The effect of strain rate and temperature on forming limit diagram for DKP-6112 and AZ31 materials

2020-01-01
Goksen, Seckin
Darendeliler, Haluk
© 2020 The Authors. Published by Elsevier Ltd.Forming limit diagrams (FLDs) are used in sheet metal operations widely for predicting blank fracture and forming characteristics of materials. There are three approaches for building forming limit diagrams which are the experimental, theoretical and numerical methods. Experimental method, which includes Nakazima formability test, is generally preferred for determining forming limit diagrams, although it requires complex experimental setup and effort. This study, firstly, compares the experimentally determined FLD results with the numerically obtained ones by using the constitutive models formed through the use of von Mises criteria with isotropic, kinematic and combined hardening models, and Hill48 yield criterion at quasi-static loading and room temperature conditions. The stress-strain relations are obtained by applying the Johnson-Cook phenomenological model for DKP-6112 and AZ31 materials. Then, the constitutive relation that gives closest results to experimental data is chosen to evaluate the effects of the variations of strain rate and temperature values on the FLDs for both materials. Nakazima tests, with 8 different blank specimens, are simulated by using a finite element software to present and compare the numerical forming limit diagrams. For determining the necking time in numerical FLDs maximum strain acceleration strain localization method is used. It is observed that forming limit diagram shifts downwards with strain rate increase and shifts upwards with temperature increase for both materials.

Suggestions

Multi objective optimization of water jet guided laser micro drilling on Inconel 718 using Taguchi Method
Subasi, Levent; Gökler, Mustafa İlhan; Yaman, Ulaş (2020-01-01)
© 2020 The Authors. Published by Elsevier B.V.Water jet guided laser overcomes the adverse effects of conventional laser cutting and drilling processes, such as heat-affected-zone, spatter, burr formation, etc. Pressurized water in this novel process provides focusing, cooling and cleaning on the cut region, eliminating undesired side effects of the laser. The process is nowadays used in energy and aerospace industries for drilling micro cooling holes on turbine blades made of super alloys. However, more re...
Transformation from SysML to RePast and Back
Çam, Sema; Görür, Bilge K.; Ledet, Joseph; Oğuztüzün, Mehmet Halit S.; Yilmaz, Levent (2020-01-01)
© 2020 The Authors. Published by Elsevier B.V.All rights reserved.Applying Model Driven Architecture (MDA) concepts and tools to Multi Agent Systems (MAS) is a topic of great interest in recent years. MDA intends to reduce computer code development effort via model transformations and makes complex systems available and more practical for research. In this work, we propose a model transformation process for a widely used agent-based modeling and simulation tool, RePast Simphony. We adopt SysML for the platf...
Prediction of yields and composition of char from fast pyrolysis of commercial lignocellulosic materials, organosolv fractionated and torrefied olive stones
Magalhães, Duarte; Gürel, Kaan; Matsakas, Leonidas; Christakopoulos, Paul; Pisano, Italo; Leahy, J.J.; Kazanç Özerinç, Feyza; Trubetskaya, Anna (Elsevier BV, 2021-04-01)
© 2020 The Author(s)This study investigated the fast pyrolysis behaviour of torrefied olive stones, fractionated olive stones and lignocellulosic commercial compounds. Olive stones were reacted in a continuous industrial torrefaction unit. The olive stones were also fractionated into their main components in an organosolv reactor at temperatures from 170 to 190 °C in both the presence and absence of an acidic catalyst. All samples were reacted in a wire mesh reactor at different temperatures (800–1150 °C) a...
Representing preferences by choquet integral: Guidelines to specify the capacity type
Dolgun, Leman Esra; Burnak, Nimetullah; Köksal, Gülser (Growing Science, 2020-06-01)
© 2020 by the authors; licensee Growing Science, Canada.This study considers representing decision maker preferences by Choquet integral in existence of interactions among criteria. Parameters of the Choquet integral are capacities which assign weights not only to criteria but also to each subset of criteria. This property provides Choquet integral with the ability of modeling some types of interactions. Different capacity types with different degrees of complexity have been defined in the literature. After...
The mechanical and electronic properties of spinel oxides VX2O4 (X = Mn and Fe) by first principle calculations
Ylldlz, Bugra; Erkişi, Aytaç; Sürücü, Gökhan (2019-11-25)
© 2019 Author(s).We have performed first-principles density functional theory calculations within generalized-gradient approximation to obtain the mechanical properties and the electronic behavior of Vanadium based Spinel Oxides VX2O4 (X=Mn and Fe) which conform Fm-3m space group with 225 space number and are promising good candidates for spintronic applications due to their half-metallic band gaps (Eg=1.71 eV for VFe2O4 and Eg = 0.53 eV for VMn2O4) in the plotted spin-polarized electronic band structure. A...
Citation Formats
S. Goksen and H. Darendeliler, “The effect of strain rate and temperature on forming limit diagram for DKP-6112 and AZ31 materials,” 2020, vol. 47, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56356.