TECHNICAL ARTICLE—PEER-REVIEWED Ductile Fracture Study of Stainless Steel AISI 304L Thin Sheets Using the EWF Method and Cohesive Zone Modeling R. Bensaada . M. Almansba . R. Ferhoum . Z. Sidhoum Submitted: 19 March 2018 / in revised form: 27 May 2018 Ó ASM International 2018 Abstract The purpose of this study is to model the ductile fracture phenomenon using experimental and numerical methods. The stainless steel AISI 304L thin sheets are studied including two thicknesses (0.8 and 1.5 mm). A mechanical characterization is firstly done in order to obtain the main mechanical properties useful for the numerical modeling. In order to determine the essential work of fracture (EWF), DENT specimens are used involving the two thicknesses. The results obtained in terms of EWF for the two thicknesses are close; we find that the essential work of fracture can be considered as an intrinsic criterion for thin sheets. A cohesive zone model- ing (CZM) is used in the present study; the model is represented by a traction–separation law (TS). The cohe- sive elements are implemented in the finite element model, and the material parameters of the model are determined by the mechanical and fracture characterizations. A satisfac- tory reproduction of the experimental tests is obtained. A good correlation is also obtained between the essential work of fracture determined experimentally and the work of separation used as cohesive zone model parameter. Keywords Ductile fracture  Cohesive zone model  DENT  Stainless steel  Traction–separation Introduction Stainless steels are of great importance in the modern industry. Despite the emergence of composite materials as result of their good resistance/weight ratio, these steels are difficult to replace in many sectors such as nuclear, naval and automotive industry. These important areas require the knowledge of the properties of the materials used and their limitations. Analysis and prediction of fracture are also of paramount importance for equipment used at high pressure and subject to large deformations, etc. In the last decades, considerable efforts were provided within the scientific community to propose powerful methods and models that can predict the ruin of materials. It was recognized by several researchers that the global fracture mechanics cri- teria ‘K and J’ are strongly dependent on the geometric and shape parameters of specimens and defects. Among the consequences of this dependence, we find the variation of the constraint effect in the vicinity of the crack front; this dependence plays a key role in the variation of fracture toughness and the crack propagation. The essential work of fracture concept was introduced by Cotterell and Reddel [1] as a method to obtain the fracture toughness of steel thin sheets. This method assumes that the fracture process zone is surrounded by a large plastic area. The work carried out in this area has a dimensional and geometric depen- dence; it must be separated from the total work in order to obtain the essential work carried out in the fracture process zone. The idea of separating the two works emanated from Broberg [2]. The essential work of fracture can be con- sidered as the inverse approach of the classical fracture mechanics by characterizing the fracture toughness not at the crack initiation but at the total separation of ligament. This method considers that the total energy ðW f Þ required R. Bensaada  M. Almansba Experimental and Numerical Modeling of Materials and Structures Laboratory, Mouloud MAMMERI University of Tizi- Ouzou, BP 17 RP, 15000 Hasnaoua II, Algeria R. Ferhoum (&)  Z. Sidhoum Preparation, Characterization of Materials and Modeling Laboratory, Mouloud MAMMERI University of Tizi-Ouzou, BP 17 RP, 15000 Hasnaoua II, Algeria e-mail: ferhoum@yahoo.fr 123 J Fail. Anal. and Preven. https://doi.org/10.1007/s11668-018-0507-4