Choosing inner door panel of auto as an example, the two stage deep drawing of complex sheet metal was studied. By using CAD software UG and numerical simulation software DYNAFORM, the characteristic of the CAD modeli...Choosing inner door panel of auto as an example, the two stage deep drawing of complex sheet metal was studied. By using CAD software UG and numerical simulation software DYNAFORM, the characteristic of the CAD modeling of the simple workpiece and the complex sheet metal, finite element modeling and the selection of parameters were analyzed. The effects of three important material parameters such as yield stress, strain hardening exponent and normal anisotropic parameter on the formability of the two stage deep drawing of inner door panel of auto were investigated. The results show that the yield stress has large influence on the increase of thickness, while the strain hardening exponent has little effect on the thickness change. Otherwise, larger normal anisotropic parameter can result in a better formability of the sheet.展开更多
The calculation method of forming limit of sheet metals based on M-K instability theory is proposed,and the method is applicable to different yield criterions and hardening models.The forming limit dia-grams of AA5754...The calculation method of forming limit of sheet metals based on M-K instability theory is proposed,and the method is applicable to different yield criterions and hardening models.The forming limit dia-grams of AA5754-O,AA6111-T4 aluminum alloy sheet and DP steel sheet under combined loading paths are obtained based on mixed hardening model with YLD2000-2D yield criterion proposed by Barlat in 2003 and L-C nonlinear kinematic hardening model proposed by Lemaitre and Chaboche.The results show that the forming limit diagram made up of limit strain(FLD-strain) is evidently influenced by the loading path.The forming limit diagram made up of limit stress(FLD-stress) is also influenced by loading path and it is not an only curve,which differs from the conventional view.The degree of the influence of loading path on FLD-stress is related with pre-strain.The larger the pre-strain is,the greater the influence of loading path on FLD-stress will be.The change of FLD-stress is small only when pre-strain is small.In addition,the hardening behavior of the material will influence the path-dependence of FLD-stress:The larger the proportion of kinematic hardening in the whole hard-ening is,namely the more obvious Bauschinger effect of the material,the greater the influence of loading path on FLD-stress will be.展开更多
文摘Choosing inner door panel of auto as an example, the two stage deep drawing of complex sheet metal was studied. By using CAD software UG and numerical simulation software DYNAFORM, the characteristic of the CAD modeling of the simple workpiece and the complex sheet metal, finite element modeling and the selection of parameters were analyzed. The effects of three important material parameters such as yield stress, strain hardening exponent and normal anisotropic parameter on the formability of the two stage deep drawing of inner door panel of auto were investigated. The results show that the yield stress has large influence on the increase of thickness, while the strain hardening exponent has little effect on the thickness change. Otherwise, larger normal anisotropic parameter can result in a better formability of the sheet.
基金Supported by the National Natural Science Foundation of China (Grant No. 50475004)
文摘The calculation method of forming limit of sheet metals based on M-K instability theory is proposed,and the method is applicable to different yield criterions and hardening models.The forming limit dia-grams of AA5754-O,AA6111-T4 aluminum alloy sheet and DP steel sheet under combined loading paths are obtained based on mixed hardening model with YLD2000-2D yield criterion proposed by Barlat in 2003 and L-C nonlinear kinematic hardening model proposed by Lemaitre and Chaboche.The results show that the forming limit diagram made up of limit strain(FLD-strain) is evidently influenced by the loading path.The forming limit diagram made up of limit stress(FLD-stress) is also influenced by loading path and it is not an only curve,which differs from the conventional view.The degree of the influence of loading path on FLD-stress is related with pre-strain.The larger the pre-strain is,the greater the influence of loading path on FLD-stress will be.The change of FLD-stress is small only when pre-strain is small.In addition,the hardening behavior of the material will influence the path-dependence of FLD-stress:The larger the proportion of kinematic hardening in the whole hard-ening is,namely the more obvious Bauschinger effect of the material,the greater the influence of loading path on FLD-stress will be.
