Open AccessEvolution of a forming limit curve for non-linear strain paths induced on advanced high-strength sheet steel with its proven applicability to a complex deep-drawing process
Author(s) -
Komkamol Chongbunwatana,
Sansot Panich,
Korkiat Laokor
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/967/1/012036
Subject(s) - nonlinear system , structural engineering , materials science , tension (geology) , deep drawing , fracture (geology) , displacement (psychology) , stamping , yield (engineering) , path (computing) , plane stress , limit (mathematics) , composite material , finite element method , mathematical analysis , mathematics , ultimate tensile strength , computer science , engineering , physics , metallurgy , psychology , quantum mechanics , psychotherapist , programming language
In this work, nonlinear forming limit curves were developed through a systematic combination of both experimental and numerical tools. FLCs derived from both intact and pre-stretched DP440 high-strength steel (HSS) sheet were involved. First of all, prepared sheet specimens were, in compliance with the Marciniak test procedure, in-plane pre-stretched in either of the following three directions, uniaxial tension, plane strain and biaxial, at varying strain levels. Afterwards, each distinguishingly pre-strained specimen was post-strained until fracture following the Nakajima test guideline. The so-called displacement function could be determined out of these experimental data. An individual nonlinear IFU-FLCs was approximated with the help of the base linear FLC, the formulated displacement function and a unique simulated strain path collectively gathered from the local fracture zone. Two yield models, Hill’48 and Yld2000- 2d, were tried during strain-path calculations to observe how different yield models would alter the paths and thus developed nonlinear FLCs. From the study, notable variation was detected. In the end, validity of such nonlinear FLCs were proven through a complex-shaped industrial stamping part. The IFU-FLC noticeably-better defined forming limits of parts experiencing nonlinear strain paths than the conventional one.