The most often used friction model for sheet metal forming simulations is the relative simple Coulomb friction model. This paper presents a more advanced friction model for large scale forming simulations based on the surface change on the micro-scale. The surface texture of a material changes if two surfaces are in contact under a normal load which is an effect of flattening due to normal load...

The single point incremental forming (SPIF) is one of the dieless forming processes which is widely used in the sheet metal forming. The correct selection of the SPIF parameters influences the formability and quality of the product. In the present study, the Gurson-Tvergaard Needleman (GTN) damage model was used for the fracture prediction in the numerical simulation of the SPIF process of alum...

Flexible forming is a sheet metal forming process with the application of soft material tooling. In this study, flexible (silicone rubber, SR, and styrene butadiene rubber, SBR) and semi-rigid (polyamide 66, PA) polymeric materials were adopted to make several upper dies which were used in combination with aluminium lower dies. Stamping operations were performed on a thin aluminium alloy sheet ...

In Incremental Sheet Forming (ISF) strains can be obtained well above the Forming Limit Curve (FLC) that is applicable to common sheet forming operations like deep drawing and stretching. This paper presents an overview of mechanisms that have been suggested to explain the enhanced formability. The difference between fracture limit and necking limit in sheet metal forming is discussed. The neck...

The purpose of this investigation is to examine the viability of using the sheet metal for forming applications. Forming limit diagram (FLD) composed of negative and positive minor strain with respect to major strain which occurs at directional zero strain with the critical thickness of sheet metal. The negative minor strain region of FLD is predicted by localized necking. However there is no d...

ultrasonic vibration assisted single point incremental forming (uvaspif) process is an attractive and adaptive method in which a sheet metal is gradually and locally formed by a vibrating hemispherical-head tool. the ultrasonic excitation of forming tool reduces the average of vertical component of forming force and spring-back rate of the formed sample. the spring-back phenomenon is one of the...

this paper investigates the forming of sheet metal forming under cycling loading by considering the bauschinger effect. different proposed plasticity models which can handle this kind of deformation process have been reviewed in details. for instance, isotropic, kinematic and combined forms in the linear and non-linear cases including the well-known yoshida and chaboche's models have been ...