Damage Analysis of Third-Generation Advanced High-Strength Steel Based on the Gurson–Tvergaard–Needleman (GTN) Model

Rafael O Santos,Gabriela Vincze,Luciano P Moreira,Marilena C Butuc,António B Pereira

doi:10.3390/met12020214

Abstract

The third generation of advanced high-strength steels (AHSS) brought attention to the steel and automotive industries due to its good compromise between formability and production costs. This work evaluated a third-generation AHSS (USS CR980XG3TM) through microstructural and X-ray diffraction (XRD) analyses, uniaxial tensile and plane-strain tension testing, and numerical simulations. The damage behavior of this steel is described with the Gurson–Tvergaard–Needleman (GTN) model using an identification procedure based on the uniaxial tensile and initial microvoids data. The microstructure of the CR980XG3TM steel is composed of ferrite, martensite–austenite islands, and retained austenite with a volume fraction of 12.2%. The global formability of the CR980XG3TM steel, namely the product of the uniaxial tensile strength and total elongation values, is 24.3 GPa%. The Lankford coefficient shows a weak initial plastic anisotropy of the CR980XG3TM steel with the in-plane anisotropy close to zero (−0.079) and the normal anisotropy close to unity (0.917). The identified GTN parameters for the CR980XG3TM steel provided a good forecast for the limit strains defined according to ISO 12004-2 standard from the uniaxial tensile and plane-strain tension data.

Highlights

IntroductionIn addition to concerns about CO2 emissions, the high fossil fuel prices harm the global economy
Climate changes are becoming more and more of a central topic of global discussions
Several advanced high-strength steels (AHSS) steel grades can be applied in the vehicle design, each strategically placed in the Body-in-White (BIW) to increase the crashworthiness performance

Summary

Introduction

In addition to concerns about CO2 emissions, the high fossil fuel prices harm the global economy. In response to the European Commission proposal, the European Automobile Manufacturers Association (ACEA) advocates a realistic target to reduce 20% of CO2 emissions [3]. In this context, the advanced high-strength steels (AHSS) have gained considerable importance in the automotive industry. The advanced high-strength steels (AHSS) have gained considerable importance in the automotive industry This steel class has been developed to satisfy the requirements of vehicle performance and weight optimization. The excellent compromise between uniaxial tensile strength and elongation allows manufacturing of the BIW components with reduced thickness, producing lighter vehicles resulting in fuel economy and reducing greenhouse gas emissions

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Discussion

Conclusion