A comparison between Stepwise Modelling and Inverse Modelling methods for characterization of press hardened sheet metals.
Number of Authors: 3
2017 (English)In: Hot Sheet Metal Forming of High-performance Steel / [ed] Oldenburg, M. and Steinhoff, K.and Prakash, B., 2017Conference paper (Refereed)
The demand for weight reduction of cars has increased the number of press hardened sheet metal parts used in the automotive industry. This leads to an increased demand on the precision of simulations of press hardened sheet metals. An accurate prediction of the post-necking behaviour of materials is therefore needed to increase the precision of computer simulations with large deformations, as for example in forming simulations and crash simulations. Especially fracture simulations of press hardened steel parts with tailored properties have a huge demand on precise material models.
Inverse modelling is a common engineering tool to characterize the elasto-plastic behaviour of materials. Taking experimental data, such as force and displacement data, the material model parameters are optimised until the simulated output reaches a target function. Then inverse modelling is highly time demanding and needs nonlinear hardening material models.
Lately a new fast method for post necking characterisation of sheet metals, called the Stepwise Modelling Method (SMM), was presented. This method uses full field measurements to obtain the strain field on the surface of sheet metal tensile specimens. Furthermore, the stepwise modelling method models an experimental hardening curve in a stepwise process. This hardening curve is a piecewise linear curve and not restricted to any specific material model.
In this paper SMM is used to characterize the hardening behaviour for thermally treated boron steel. These results are compared with the results of inverse modelling. Three different material models are used. The comparison shows a minor deviation in the resulting hardening relations between stepwise modelling and inverse modelling. Since the efficiency is an important factor in product development calculation times are taken into account. Comparing calculation time using SMM is considerably more efficient than using inverse modelling. Furthermore another advantage of SMM is shown in the fact that the piecewise linear hardening curves can be fitted to almost any material model without computational costs.
Place, publisher, year, edition, pages
Stepwise modelling; Inverse modelling; Material characterisation; Boron steel; Press hardening; Material modelling
Manufacturing, Surface and Joining Technology Vehicle Engineering Metallurgy and Metallic Materials Applied Mechanics
Research subject Solid Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-62459OAI: oai:DiVA.org:ltu-62459DiVA: diva2:1081228
6th International Conference on Hot Sheet Metal Forming of High-Performance Steel, CHS2-2017, Atlanta, 04 - 07 June 2017