Method of Obtaining Forming Limit Diagram for Electro-hydraulic Stamping

2021 ◽  
pp. 167-175
Author(s):  
Viacheslav S. Mamutov ◽  
Alexander V. Mamutov ◽  
Xenia S. Arsenteva ◽  
Vladimir V. Blazhevich
Keyword(s):  
Forming Limit Diagram ◽  
Forming Limit

Optimization of Tube Hydroforming Process Using Probabilistic Constraints on Failure Modes

2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami
Keyword(s):  
Failure Modes ◽  
High Reliability ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Plastic Instability ◽  
Probabilistic Constraints ◽  
Forming Limit ◽  
Reliability Based Design ◽  
Hydroforming Process

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.

Formability Analysis of AA6061 Sheet in T6 Condition

2015 ◽  
Vol 766-767 ◽  
pp. 416-421
Author(s):  
S. Vijayananth ◽  
V. Jayaseelan ◽  
G. Shivasubbramanian
Keyword(s):  
Experimental Method ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Ansys Software ◽  
Limit Curve ◽  
High Corrosion Resistance ◽  
Forming Limit Curve ◽  
Drawing Test ◽  
Deep Drawing Test ◽  
Alloy 6061

Formability of a material is defined as its ability to deform into desired shape without being fracture. There will always be a need for formability tests, a larger number of tests have been used in an effort to measure the formability of sheet materials. Aluminium Alloy 6061 is a magnesium and silicon alloy of aluminium. It is also called as marine material as it has high corrosion resistance to seawater. In this paper Formability test of AA6061 sheet is done by Forming Limit Diagram (FLD) Analysis. FLD or Forming Limit Curve (FLC) for the forming processes of AA6061 sheets is obtained by Experimental method and FEM. Experimental method involves Deep drawing test of the sheet and ANSYS software is used for FEM.

Optimization of Sheet Metal Process Parameters of a Shield Case Piece Using Computer Simulation

2006 ◽  
Vol 510-511 ◽  
pp. 330-333
Author(s):  
M.C. Curiel ◽  
Ho Sung Aum ◽  
Joaquín Lira-Olivares
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Physical Processes ◽  
Forming Process ◽  
Element Analysis ◽  
One Step ◽  
Range Of Values ◽  
Principal Strains

Numerical simulations based on Finite Element Analysis (FEA) are widely used to predict and evaluate the forming parameters before performing the physical processes. In the sheet metal industry, there are basically two types of FE programs: the inverse (one-step) programs and the incremental programs. In the present paper, the forming process of the shield case piece (LTA260W1-L05) was optimized by performing simulations with both types of software. The main analyzed parameter was the blankholding force while the rest of the parameters were kept constant. The criteria used to determine the optimum value was based on the Forming Limit Diagram (FLD), fracture and wrinkling of the material, thickness distribution, and the principal strains obtained. It was found that the holding force during the forming process deeply affects the results, and a range of values was established in which the process is assumed to give a good quality piece.

Discussion of the Worst Case Scenario of FLD0

2000 ◽  
Author(s):  
Naji Arwashan
Keyword(s):  
Simple Formula ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Vertical Position ◽  
Engineering Practice ◽  
Case Scenario ◽  
Worst Case ◽  
Grid Analysis ◽  
Worst Case Scenario ◽  
Minimum Value

Abstract The Forming Limit Diagram is used in circle grid analysis to check the safety of a formed panel. The shape of the Forming Limit Diagram for steel is always the same, it is only the vertical position of the diagram that varies depending on the value of FLD0. For steel, FLD0 is widely accepted to be dependent on the thickness and n value which are both inherently indeterministic, and can exhibit variations, small or large, depending on the manufacturing process. To account for this variability in determining the safety of a formed panel, the engineering practice in many companies is to use a minimum value for FLD0 called Worst Case Scenario, because it is calculated using minimum values for both t and n. This paper presents a different and better approach to calculate the minimum value of FLD0. The approach is based on probabilistic concepts, and allows the calculation of a minimum value for FLD0 that is related to a certain probability of occurrence. The derivation technique used in the paper is borrowed from Reliability Analysis and tailored to solve our problem. The derivation leads to a simple formula that can be easily used. The minimum value of FLD0 calculated according to the paper is more accurate than the Worst Case Scenario, and provides better cost saving since it is always greater than the Worst Case Scenario value.

Loading Path Dependence of Forming Limit Diagram of a TRIP800 Steel

2011 ◽  
Vol 4 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Kyoo Sil Choi ◽  
Ayoub Soulami ◽  
Wenning Liu ◽  
Xin Sun ◽  
Moe Khaleel
Keyword(s):  
Path Dependence ◽  
Forming Limit Diagram ◽  
Loading Path ◽  
Forming Limit

scholarly journals Forming limit diagram prediction of 6061 aluminum by GTN damage model

2018 ◽  
Vol 19 (2) ◽  
pp. 202 ◽  
Author(s):  
Rasoul Safdarian
Keyword(s):  
Damage Model ◽  
Forming Limit Diagram ◽  
Numerical Results ◽  
Experimental Results ◽  
Correct Selection ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Gtn Model ◽  
Gtn Damage Model

Forming limit diagram (FLD) is one of the formability criteria which is a plot of major strain versus minor strain. In the present study, Gurson-Tvergaard-Needleman (GTN) model is used for FLD prediction of aluminum alloy 6061. Whereas correct selection of GTN parameters’ is effective in the accuracy of this model, anti-inference method and numerical simulation of the uniaxial tensile test is used for identification of GTN parameters. Proper parameters of GTN model is imported to the finite element analysis of Nakazima test for FLD prediction. Whereas FLD is dependent on forming history and strain path, forming limit stress diagram (FLSD) based on the GTN damage model is also used for forming limit prediction in the numerical method. Numerical results for FLD, FLSD and punch’s load-displacement are compared with experimental results. Results show that there is a good agreement between the numerical and experimental results. The main drawback of numerical results for prediction of the right-hand side of FLD which was concluded in other researchers’ studies was solved in the present study by using GTN damage model.

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