The accurate description of friction is critical in the finite element(FE)simulation of the sheet metal forming process.Usually,friction is oversimplified through the use of a constant Coulomb friction coefficient.In ...The accurate description of friction is critical in the finite element(FE)simulation of the sheet metal forming process.Usually,friction is oversimplified through the use of a constant Coulomb friction coefficient.In this study,the application of an existing multiscale friction model is extended to the hot stamping process.The model accounts for the effects of tool and sheet metal surface topography as well as the evolution of contact pressure,temperature,and bulk strain during hot stamping.Normal load flattening and strip drawing experiments are performed to calibrate the model.The results show that the model can relatively well predict friction in strip draw experiments when the tool surface evolution due to wear is incorporated.Finally,the application of the formulated multiscale friction model was demonstrated in the FE simulation of a hot-stamped part.展开更多
Tactile perception and friction can be modified by producing a deterministic surface topography.Change of surface feature arrangement and texture symmetry can produce an anisotropic frictional behaviour.It is generall...Tactile perception and friction can be modified by producing a deterministic surface topography.Change of surface feature arrangement and texture symmetry can produce an anisotropic frictional behaviour.It is generally achieved through skin hysteresis by promoting its deformation.This work investigates whether a bidirectional friction can be created with microscale ellipsoidal asperity textures,thus relying on the adhesive component of friction.For this purpose,four textured samples with various asperity dimensions were moulded with a silicone rubber having an elastic modulus comparable to that of the skin.Coefficient of friction measurements were conducted in-vivo in two sliding directions with a range of normal loads up to 4 N.Finite element method(FEM)was used to study elastic deformation effects,explain the observed friction difference,and predict surface material influence.Measurements performed perpendicular to the asperity major radii showed consistently higher friction coefficients than that during parallel sliding.For the larger asperity dimensions,a change of the sliding direction increased friction up to a factor of 2.The numerical analysis showed that this effect is mostly related to elastic asperity deflection.Bidirectional friction differences can be further controlled by asperity dimensions,spacing,and material properties.展开更多
文摘The accurate description of friction is critical in the finite element(FE)simulation of the sheet metal forming process.Usually,friction is oversimplified through the use of a constant Coulomb friction coefficient.In this study,the application of an existing multiscale friction model is extended to the hot stamping process.The model accounts for the effects of tool and sheet metal surface topography as well as the evolution of contact pressure,temperature,and bulk strain during hot stamping.Normal load flattening and strip drawing experiments are performed to calibrate the model.The results show that the model can relatively well predict friction in strip draw experiments when the tool surface evolution due to wear is incorporated.Finally,the application of the formulated multiscale friction model was demonstrated in the FE simulation of a hot-stamped part.
基金This work was supported by INTERREG V-A Deutschland-Nederland program MOVERO under the project number 142091.
文摘Tactile perception and friction can be modified by producing a deterministic surface topography.Change of surface feature arrangement and texture symmetry can produce an anisotropic frictional behaviour.It is generally achieved through skin hysteresis by promoting its deformation.This work investigates whether a bidirectional friction can be created with microscale ellipsoidal asperity textures,thus relying on the adhesive component of friction.For this purpose,four textured samples with various asperity dimensions were moulded with a silicone rubber having an elastic modulus comparable to that of the skin.Coefficient of friction measurements were conducted in-vivo in two sliding directions with a range of normal loads up to 4 N.Finite element method(FEM)was used to study elastic deformation effects,explain the observed friction difference,and predict surface material influence.Measurements performed perpendicular to the asperity major radii showed consistently higher friction coefficients than that during parallel sliding.For the larger asperity dimensions,a change of the sliding direction increased friction up to a factor of 2.The numerical analysis showed that this effect is mostly related to elastic asperity deflection.Bidirectional friction differences can be further controlled by asperity dimensions,spacing,and material properties.
