Effect of Frictional Conditions in Deep Drawing on Formability

2021 ◽  
Vol 904 ◽  
pp. 26-30
Author(s):  
Xia Zhu ◽  
Hiromichi Toyota ◽  
Hironori Hagio ◽  
Shigekiyo Ishikawa ◽  
Takahiro Akutagawa
Keyword(s):  
Stress Concentration ◽  
Friction Coefficient ◽  
Simulation Analysis ◽  
Plate Thickness ◽  
Mechanical Damage ◽  
Reduction Ratio ◽  
Thickness Reduction ◽  
Forming Limit ◽  
Forming Process ◽  
Strain Behavior

This study investigated the stress and strain behavior caused in the forming process via simulation analysis using the finite element method, for suppressing punch shoulder and head plate thickness reduction die shoulder stress concentration by controlling the friction conditions. The following findings were obtained: The thickness of the blank head and punch shoulder decreased with the forming process. Due to the increase in the coefficient of friction with the punch side, the plate thickness reduction ratio decreases, and is the lowest when it is close to non-lubrication; Stress concentration occurs at the die shoulder with forming processing. With the increase in the friction coefficient value, forming limit parameter (FLP) increases slightly, but as it does not reach the limit value of 1, the forming process can be safely performed without mechanical damage; When the formability is comprehensively evaluated using the plate thickness reduction ratio and FLP, the friction coefficient μ = 0.4 to 0.5 is reasonable.

Sheet Metal Forming Limit Prediction with Maximum Thickness Reduction Ratio

2011 ◽  
Vol 314-316 ◽  
pp. 999-1004
Author(s):  
Jie Shi Chen ◽  
Jun Chen
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Strain Path ◽  
Reduction Ratio ◽  
Thickness Reduction ◽  
Forming Limit ◽  
Forming Process ◽  
Maximum Thickness

Maximum thickness reduction ratio is used to predict sheet metal forming limit in the numerical simulation of forming process. The maximum thickness reduction ratio under different stain path is not a constant for the same material. The effect of strain path and strain hardening exponent on forming limit is considered. The relationship between the maximum thickness reduction ratio that the material can obtained and the strain path between tensile to equi-biaxial is established. The parameter in the criterion can be determined by tensile experiment combined with numerical simulation of the same forming process. Then the limit strains under other linear strain paths between tensile to equi-biaxial can be determined by the criterion combined with numerical simulation of corresponding forming process. Forming limits of three kinds of sheet metals are predicted with the modified maximum thickness reduction ratio criterion. Good agreement is achieved between the predicted data and the experimental data.

Investigation on Friction Coefficient Considering Al-Si Coating Layer Fracture of Boron Sheets in Hot and Cold Deep Drawing

2020 ◽  
Vol 846 ◽  
pp. 117-121
Author(s):  
Min Sik Lee ◽  
Jun Park ◽  
J.S.Suresh Babu ◽  
Chung Gil Kang
Keyword(s):  
Friction Coefficient ◽  
Deep Drawing ◽  
Deformation Behavior ◽  
Coating Layer ◽  
Surface Condition ◽  
Forming Limit ◽  
Boron Steel ◽  
Drawing Process ◽  
Forming Process ◽  
Deep Drawing Process

In this paper, hot and cold deep drawing processes are determined with direct deep drawing process and indirect deep drawing process. To predict the friction coefficient, the finite-element method, which can predict deformation behavior until the fracture of a blank sheet, was proposed using the forming limit diagram (FLD) curve. The effect of fracturing of the coating layer on the friction coefficient during the hot and cold deep drawing processes was investigated. The deformation behavior of the coating layer of the boron steel sheet that affects the friction coefficient in the hot and cold deep drawing processes was also proposed. A forming method that can control the surface condition of the formed product is further proposed by explaining the fracture of the coating due to the forming process.

scholarly journals Statistical and Experimental Study of the Stretching Force for 6061 Aluminum Alloy Using post stretching and pre strecting processes

2019 ◽  
Vol 27 (2) ◽  
pp. 74-87
Author(s):  
Sadiq Jaffar Aziz ◽  
Mohammed Dahkil Abbas
Keyword(s):  
Experimental Tests ◽  
Reduction Ratio ◽  
Thickness Reduction ◽  
Aluminum Sheet ◽  
Stretch Forming ◽  
Forming Process ◽  
Variable Parameters ◽  
Statistic Study ◽  
Important Input ◽  
Stretching Process

An experiment and a statistic study was performed considering the effect of two important input parameters (stretching force and stretching speed) on the stretching behaviour of 6061-0 aluminum sheet in terms of thickness reduction ratio in two types of stretch forming process (post stretching and pre stretching). Experimental tests were carried out using a die with V-shape to stretch the sheet at two selected levels of stretching force and stretching speed and according to the design matrices established by the Design of Experiment (DOE) software (Version 10). Two models with two variable parameters, i.e. stretching force and speed  were built by using the response surface methodology (RSM) technique for the two cases of stretching (post and pre stretching), then checked statistically for adequacy purpose by analysis of variance (ANOVA) analysis, and appeared good with 95 % confidence level. It was found that using the post stretch forming process generally gives a lower thickness reduction ratio than that for pre stretching process. This explains the advantages of using post-stretching process to stretch the 6061-0 aluminum sheet alloy.

Numerical Simulation and Verification of Multi-Operation Sheet Forming Process for Stamping Parts of Spiral Step Surface

2011 ◽  
Vol 189-193 ◽  
pp. 2911-2916
Author(s):  
Ling Sun ◽  
Jian Wei Xing ◽  
Wu Hua Cheng
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Low Cost ◽  
Sheet Thickness ◽  
Forming Limit ◽  
Drawing Process ◽  
Forming Process ◽  
Actual Measurement ◽  
Blank Holder ◽  
Product Thickness

On the basis of in-depth simulation analysis of stress and strain, thickness and forming limit changes in the property sphere during the drawing process for the stamping part of the spiral step surface, combined with the comprehensive simulation analysis of flanging, punching and other operations for the parts, it is concluded that the most obvious non-uniform changes of sheet thickness occur in the drawing process and then in the flanging process. The possibility and the distribution of tension fracture in ironing and wrinkles in thickening has been predicted and the production feasibility of low-cost drawing process without the blank holder and multi-operation forming process for stamping parts of spiral step surface. The validity of multi-operation numerical simulation results has been verified by the actual measurement of finished product rate and product thickness in trial production.

Research on Structure and Lightweight of Automobile Seats

2014 ◽  
Vol 608-609 ◽  
pp. 51-55
Author(s):  
Na Lu
Keyword(s):  
Structural Optimization ◽  
Optimization Design ◽  
Simulation Analysis ◽  
Size Structure ◽  
Plate Thickness ◽  
Utilization Rate ◽  
Original Structure ◽  
State Variables ◽  
Forming Process ◽  
Seat Frame

This paper starts from the design of seat frame made of lightweight, structural optimization and forming process to analyze the car seat design of lightweight. The paper analyze new aluminum alloy seat using finite element simulation analysis and are the analysis of the structural optimization design based on the results. On this basis, in order to reduce the weight of the seat frame, built design variables model with components of plate thickness, taking stiffness and the first torsion frequency of seat frame as state variables under different conditions, taking total mass of seat frame lightweight optimization goal to optimize its parameters of size structure. The seat frame not only meets the strength requirements, but also improves the utilization rate of materials, compared with the original structure; the quality is reduced by 9.6% and get better lightweight.

scholarly journals Stress Concentration Factors for Welded Plate T-Joints Subjected to Tensile, Bending and Shearing Loads

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 546
Author(s):  
Krzysztof L. Molski ◽  
Piotr Tarasiuk
Keyword(s):  
Stress Concentration ◽  
Plate Thickness ◽  
Percentage Error ◽  
Geometrical Parameters ◽  
T Joints ◽  
Loading Mode ◽  
Weld Toe ◽  
Concentration Factors ◽  
Parametric Expression ◽  
Stress Concentration Factors

The paper deals with the problem of stress concentration at the weld toe of a plate T-joint subjected to axial, bending, and shearing loading modes. Theoretical stress concentration factors were obtained from numerical simulations using the finite element method for several thousand geometrical cases, where five of the most important geometrical parameters of the joint were considered to be independent variables. For each loading mode—axial, bending, and shearing—highly accurate closed form parametric expression has been derived with a maximum percentage error lower than 2% with respect to the numerical values. Validity of each approximating formula covers the range of dimensional proportions of welded plate T-joints used in engineering applications. Two limiting cases are also included in the solutions—when the weld toe radius tends to zero and the main plate thickness becomes infinite.

scholarly journals Formability study and metallurgical properties analysis of FSWed AA 6061 blank by the SPIF process

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Payam Tayebi ◽  
Ali Fazli ◽  
Parviz Asadi ◽  
Mahdi Soltanpour
Keyword(s):  
Base Metal ◽  
Strain Distribution ◽  
Thickness Distribution ◽  
Experimental Studies ◽  
Welding Process ◽  
Forming Limit ◽  
Forming Process ◽  
Friction Stir ◽  
Numerical Process ◽  
Tailor Welded Blank

AbstractIn this study, in order to obtain the maximum possible formability in tailor-welded blank AA6061 sheets connected by the friction stir welding (FSW) procedure, the incremental sheet forming process has been utilized. The results are presented both numerically and experimentally. To obtain the forming limit angle, the base and FSWed sheets were formed in different angles with conical geometry, and ultimately, the forming limit angle for the base metal and FSWed sheet is estimated to be 60° and 57.5°, respectively. To explore the effects of welding and forming procedures on AA6061 sheets, experimental studies such as mechanical properties, microstructure and fracture analysis are carried out on the samples. Also, the thickness distribution of the samples is studied to investigate the effect of the welding process on the thickness distribution. Then, the numerical process was simulated by the ABAQUS commercial software to study the causes of the FSWed samples failure through analyzing the thickness distribution parameter, and major and minor strains and the strain distribution. Causes of failure in FSWed samples include increased minor strain, strain distribution and thickness distribution in welded areas, especially in the proximity of the base metal area.

Magnesium Sheet Metal Forming Considering its Specific Yield Behavior

2005 ◽  
Vol 6-8 ◽  
pp. 771-778 ◽  
Author(s):  
M. Redecker ◽  
Karl Roll ◽  
S. Häussinger
Keyword(s):  
Sheet Metal ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Specific Yield ◽  
Forming Limit ◽  
Forming Process ◽  
Local Flow ◽  
Yield Behavior ◽  
Magnesium Sheet ◽  
Testing Procedures

In recent years very strong efforts have been undertaken to build light weight structures of car bodies in the automotive industry. Structural technologies like Space Frame, tailored blanks and relief-embossed panels are well-known and already in use. Beside that there is a large assortment of design materials with low density or high strength. Magnesium alloys are lighter by approximately 34 percent than aluminum alloys and are considered to be the lightest metallic design material. However forming processes of magnesium sheet metal are difficult due to its complex plasticity behavior. Strain rate sensitivity, asymmetric and softening yield behavior of magnesium are leading to a complex description of the forming process. Asymmetric yield behavior means different yield stress depending on tensile or compressive loading. It is well-known that elevated temperatures around 200°C improve the local flow behavior of magnesium. Experiments show that in this way the forming limit curves can be considerably increased. So far the simulation of the forming process including temperature, strain rates and plastic asymmetry is not state-of-the-art. Moreover, neither reliable material data nor standardized testing procedures are available. According to the great attractiveness of magnesium sheet metal parts there is a serious need for a reliable modeling of the virtual process chain including the specification of required mechanical properties. An existing series geometry which already can be made of magnesium at elevated temperatures is calculated using the finite element method. The results clarify the failings of standard calculation methods and show potentials of its improvement.

Determination of Stress Concentration Around an Oblique Hole by a Finite-Element Technique

1983 ◽  
Vol 105 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Hua-Ping Li ◽  
F. Ellyin
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Maximum Stress ◽  
Plate Thickness ◽  
Two Dimensional ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Parametric Studies ◽  
Element Technique

A plate weakened by an oblique penetration of a circular cylindrical hole has been investigated. The stress concentration around the hole is determined by a finite-element method. The results are compared with experimental data and other analytical works. Parametric studies of effects of angle of inclination, plate thickness, and width are performed. The maximum stress concentration factor (SCF) obtained from the finite-element analysis is higher than experimental results, and this deviation increases with the increase of angle of skewness. The major reason for this difference is attributed to the shear-action between layers parallel to the plate surface which cannot be directly included in the two-dimensional elements. An empirical formula is derived which accounts for the shear-action and renders the finite-element predictions in line with experimentally observed data.

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.

Sign in / Sign up

Export Citation Format

Share Document