Recent development and applications of the Gurson model

With increasing requirements on the crash safety of automotive components and on virtual prototyping it becomes more and more important to model damage behaviour of structural components in crash simulations. Especially high strength steels show a lower ductility in comparison with conventional steels. To predict the damage behaviour an evaluation chain including material charaterization, numerical simulation with a suitable damage model and verification by component tests was established. To vary the stress triaxiality notched flat tensile specimens and Iosipescu shear specimens were tested. The damage behaviour depends strongly on the loading type (stress triaxiality) and cannot be modelled with simple damage models based on one constant fracture strain. In this work, the Gurson model and the Wilkins model have been applied to describe the damage behaviour and failure in crash simulations. The Gurson model has been extended by Johnson-Cook’s law in order to improve the ability to represent shear dominated failure. Special experimental techniques for material characterisation and component tests were developed. The applied damage concept was verified in terms of examples, i.e. a motor carrier of an aluminium die cast alloy and a B-column of a high strength steel.

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