Determination of Damage Criterion Using a Hybrid Analysis for Advanced High Strength Steel

Abstract

Advanced High Strength (AHS) steels have been increasingly applied in the automotive industries due to their distinguished mechanical properties. Microstructures of these steels play an important role and are designed by constituent phases with distinct characteristics. AHS steels exhibit sophisticated damage mechanisms that complicate the prediction of material formability. In this work, Ductile Crack Initiation Locus (DCIL) was developed for describing failure behavior of dual phase steel sheet. A hybrid experimental and numerical analysis was used to determine the DCIL. Tensile tests of various sample geometries were experimentally carried out and crack initiation occurred during forming was identified by the Direct Current Potential Drop (DCPD) method. Then, FE simulations of the corresponding tests were performed to evaluate local stress triaxialities and equivalent plastic strains of the critical area. The damage curves for both crack initiation and localized necking were obtained. Additionally, the von Mises, Hill48 and Yld2000-2d yield criterion were defined in the calculations in order to examine effect of yield model on the resulted curves. To verify applicability of the damage curves, Nakazima test of uniaxial sample was taken into account.

Assessing the Feasibility of Cold Forming of Automotive Parts from Quenched and Partitioned Martensitic Stainless Steels

“…The strength model establishes the material's limits for failure under the given simulated conditions. In particular, a similar approach has already been used in the previous work by Panich et al, [ 19 ] where a yield model is coupled with the forming limit diagram (FLD) and forming limit stress diagram (FLSD) fracture criteria to assess the formability of steel sheets under stamping processes, having as an outcome a successful prediction when comparing the data with those extracted from real experiments.…”

Damage Curve Determination of Dual-Phase Steel Based on Micromechanical Damage by Using Numerical Analysis and Experimental Investigation

“…The seven different geometry [14] of the tensile test are performed to predict the dependence of the fracture ductility in positive stress triaxiality. At high stress triaxiality (0.3-0.6) are identified by using tensile specimen which is uniaxial, Radius, U-, C-and V-notch specimen.…”

“…In case of formability of a sheet material, due to complex damage condition of dual-phase sheets, the initiation of micro crack based on the ductile crack initiation locus (DCIL) have to be considered to characterize the formability for ductile sheet steels. Consequently, in this study, GTN model parameters determination, aimed to develop the damage curve for crack initiation of dual phase DP780 [14] by numerical analysis based on GTN model failure criteria, the results of damage curve shows the crack initiation which is verified by Nakazima test of uniaxial sample and others yield criteria for considering the effect of the results…”

Fully coupled numerical analysis of high frequency induction heating and warm sheet metal forming

“…Two blank materials were compared: a cold rolled steel sheet (SPCE) with a thickness of 1.0 mm, and an AA5182‐O sheet with a thickness of 1.15 mm. Table summarizes the mechanical properties required for sheet metal forming simulation . ABAQUS Standards ® was used for the simulation of the deep drawing processes.…”