metals Article Fracture Toughness Analysis of Automotive-Grade Dual-Phase Steel Using Essential Work of Fracture (EWF) Method Sunil Kumar M R 1,* , Eva Schmidova 1 , Pavel Konopík 2, Daniel Melzer 2, Fatih Bozkurt 3 and Neelakantha V Londe 4 1 Faculty of Transport Engineering, University of Pardubice, 53210 Pardubice, Czech Republic;
[email protected] 2 Mechanical Testing and Thermophysical Measurement, COMTES FHT a.s., 33441 Dobˇrany, Czech Republic;
[email protected] (P.K.);
[email protected] (D.M.) 3 Vocational School of Transportation, Eskisehir Technical University, 26140 Eskisehir, Turkey;
[email protected] 4 Department of Mechanical Engineering, Mangalore Institute of Technology & Engineering, Moodabidre 574225, India;
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[email protected]; Tel.: +420-777-95-5826 Received: 2 July 2020; Accepted: 27 July 2020; Published: 29 July 2020 Abstract: Fracture toughness determination of dual-phase DP450 steel using the essential work of fracture (EWF) methodology is the major focus of this research work. The EWF method is used for the determination of fracture toughness of thin sheets in a plane stress dominant condition. The EWF method is discussed in detail with the help of DP450 steel experimental results. Double edge notched tension (DENT) specimens with fatigue pre-crack and without fatigue crack (notched) have been e used for testing. Specific essential work of fracture (we), crack tip opening displacement (δc) and crack tip opening angle ( e) parameters were used for the comparative analysis. High-intensity laser beam cutting technology was used for the preparation of notches. Fracture toughness values of fatigue pre-cracked and notched samples were compared.