Determination of Flow Curves under Equibiaxial Stress Conditions

2012 ◽  
Vol 504-506 ◽  
pp. 53-58 ◽  
Author(s):  
J. Mulder ◽  
Henk Vegter ◽  
Jin Jin Ha ◽  
A.H. van den Boogaard
Keyword(s):  
Low Carbon Steel ◽  
Temperature Correction ◽  
Stress Conditions ◽  
Biaxial Stress ◽  
Bulge Test ◽  
Low Carbon ◽  
Flow Curves ◽  
Hydraulic Bulge ◽  
The Individual

Three experimental methods have been used to establish flow curves for a low carbon steel under biaxial stress conditions: the hydraulic bulge test, the stack compression test and the biaxial tensile test. The individual tests are discussed and the results for a DC06 IF steel grade compared. Initially the results appear to be different but after compensation, including strain rate and temperature correction, the true hardening curves are coinciding.

Behavior of Steel Under Biaxial Stress as Determined by Tests on Tubes

1948 ◽  
Vol 15 (3) ◽  
pp. 201-215
Author(s):  
H. E. Davis ◽  
E. R. Parker
Keyword(s):  
Low Temperature ◽  
Low Carbon Steel ◽  
Stress Conditions ◽  
Biaxial Stress ◽  
Low Carbon ◽  
Plastic Range ◽  
Strain Behavior ◽  
Simple Tension ◽  
Two Temperatures ◽  
Reasonable Prediction

Abstract The experimental work is described and results presented for tests on twelve 5¼-in-diam thin-walled tubes of low-carbon steel subjected to various conditions of biaxial stress. These experiments composed the “pilot” series of tests in a larger investigation on the behavior of ship-plate steel under multiaxial stress conditions. The ductility of the metal under various biaxial stress conditions and at two temperatures, 70 F and −138F, is reported. The evidence indicates that the metal is reasonably ductile, even at the low temperature, provided it is subjected only to a state of plane stress. If a state of triaxial stress is induced by restraint or by discontinuities in the material, the ductility may be greatly reduced at the low temperature. Evidence is presented to indicate that fracture may occur either by shear or by cleavage, depending upon the stress and temperature conditions. In a majority of cases, reasonable prediction of the stress-strain behavior of the metal in the plastic range can be made for various biaxial stress conditions from the data of the simple tension test, by use of the modified octahedral-shear concept.

Determination of Mechanical Properties for the Hydroforming of Magnesium Sheets at Elevated Temperature

2005 ◽  
Vol 6-8 ◽  
pp. 779-786 ◽  
Author(s):  
J. Hecht ◽  
S. Pinto ◽  
Manfred Geiger
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Tensile Test ◽  
Flow Curve ◽  
Elevated Temperatures ◽  
Biaxial Stress ◽  
Bulge Test ◽  
Hydraulic Bulge Test ◽  
Hydraulic Bulge

Thanks to the low weight, magnesium alloys feature high specific strength and stiffness properties. Thus they prove to be promising materials for todays ambitious automotive light weight construction efforts. Due to their comparative low formability at room temperature the process of magnesium sheet hydroforming can be improved at temperatures higher than 200 °C by the activation of additional sliding planes. This paper illustrates the determination of mechanical properties for the hydroforming of magnesium sheets at elevated temperature. In particular the mechanical behavior at elevated temperature was investigated by means of the tensile test and of the hydraulic bulge test. For the determination of the strains an optical measurement system was introduced into the experimental set-up. The exact knowledge of the strain condition in the area of diffuse necking enabled the determination of the flow curve in the tensile test also beyond the uniform elongation. The influence of temperature and strain rate was analyzed as well as the influence of uni- and biaxial stress state on the flow curve. Using circular and elliptic dies with different aspect ratio the hydraulic bulge test served to determinate the forming limit curves at three different elevated temperatures.

Single Particle Interaction Properties: Investigations on the Coefficient of Restitution and Coefficient of Friction

2012 ◽  
Author(s):  
Martin C. Marinack ◽  
Patrick S. M. Dougherty ◽  
C. Fred Higgs
Keyword(s):  
Coefficient Of Friction ◽  
Particle Interaction ◽  
Low Carbon Steel ◽  
Granular Flows ◽  
Coefficient Of Restitution ◽  
Natural Phenomena ◽  
Low Carbon ◽  
Solids Processing ◽  
Particle Level ◽  
The Individual

Understanding granular flows has always been important for predicting natural phenomena such as rockslides and soil erosion, as well as industrial processes such as coal-based fossil fuel systems and solids processing. As such, it becomes important to understand granular flows from both a classical granular flow and tribological perspective. Inherently important in the study of granular flows is the study of the individual particle level interactions, which define the global behavior of the flow. The current work examines both the coefficient of restitution (COR) and coefficient of friction (COF) for various material combinations. COR and tribological experiments are performed on various sphere and plate (disk) materials, such as low carbon steel, tungsten carbide (WC), and NITINOL 60.

A Comparative Study on Hydraulic Bulge Testing and Analysis Methods

2008 ◽  
Author(s):  
Eren Billur ◽  
Muammer Koc¸
Keyword(s):  
Flow Stress ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Material Behavior ◽  
Biaxial Stress ◽  
Dome Height ◽  
Bulge Test ◽  
Analysis Methods ◽  
Bulge Testing ◽  
Hydraulic Bulge

Hydraulic bulge testing is a material characterization method used as an alternative to tensile testing with the premise of accurately representing the material behavior to higher strain levels (∼70% as appeared to ∼30% in tensile test) in a biaxial stress mode. However, there are some major assumptions (such as continuous hemispherical bulge shape, thinnest point at apex) in hydraulic bulge analyses that lead to uncertainties in the resulting flow stress curves. In this paper, the effect of these assumptions on the accuracy and reliability of flow stress curves is investigated. The goal of this study is to determine the most accurate method for analyzing the data obtained from the bulge testing when continuous and in-line thickness measurement techniques are not available. Specifically, in this study the stress-strain relationships of two different materials (SS201 and Al5754) are obtained based on hydraulic bulge test data using various analysis methods for bulge radius and thickness predictions (e.g., Hill’s, Chakrabarty’s, Panknin’s theories, etc.). The flow stress curves are calculated using pressure and dome height measurements and compared to the actual 3-D strain measurement from a stereo optical and non-contact measurement system ARAMIS. In addition, the flow stress curves obtained from stepwise experiments are compared with the ones from above methods. Our findings indicate that Enikeev’s approach for thickness prediction and Panknin’s approach for bulge radius calculation result in the best agreement with both stepwise experiment results and 3D optical measurement results.

CHARACTERIZATION OF FLOW CURVES FOR ULTRA-THIN STEEL SHEETS WITH THE IN-PLANE TORSION TEST

2021 ◽  
pp. 1-25
Author(s):  
Fabian Stiebert ◽  
Heinrich Traphöner ◽  
Rickmer Meya ◽  
A. Erman Tekkaya
Keyword(s):  
Sheet Thickness ◽  
High Strength ◽  
Torsion Test ◽  
New Method ◽  
Bulge Test ◽  
Thin Sheets ◽  
Flow Curves ◽  
Steel Sheets

Abstract The in-plane torsion test is a shear test that has already been successfully used to determine flow curves up to high strains for thin sheets with thicknesses between 0.5 mm and 3.0 mm. In the same way as with other shear tests, the formation of wrinkles is a major challenge in determining flow curves with the in-plane torsion test, especially when testing ultra-thin sheets with a thickness between 0.1 mm and 0.5 mm. A new method for suppressing wrinkling is introduced, in which the formation of wrinkles is avoided by arranging and gluing single sheets to multi-layered specimens. The influence of the used adhesive on the determination of flow curves is negligible. The proposed method is used to identify flow curves for two materials, the high strength steel TH620 and the soft steel TS230, used in the packaging industry. The Materials are tested in sheet thicknesses between 0.17 mm and 0.6 mm. The determined equivalent plastic strains for the TH620 with a sheet thickness of 0.20 mm, could be increased from 0.38 (bulge-test) to over 0.8 with the new method by using four-layered specimens.

scholarly journals The impact of exploitation and environmental factors on the degradation of steel road safety equipment

2018 ◽  
Vol 231 ◽  
pp. 01012
Author(s):  
Joanna Kobus ◽  
Lech Kwiatkowski ◽  
Rafał Lutze
Keyword(s):  
Road Safety ◽  
Zinc Coating ◽  
Low Carbon Steel ◽  
Environmental Parameters ◽  
Galvanized Steel ◽  
Traffic Intensity ◽  
Low Carbon ◽  
Zinc Corrosion ◽  
The Impact

The work is aimed at determining the corrosivity of atmosphere in the vicinity of roads, taking into account the characteristics of local emission sources, including traffic intensity of vehicles along with climatic and exploitation factors. Determination of the corrosivity of atmosphere was carried out according to the procedures described in PN EN ISO standards. Samples for testing were made of low carbon steel DC05, zinc and hot dip galvanized steel. Samples were assembled at 19 sites in the close vicinity of roads and highways near the measurement points of vehicle traffic intensity. The mass loss of exposed samples was the basis for determination the atmosphere corrosivity at each of 19 test sites. Regarding steel, the corrosivity category of C4 was observed at 8/19 sites. Corrosion losses outside roads are 2-4 times lower and ranged within the categories of C2 and C3. Zinc corrosion losses classified to category C4 occurred at 2/19 stations. In the remaining ones they corresponded to category C3. In areas outside of roads, zinc corrosion losses are about 20-100% lower (C2). The first attempts to model the dependence of operating and environmental parameters on zinc and zinc coating corrosion losses indicate significant correlation between zinc and zinc coating corrosion losses as a function.

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