Factors influencing the forming limit diagram: Part I — The experimental determination of the forming limits of sheet steel

1980 ◽  
Vol 3 (3-4) ◽  
pp. 289-302 ◽  
Author(s):  
H.J. Kleemola ◽  
J.O. Kumpulainen
Keyword(s):  
Experimental Determination ◽  
Sheet Steel ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Forming Limits ◽  
Factors Influencing

scholarly journals Experimental Determination of Forming Limit Diagram and Springback Characteristics of AZ31B Mg Alloy Sheets at Elevated Temperatures

2008 ◽  
Vol 49 (5) ◽  
pp. 1112-1119 ◽  
Author(s):  
Hyung Jong Kim ◽  
Sun Chul Choi ◽  
Kyoung Taek Lee ◽  
Heon Young Kim
Keyword(s):  
Experimental Determination ◽  
Elevated Temperatures ◽  
Forming Limit Diagram ◽  
Mg Alloy ◽  
Forming Limit

Theorical and experimental determination of the forming limit diagram for the AISI 304 stainless steel

2006 ◽  
Vol 179 (1-3) ◽  
pp. 56-60 ◽  
Author(s):  
Haroldo Béria Campos ◽  
Marilena Carmen Butuc ◽  
José Joaquim Grácio ◽  
João E. Rocha ◽  
José Manuel Ferreira Duarte
Keyword(s):  
Stainless Steel ◽  
Experimental Determination ◽  
Forming Limit Diagram ◽  
304 Stainless Steel ◽  
Forming Limit ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304

An Innovative Procedure for the Experimental Determination of the Forming Limit Curves

2015 ◽  
pp. 11-16
Author(s):  
Dorel Banabic ◽  
Lucian Lazarescu ◽  
Dan-Sorin Comsa
Keyword(s):  
Experimental Determination ◽  
Forming Limit ◽  
Forming Limit Curves

Determination Of Formability Of Bimetallic Sheet Using Forming Limit Diagram

2019 ◽  
Vol 18 ◽  
pp. 2787-2795
Author(s):  
B.V.S. RAO
Keyword(s):  
Forming Limit Diagram ◽  
Forming Limit ◽  
Bimetallic Sheet

Influence of Different Pre-Stretching Modes on the Forming Limit Diagram of AA6014

2012 ◽  
Vol 504-506 ◽  
pp. 71-76 ◽  
Author(s):  
Alexandra Werber ◽  
Mathias Liewald ◽  
Winfried Nester ◽  
Martin Grünbaum ◽  
Klaus Wiegand ◽  
...  
Keyword(s):  
Plane Strain ◽  
Biaxial Loading ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Linear Strain ◽  
Forming Limits ◽  
Systematic Analysis ◽  
Measurement Systems ◽  
Non Linear ◽  
Strain Paths

In order to evaluate the formability of sheet materials forming limit diagrams (FLD) are recorded which represent the values of major and minor strain when necking occurs. FLDs are recorded based on the assumption that exclusively linear strain paths occur. In real forming parts, however, particularly in those with complex shapes, predominantly non-linear strain paths occur which reduce the accuracy of the failure prediction according to a conventional FLD. For this reason forming limits after loading with non-linear strain paths have to be investigated. In this contribution a systematic analysis of the forming limits of a conventional AA6014 alloy after loading with non-linear strain paths is presented. This material is pre-stretched in uniaxial, plane strain and biaxial direction up to several levels before performing Nakajima experiments in order to determine FLDs. During the pre-stretching process as well as during the Nakajima experiment the strain distribution can be measured online very precisely with the optical deformation measurement systems GOM Aramis or VIALUX. The gained curves are compared to the FLD of the as-received material. The results prove a significant influence of the pre-stretching condition on the forming limits of the used aluminum alloy. For a low pre-stretching in uniaxial as well as in biaxial direction the FLDs show a slightly reduced formability while after higher pre-stretching levels the forming limit can be improved such as for biaxial loading after uniaxial pre-stretching. The formability after pre-stretching in plane strain direction was changed. Also, a shift of the FLD depending on the direction of pre-stretching can be observed.

Forming limit analysis of Mg-2Zn-1.2Al-0.2Ca-0.2RE alloy sheet using ductile fracture models

2019 ◽  
Vol 29 (8) ◽  
pp. 1181-1198 ◽  
Author(s):  
Fei-Fan Li ◽  
Gang Fang ◽  
Ling-Yun Qian
Keyword(s):  
Magnesium Alloy ◽  
Ductile Fracture ◽  
Stress Triaxiality ◽  
Forming Limit Diagram ◽  
Alloy Sheet ◽  
Image Correlation ◽  
Forming Limit ◽  
Correlation Technique ◽  
Forming Limits ◽  
Fracture Models

This work was aimed to experimentally and theoretically investigate the formability of a new magnesium alloy sheet at room temperature. The fracture forming limit diagram was predicted by MMC3 and DF2014 models, where the non-linear strain path effect was taken into account by means of damage accumulation law. In order to obtain the instantaneous values of the stress triaxiality and the Lode parameter during the deformation process, strains tracked by digital image correlation technique were transformed into stresses based on the constitutive equations. The fracture forming limit diagram predicted by the fracture models was compared with the forming limits obtained by ball punch deformation tests. The prediction errors were evaluated by the accumulative damage values, which verified the advantages of ductile fracture models in predicting the forming limits of the magnesium alloy sheets.

Influence of Pre-Forming on the Forming Limit Diagram of Aluminum and Steel Sheets

2007 ◽  
Vol 344 ◽  
pp. 113-118 ◽  
Author(s):  
Massimo Tolazzi ◽  
Marion Merklein
Keyword(s):  
Dual Phase Steel ◽  
Process Analysis ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Linear Strain ◽  
Forming Limit Diagrams ◽  
Steel Sheets ◽  
Biaxial Stretching ◽  
Strain Paths

This paper presents a method for the experimental determination of forming limit diagrams under non linear strain paths. The method consists in pre-forming the sheets under two different strain conditions: uniaxial and biaxial, and then stretching the samples, cut out of the preformed sheets, using a Nakajima testing setup. The optical deformation measurement system used for the process analysis (ARAMIS, Company GOM) allows to record and to analyze the strain distribution very precisely with respect to both time and space. As a reference also the FLDs of the investigated grades (the deep drawing steel DC04, the dual phase steel DP450 and the aluminum alloy AA5754) in as-received conditions were determined. The results show as expected an influence of the pre-forming conditions on the forming limit of the materials, with an increased formability in the case of biaxial stretching after uniaxial pre-forming and a reduced formability for uniaxial load after biaxial stretching if compared to the case of linear strain paths. These effects can be observed for all the investigated materials and can be also described in terms of a shifting of the FLD, which is related to the art and magnitude of the pre-deformation.

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