Investigation of Anisotropy Effect on the Material Properties Obtained from Biaxial Tests

2020 ◽  
Vol 856 ◽  
pp. 128-134
Author(s):  
Chalida Udomraksasakul ◽  
Thanasan Intarakumthornchai ◽  
Yingyot Aue-u-Lan
Keyword(s):  
Flow Stress ◽  
Tensile Test ◽  
Mechanical Test ◽  
Rolling Direction ◽  
Uniaxial Tensile ◽  
Bulge Test ◽  
Uniaxial Tensile Test ◽  
Biaxial Test ◽  
Anisotropy Effect ◽  
Biaxial Tests

Hydraulic bulge test or biaxial test is a well-known mechanical test used to determine a flow stress of material because of the large level of effective strains and not interfered by the necking unlike in uniaxial tensile test. However, the flow stress obtained is influenced by the anisotropy effect. That flow stress needs to be corrected by the anisotropic values (r-values) obtained from the uniaxial tensile test which limited by the necking. Therefore, to obtain the accurate flow stress the r-values should be determined directly from the biaxial test. The elliptical tests with ratio of 2 (the ratio between major and minor axis) at different sheet orientations (0๐ and 90๐ from the rolling direction) and the equibiaxial test were proposed. In this research, the effect of the sheet orientations upon the flow stress (K and n values) under biaxial tests was investigated by experiment and equation of material grade SPCD with the thickness of 0.8mm. The results showed that the flow stress without correcting r-values gave more variations than those with correcting one with the r-values obtained from the uniaxial test. Therefore, the r-values used to correct the flow stress under biaxial test should be directly determined from the biaxial test.

Determination of Flow Curve Using Bulge Test and Calibration of Damage for Ito-Goya Models

2013 ◽  
Vol 554-557 ◽  
pp. 182-189 ◽  
Author(s):  
Bruno Martins ◽  
Abel D. Santos ◽  
Pedro Teixeira ◽  
K. Ito ◽  
N. Mori
Keyword(s):  
Tensile Test ◽  
Damage Model ◽  
Strain Curve ◽  
Uniaxial Tensile ◽  
Bulge Test ◽  
Uniaxial Tensile Test ◽  
Damage Prediction ◽  
Damage Models ◽  
Material Information

The standard uniaxial tensile test is the widely accepted method to obtain relevant properties of mechanical characterization of sheet metal materials. However the range of strain obtained from tensile test is limited. The bulge test is an alternative to obtain ranges of deformation, higher than tensile test, thus permitting a better characterization for material behaviour. This paper presents a sensitivity analysis for some influencing variables used in bulge measurements, thus giving some guidelines for the evaluation of the stress-strain curve from experimental results using a developed experimental mechanical system. Additionally, using bulge test up to fracture shall give material information regarding damage, which in turn may be used to evaluate and calibrate damage models. A methodology is presented to be used for evaluation and calibration of Ito-Goya damage model of damage prediction.

Further Investigation of the Hydrostatic Bulge Test in a Plasticity Laboratory

2009 ◽  
Vol 37 (2) ◽  
pp. 159-174
Author(s):  
O. Ifedi ◽  
Q. M. Li ◽  
Y. B. Lu
Keyword(s):  
Tensile Test ◽  
Effective Stress ◽  
Strain Curve ◽  
Plasticity Theory ◽  
Loading Path ◽  
Uniaxial Tensile ◽  
Bulge Test ◽  
Uniaxial Tensile Test ◽  
Stress Strain Curve ◽  
Stress Strain

In plasticity theory, the effective stress–strain curve of a metal is independent of the loading path. The simplest loading path to obtain the effective stress–strain curve is a uniaxial tensile test. In order to demonstrate in a plasticity laboratory that the stress–strain curve is independent of the loading path, the hydrostatic bulge test has been used to provide a balanced biaxial tensile stress state. In our plasticity laboratory we compared several different theories for the hydrostatic bulge test for the determination of the effective stress–strain curve for two representative metals, brass and aluminium alloy. Finite element analysis (FEA) was performed based on the uniaxial tension test data. It was shown that the effective stress–strain curve obtained from the biaxial tensile test (hydrostatic bulge test) had a good correlation with that obtained in the uniaxial tensile test and agreed well with the analytical and FEA results. This paper may be used to support an experimental and numerical laboratory in teaching the concepts of effective stress and strain in plasticity theory.

Fundamental Investigation for Tensile Test Using Conical Cupping Die

2014 ◽  
Vol 622-623 ◽  
pp. 292-299 ◽  
Author(s):  
Tomoyuki Ota ◽  
Takashi Iizuka
Keyword(s):  
Tensile Test ◽  
Testing Machine ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Bulge Test ◽  
Uniaxial Tensile Test ◽  
Biaxial Tensile ◽  
Specimen Shape ◽  
Specimen Edge

A number of researches have conducted in order to evaluate the ductile fracture occurrence by using forming limit diagram. However, specimen shape and testing machine for obtaining forming limit diagram of sheet metal have some problems. The problem about specimen shape is occurring at the specimen edge. In uniaxial tensile test, the specimen edge may cause a defused neck in width direction and may have influence on fracture occurrence. In biaxial tensile test by using a cruciform specimen, a uniform biaxial deformation is not obtained because uniaxial tensile stress occurs at the specimen edge. Tensile test by using a specimen which does not have such edges should carry out, for example, in bulge test and multi-axial tube expansion test, specimens without edge are used. However, these methods need special machines. Therefore, new biaxial tensile testing method is required. By this method, materials deform depending on biaxial strain state by using popular pressing machines.

scholarly journals Calibration of Material Parameters of Anisotropic Yield Criterion with Conventional Tests and Biaxial Test

2013 ◽  
Vol 554-557 ◽  
pp. 2111-2117 ◽  
Author(s):  
Shun Ying Zhang ◽  
Lionel Leotoing ◽  
Dominique Guines ◽  
Sandrine Thuillier
Keyword(s):  
Yield Criterion ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Yield Function ◽  
Uniaxial Tensile ◽  
Bulge Test ◽  
Biaxial Test ◽  
Yield Model ◽  
Conventional Tests ◽  
Strain Paths

Bron and Besson yield criterion has been used to investigate the plastic anisotropic behavior of an aluminum alloy AA5086. The parameters of this anisotropic yield model have been identified by two different methods: a classical one, considering several homogeneous conventional experiments and an exploratory one, with only biaxial test. In this paper, the parameter identification with conventional experiments has been carried out with uniaxial tensile tests and simple shear tests in different orientations to the rolling direction and with a hydraulic bulge test. For comparison’s sake, Hill’s 48 yield function has also been calibrated analytically from uniaxial tensile tests. Numerical simulation for the cross biaxial test has been carried out with the anisotropic parameters identified from the conventional tests. From this simulation, the principle strains along a specified path in the gauge area of the cruciform specimen have been evaluated. A good agreement is observed between experimental and numerical values of principal strains for a large range of strain paths.

Instrumentation and Control of a Bulge Test on a Superplastic Pb-Sn Alloy

2012 ◽  
Vol 735 ◽  
pp. 224-231
Author(s):  
Erick Petta Marinho ◽  
Alberto Sakata ◽  
Erika Fernanda Prados ◽  
Gilmar Ferreira Batalha
Keyword(s):  
Strain Rate ◽  
Superplastic Forming ◽  
Uniaxial Tensile ◽  
Bulge Test ◽  
Uniaxial Tensile Test ◽  
Biaxial Test ◽  
Biaxial Testing ◽  
Forming Process ◽  
Set Up ◽  
And Control

Superplasticity is characterized by high elongations under a high strain rate sensibility, and it’s variation with strain rate, temperature and grain size. This parameter is often obtained from uniaxial tensile test. However, superplastic deformation is a biaxial process; hence there is a need to develop a way to get this parameter in a biaxial test. This work aims to set up the instrumentation to record and control a biaxial superplastic forming in a Pb-Sn alloy. The control system project has been divided into tracking variables: strain and pressure. The instrumentation is able to predict the breaking point at the beginning of the superplastic forming process from biaxial testing.

scholarly journals Calibration of Advanced Yield Criteria Using Uniaxial and Heterogeneous Tensile Test Data

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 542
Author(s):  
Andraž Maček ◽  
Bojan Starman ◽  
Nikolaj Mole ◽  
Miroslav Halilovič
Keyword(s):  
Tensile Test ◽  
Strain Field ◽  
Plastic Anisotropy ◽  
Testing Machine ◽  
Biaxial Stress ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Biaxial Test ◽  
Test Results ◽  
Full Field

Conventionally, plastic anisotropy is calibrated by using standard uniaxial tensile and biaxial test results. Alternatively, heterogeneous strain field specimens in combination with full-field measurements can be used for this purpose. As reported by the literature, such an approach reduces the number of required tests enormously, but it is challenging to obtain reliable results. This paper presents an alternative methodology, which represents a compromise between the conventional and heterogeneous strain field calibration technique. The idea of the method is to use simple tests, which can be conducted on the uniaxial testing machine, and to avoid the use of advanced measuring equipment. The procedure is accomplished by conducting standard tensile tests, which are simple and reliable, and by a novel heterogeneous strain field tensile test, to calibrate the biaxial stress state. Moreover, only two of the parameters required for full characterisation need to be inversely identified from the test response; the other parameters are directly determined from the uniaxial tensile test results. This way, a dimension of optimization space is reduced substantially, which increases the robustness and effectiveness of the optimization algorithm.

scholarly journals Coupled Thermomechanical Response Measurement of Deformation of Nickel-Based Superalloys Using Full-Field Digital Image Correlation and Infrared Thermography

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2163
Author(s):  
Krzysztof Żaba ◽  
Tomasz Trzepieciński ◽  
Sandra Puchlerska ◽  
Piotr Noga ◽  
Maciej Balcerzak
Keyword(s):  
Surface Temperature ◽  
Strain Rate ◽  
Rolling Direction ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Response Measurement ◽  
Sheet Rolling ◽  
Inconel Alloys ◽  
The Relationship

The paper is devoted to highlighting the potential application of the quantitative imaging technique through results associated with work hardening, strain rate and heat generated during elastic and plastic deformation. The aim of the research presented in this article is to determine the relationship between deformation in the uniaxial tensile test of samples made of 1-mm-thick nickel-based superalloys and their change in temperature during deformation. The relationship between yield stress and the Taylor–Quinney coefficient and their change with the strain rate were determined. The research material was 1-mm-thick sheets of three grades of Inconel alloys: 625 HX and 718. The Aramis (GOM GmbH, a company of the ZEISS Group) measurement system and high-sensitivity infrared thermal imaging camera were used for the tests. The uniaxial tensile tests were carried out at three different strain rates. A clear tendency to increase the sample temperature with an increase in the strain rate was observed. This conclusion applies to all materials and directions of sample cutting investigated with respect to the sheet-rolling direction. An almost linear correlation was found between the percent strain and the value of the maximum surface temperature of the specimens. The method used is helpful in assessing the extent of homogeneity of the strain and the material effort during its deformation based on the measurement of the surface temperature.

Design and development of aluminum alloy 6061-T6 pressure vessel liner for aerospace applications: A technical brief

2021 ◽  
pp. 146442072110651
Author(s):  
R Pramod ◽  
N Siva Shanmugam ◽  
C K Krishnadasan ◽  
G Radhakrishnan ◽  
Manu Thomas
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Weld Metal ◽  
Tensile Test ◽  
Pressure Vessel ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Aluminum Alloy 6061 ◽  
Custom Made ◽  
Alloy 6061

This work mainly focuses on designing a novel aluminum alloy 6061-T6 pressure vessel liner intended for use in launch vehicles. Fabrication of custom-made welding fixtures for the assembly of liner parts, namely two hemispherical domes and end boss, is illustrated. The parts of the liner are joined using the cold metal transfer welding process, and the welding trials are performed to arrive at an optimized parametric range. The metallurgical characterization of weld joint reveals the existence of dendritic structures (equiaxed and columnar). Microhardness of base and weld metal was 70 and 65 HV, respectively. The tensile strength of base and weld metal was 290 and 197 MPa, respectively, yielding a joint efficiency of 68%. Finite-element analysis of a uniaxial tensile test was performed to predict the tensile strength and location of the fracture in base and weld metal. The experimental and predicted tensile test results were found to be in good agreement.

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