Sheet necking prediction in forming limit diagrams with the anisotropy influence incorporation

Abstract

A well-known method of materials formability description is the Forming Limit Diagram (FLD). In FLDs/FLC (Forming Limit Curve) a plot of major and minor principal strains in the plane of deformed sheet where necking takes place is represented. The current paper is dealing with anisotropy influence on FLC. This effect is going to be studied with the use of mild steel DC01. Hills anisotropic criterion is considered here and for its application experimental investigation has to be carried out in order to provide input data for the model applied. Uniaxial tensile tests were performed for basic characterisation of sheet samples with the use of contact-less measuring devices. In order to assess the anisotropy experimentally, the specimens were extracted and tested in Rolling Direction (RD), Transverse Direction (TD) and 45° Skew Direction (SD) for the Lankford ratios determination. Detailed stress state description of the material investigated was carried out with the use the stress triaxiality and Lode angle parameter. Therefore, transformations from conventional space into stress state provide a profound insight into the necking phenomenon. According to the experimental and numerical results it was found that it is necessary to take anisotropy effects into account for the material investigated.Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Determining Forming Limit Diagrams Using Sub-Sized Specimen Geometry and Comparing FLD Evaluation Methods

“…Their intersection provides the point of the beginning of necking (Figure 3). This methodology is widely accepted and included in the standard evaluation of Aramis DIC systems [15,16].…”

“…Their intersection provides the point of the beginning of necking (Figure 3). This methodology is widely accepted and included in the standard evaluation of Aramis DIC systems [15,16]. It is worth mentioning that when the results originate from any method evaluating the fracture strain, the final diagram is called a fracture forming limit diagram (FFLD or It is worth mentioning that when the results originate from any method evaluating the fracture strain, the final diagram is called a fracture forming limit diagram (FFLD or F-FLD).…”