Experimental Investigation of Key Process Parameters During Continuous-Bending-Under-Tension of AA6022-T4

2017 ◽  
Author(s):  
Edward M. Momanyi ◽  
Timothy J. Roemer ◽  
Brad L. Kinsey ◽  
Yannis P. Korkolis
Keyword(s):  
Experimental Investigation ◽  
Aluminum Alloys ◽  
Process Parameters ◽  
Tensile Tests ◽  
Load Cycle ◽  
Gauge Length ◽  
Uniaxial Tensile ◽  
Plastic Bending ◽  
Continuous Bending ◽  
Bending Under Tension

Continuous-Bending-Under-Tension (CBT) is an experimental technique that has been shown to increase elongation-to-fracture by over 100% in aluminum alloys and over 300% in steel as compared to uniaxial tensile tests [1]. This procedure is a modified form of a tensile test in which a specimen experiences 3 point plastic bending, induced by traversing 3 rollers back and forth over the gauge length, while simultaneously being pulled in tension. This process is able to delay the occurrence of necking in pure tension by suppressing the instability. Thus, significantly more elongation is achieved in the specimen prior to fracture. In this paper, an experimental investigation of key process parameters, i.e., bending depth and pulling speed, during CBT testing of AA6022-T4 is presented. The load cycle during a CBT test will also be discussed along with the strain induced throughout the gauge length.

Numerical Investigation of Residual Formability and Deformation Localization During Continuous-Bending-Under-Tension

2012 ◽  
Author(s):  
Chetan Nikhare ◽  
Brad L. Kinsey ◽  
Yannis Korkolis
Keyword(s):  
Numerical Simulations ◽  
Numerical Investigation ◽  
Sheet Metal ◽  
Past Research ◽  
Gauge Length ◽  
Tension Test ◽  
Deformation Localization ◽  
Percent Elongation ◽  
Continuous Bending ◽  
Bending Under Tension

A ubiquitous experiment to characterize the formability of sheet metal is the standard uniaxial tension test. Past research [1–3] has shown that if the material is repeatedly bent and unbent during this test (termed Continuous-Bending-under-Tension, or CBT), the percent elongation at failure increases significantly (e.g., from 22% to 290% for an AISI 1006 steel [1]). However, past experiments have been conducted with a fixed stroke of the CBT device, which limits the formability improvements. This phenomenon has also been empirically observed in industry; the failure strains of a sheet which is passed through a drawbead (i.e., that has been bent and unbent three times before entering the die) are higher than those of the original sheet. Thus, the residual formability of the material after a specified number of CBT passes is of interest, to determine if multiple drawbeads would be beneficial in the process. Also of interest is the localization of the deformation during the process as this will provide a better physical understanding of the improved formability observed. In this paper, numerical simulations are presented to assess these effects. Results show that the formability during CBT is dictated by the uniaxial response of the material until the standard elongation at failure is exceeded. This limit can be exceeded by the CBT process. However, failure then occurs as soon as the CBT process is terminated. Also, the deformation is more uniformly distributed over the entire gauge length during the CBT process which leads to the increased elongations observed.

scholarly journals Experimental Study on Mechanical Properties of Aluminum Alloys under Uniaxial Tensile Tests

2017 ◽  
Vol 8 (4) ◽  
pp. 662 ◽  
Author(s):  
Olfa Daghfas ◽  
Amna Znaidi ◽  
Ahmed Ben Mohamed ◽  
Rachid Nasri
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Aluminum Alloys ◽  
Tensile Tests ◽  
Uniaxial Tensile

scholarly journals Measurement and Analysis of Heterogeneous Strain Fields in Uniaxial Tensile Tests for Boron Steel Under Hot Stamping Conditions

2020 ◽  
Vol 60 (9) ◽  
pp. 1289-1300
Author(s):  
R. Zhang ◽  
Z. Shao ◽  
J. Lin ◽  
T. A. Dean
Keyword(s):  
Temperature Gradient ◽  
Hot Stamping ◽  
Tensile Tests ◽  
Gauge Length ◽  
Image Correlation ◽  
Effect Of Temperature ◽  
Uniaxial Tensile ◽  
Boron Steel ◽  
Strain Fields ◽  
Dog Bone

Abstract Background A significant amount of uniaxial tensile tests has been carried out using Gleeble systems to investigate the viscoplastic deformation of boron steel (22MnB5) under hot stamping conditions. However, due to heat loss through the end clamps, a temperature gradient in the reduced parallel section of dog-bone shaped specimens is inevitable. Objective In the work reported in this paper, the effect of temperature gradient on measured outcomes is examined. Methods Uniaxial tensile tests on 1.5 mm thick boron steel specimens are carried out, under hot stamping conditions and strain fields are quantified using the digital image correlation (DIC) technique. The effect of gauge length on the properties of boron steel, as calculated from observed test results, is determined. Results Compared with the test at room temperature, a bell-shaped strain distribution occurs within the gauge length even before the appearance of the maximum load. Also, average strain within the gauge length, especially in the later stages, changes with gauge length within the investigated range, and thus, different engineering stress-strain curves and fracture strains are determined. In addition, normalized strain rate is significantly dependent on gauge length, which results in over 16% difference among the computed flow stresses by using a unified constitutive model. Conclusions The characterized properties of the material are dependent on gauge length and thus, a testing standard for measuring thermal-mechanical data of materials by using a Gleeble need to be defined.

Effects of Temperature and Strain Rate on Commercial Aluminum Alloy AA5083

2014 ◽  
Vol 660 ◽  
pp. 332-336 ◽  
Author(s):  
Mohd Khir Mohd Nor ◽  
Ibrahim Mohamad Suhaimi
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behaviour ◽  
Model Development ◽  
Tensile Tests ◽  
Gauge Length ◽  
Uniaxial Tensile ◽  
Important Conclusion ◽  
Commercial Aluminum Alloy

Superplastic forming, SPF is a special metalworking process that allows sheets of metal alloys such as aluminum to be stretched to lengths over ten times. Nowdays, only a few aluminium alloys can meet the specific requirement of SPF manufacturing process and not much data available to represent their mechanical behaviour. In order to deal with this issue, this research project is conducted to investigate the characteristics of commercial aluminum alloy, AA5083 when tested at different strain rates and temperatures. These parameters play a crucial roles in the design and manufacturing processes of military, automotive and aerospace structures. Equally, the effects must be considered in the constitutive model development to accurately capture the deformation behaviour of such materials. The specimens were prepared according to 12.5mm gauge length standard. The Uniaxial Tensile Tests were carried out at various strain rate from 4.167 x10-1s-1to 4.167 x10-5s-1over a wide temperature range from ambient to 95°C. The experimental data shows that increasing strain rate increases flow stress, while increasing temperature decrease flow stress. This is leads to important conclusion that material AA5083 exhibits strain rate and temperature sensitivite, and suit with the SPF operating condition.

Effects of Temperature on Deep Drawing of Sheet Metals

1983 ◽  
Vol 105 (2) ◽  
pp. 119-127 ◽  
Author(s):  
J. O. Kumpulainen ◽  
A. J. Ranta-Eskola ◽  
R. H. O. Rintamaa
Keyword(s):  
Deep Drawing ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Drawing Ratio ◽  
Aisi 304 ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Strip Drawing ◽  
Effects Of Temperature ◽  
Bending Under Tension

The influence of temperature on the flow stress and the uniform strain of steel, brass, aluminium and AISI 304 and 316 type stainless steels is determined by using uniaxial tensile tests. Sliding and stretching friction coefficients at several surface temperatures are measured for various sheets and lubricants using a bending under tension type strip drawing test. The validity of the results is verified by deep drawing experiments. The influence of temperature difference between the punch nose region and the flange on the drawing and fracture loads and on the limiting drawing ratio is determined.

Design of a Continuous-Bending-Under-Tension Machine and Initial Experiments on Al-6022-T4

2015 ◽  
Author(s):  
Timothy J. Roemer ◽  
Brad L. Kinsey ◽  
Yannis P. Korkolis
Keyword(s):  
Plastic Deformation ◽  
Tensile Test ◽  
Experimental Technique ◽  
Tension Test ◽  
Gage Length ◽  
Friction Test ◽  
Plastic Bending ◽  
Three Point Bending ◽  
Continuous Bending ◽  
Bending Under Tension

An experimental technique called Continuous-Bending-Under-Tension (CBT) can produce elongations over two times that of a standard tensile test by preventing the necking instability from occurring. This is achieved by superposing plastic bending on tension along the gage length of the material using three rollers. The specimen is kept under tension as the rollers apply the three point bending and cyclically transverse along the gage length. This localizes the plastic deformation by subjecting the specimen to bending-under-tension. Details on the design of the unique CBT machine and some preliminary results for the CBT research being conducted are presented here. These results include CBT tests where the roller depth was varied to demonstrate the increased elongation compared to the traditional tension test, CBT repeatability, and a modified friction test using the CBT machine.

scholarly journals The Development of a Gracilis and Quadriceps Tendons Calibration Device for Uniaxial Tensile Tests

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 364
Author(s):  
Ivan Grgić ◽  
Mirko Karakašić ◽  
Željko Ivandić ◽  
Tanja Jurčević Jurčević Lulić
Keyword(s):  
Fused Deposition Modeling ◽  
Soft Tissues ◽  
Complex Geometry ◽  
Tensile Tests ◽  
Gauge Length ◽  
Uniaxial Tensile ◽  
Specimen Preparation ◽  
Tissue Properties ◽  
Fused Deposition ◽  
Calibration Device

To determine the biomechanical properties of the distal tendon of the gracilis muscle and the upper third of the quadriceps femoris muscle used for reconstruction of the medial patellofemoral ligament (MPFL), it is necessary to develop a calibration device for specimen preparation for uniaxial tensile tests. The need to develop this device also stems from the fact that there is currently no suitable regulatory or accurate protocol by which soft tissues such as tendons should be tested. In recent studies, various methods have been used to prepare test specimens, such as the use of different ratios of gauge lengths, different gripping techniques, etc., with the aim of obtaining measurable and comparable biomechanical tissue properties. Since tendons, as anisotropic materials, have viscoelastic properties, the guideline for manufacturing calibrator devices was the ISO 527-1:1993 standard, used for testing polymers, since they also have viscoelastic behaviour. The functionality of a calibrator device was investigated by preparing gracilis and quadriceps tendon samples. Fused deposition modeling (FDM) technology was used for the manufacturing of parts with complex geometry. The proposed calibrator could operate in two positions, horizontal and vertical. The maximum gauge length to be achieved was 60 mm, with the maximum tendon length of 120 mm. The average preparation time was 3 min per tendon. It was experimentally proven that it is possible to use a calibrator to prepare tendons for tensile tests. This research can help in the further development of soft tissue testing devices and also in the establishment of standards and exact protocols for their testing.

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