Suttner, Sebastian

Profile

Projects

• Contribution to an efficient FE-based design of magnesium sheet parts

• Contribution to an efficient FE-based design of magnesium sheet parts

  
  (Third Party Funds Single)
  Abstract

  Light weight construction is for automotive manufactures a known strategy in order to reduce car´s weight, fuel consumption and overall greenhouse emissions. In order to meet these targets the use of aluminum alloy as well as higher- and high-strength steels has increasingly become a standard for series production. Magnesium has struggled for acceptance despite the low density, mainly due to the lack of knowledge of its unusual plastic behavior and the absence of adequate material models in commercial FE-programs. The mission of the present research project is to implement and further develop an efficient material model for magnesium sheets in order to overcome this deficit. For this purpose, the constitutive material model called TWINLAW from Li et al. (2010) will be implemented in ABAQUS/Standard using a UMAT subroutine. The von Mises yield criterion of the model in its original form will be substitute by an advanced anisotropic yield criterion to address the pronounced anisotropy of the material. The implementation of the only partially described model together with its further development represents a challenging task. In fact, the whole constitutive model will be impacted by the adoption of an advanced anisotropic yield criterion and will likely undergo a major rework. It is among other things expected that the integration algorithm will be changed because of the complexity of the new flow surface. Supplementary to Li et al. (2010) whose investigations were carried out at room temperature only, the model will be isothermally tested at enhanced temperatures. This validation in a relevant forming technology temperature range will be performed using already implemented as well as new experimental methods.
  →More information

• Characterization and evaluation of yield loci and subsequent yield loci considering isotropic-kinematic hardening

  
  (Third Party Funds Single)
  Abstract

  1.424 / 5.000ÜbersetzungsergebnisseWhen using the numerical analysis of forming processes, the influence of the material model used is of fundamental importance. In terms of accuracy, both the selected yield law and its development as a function of the degree of deformation play an important role in the calculation. Especially in the case of non-linear strain paths, the kinematic hardening becomes more important with regard to the shape of the subsequent yield locus. Within the scope of this project, the isotropic-kinematic hardening behavior should be the focus of the experimental and analytical investigations and various approaches to hardening models should be scientifically analyzed and evaluated. By extending and expanding the test rig to determine the start of yielding, tensile tests with cruciform specimen are carried out in order to be able to set defined non-linear load paths for the determination of subsequent yield loci. In addition, the Bauschinger coefficient, which is crucial for modeling of the kinematic hardening behavior, is determined through tests with alternating loads. These experimentally determined data are evaluated and qualified with the implemented isotropic-kinematic hardening models. As a result, a test methodology is developed that enables the best possible modeling with minimal experimental effort at the same time.
  →More information

Publications