering the effect of the forming ap proaches, and derive appropriate mathematical interpretations. The theoretical model is firstly estab lished to analyse the concave forming mechanism and springback characteristics of the strip, and its accuracy is then validated by experimental data. The forming history and load evolutions are depicted to explore the required forming capacity through the proposed analytical method. Besides, the paramet ric studies are carried out to discuss their effects on the springback of the strip. The results suggest that the deformation paths of the strip are influenced by the forming approach, and the springback of the strip in convex forming is larger than that in concave forming.
文摘通过耦合计算流体力学(computational fluid dynamics,CFD)与离散单元法(discrete element method,DEM),对球柱状颗粒在90°弯管中的气力输送过程进行了数值模拟研究。重点分析了入口气体速度、颗粒质量流量、颗粒长径比和管道直径等参数对管道压降、出口处平均颗粒速度、平均颗粒碰撞次数和碰撞强度等指标的影响规律。结果显示,不同参数组合对系统的输送性能有较大影响,系列定量结果加深了对球柱状颗粒在90°弯管中气力输送特性的认识,并对提高其气力输送效率有指导意义。
