The body structure of current passenger cars can have up to 51 pct of AHSS and this percentage might grow up to 65 pct in upcoming vehicles.
The use of these steels for structural and safety related automotive components is undergoing a continuous increase in the last years. Furthermore, a physically motivated fracture criterion for edge-cracking prediction, based on thickness strain measurements in fatigue pre-cracked DENT specimens, is proposed.Īdvanced high-strength steels (AHSS) play a fundamental role in the development of modern lightweight automobiles. Based on the relation fracture toughness-local formability, a new AHSS classification mapping accounting for global formability and cracking resistance is proposed. The results reveal that fracture toughness cannot be estimated from any of the parameters derived from tensile tests and show the importance of microstructural features on crack propagation resistance. The specific essential work of fracture ( w e) is shown to be a suitable parameter to evaluate the local formability and fracture resistance of AHSS. Different fracture-related parameters, such as the true fracture strain (TFS), the true thickness strain (TTS), the fracture toughness at crack initiation ( w i e), the specific essential work of fracture ( w e), and the hole expansion ratio (HER), are assessed. The fracture resistance of different advanced high-strength steel (AHSS) sheets for automotive applications is investigated through conventional tensile tests, fracture toughness measurements, and hole expansion tests.
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