Tensile behavior of tailor rolled blanks with longitudinal thickness transition zone: Introducing a new tensile specimen

Abstract

In this study, a new design for tensile specimens made from tailor rolled blanks (TRB) with longitudinal thickness transition zone (TTZ) has been proposed. To this end, an additional lateral wedge angle is introduced to obtain a uniform stress field along the gauge length, which enables one to study the tailored properties of TRBs via stress-strain curves without considering the effects of geometrical inhomogeneities. Parallel finite element simulations were carried out to study the stress and strain fields resulted from different geometries of tensile specimens. The results were then used to obtain stress triaxiality factors to analyze the deformation prior to failure. In addition, a mathematical model was developed to study the contribution of different parts of TTZ to the total deformation. The results of uniaxial tension test along with results of simulation revealed that the deformation is controlled by the side with lower load-bearing ability in the new-developed tensile specimen. Furthermore, it was concluded that the conventional tensile specimens are more appropriate to study the effect of thickness changes on the elongation of TRBs. However, the presented tensile specimens can be used to study the strength of TRBs. Finally, the fracture mechanisms were investigated utilizing SEM and optical observations.