Netherlands: PhD position Investigating the anelstic behaviour of Advanced High Strength Steels

Deadline: 31 Jan. 2013

Job description

Automotive industry is increasing the use of Advanced High Strength Steels (AHSS) to reduce the weight of vehicles. The major hurdle in employing AHSS is the change in geometry after releasing a part from the dies. This so-called springback is related to elastic and anelastic relaxation. Currently, this cannot be predicted accurately and hence multiple expensive and time consuming re-works of the stamping dies are needed.

AHSS have a high strength and therefore thinner sheet can be used. Both aspects increase the degree of springback, hence springback-related issues are of major importance for understanding and using this class of materials. The overall elastic (reversible) behaviour is not fully represented by the atomic interactions reflected in the elasticity modulus (as currently assumed in simulation software) but also depends on the degree of prior plastic deformation.  Accurate prediction of the unloading-reloading behaviour should be based on the understanding of the elastic and anelastic behaviour of the material after plastic deformation.

The aim of this research is to capture the unloading-reloading behaviour in a physically based material model. The underlying elastic and anelastic material behaviour, which is dependent on prior plastic deformation through the dislocation structure, must be implemented in modelling the loading-unloading-reloading cycle. Besides, the influence of deformation mode, elevated temperature and time must be accounted for. An extensive experimental research program has to be set up in this project to characterize the effective elasticity modulus and loading-unloading-reloading behaviour of Advanced High-Strength Steels. A physically based material model will be developed and calibrated based on the experimental results. This model will supply a fundamental basis for the reversible behaviour of these steels and thus improve the predictability of springback simulations of AHSS automotive parts.

Information and application

More information on this PhD position can be obtained from prof.dr.ir. A.H. (Ton) van den Boogaard (a.h.vandenboogaard@utwente.nl, +31 53 489 4785).