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.

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.

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.

Developing Uniaxial Tensile Test as an Alternate Method for Thermo Mechanical Process Evaluation

2011 ◽  
Vol 383-390 ◽  
pp. 5404-5408
Author(s):  
Dedi Priadi ◽  
Richard A. M. Napitupulu ◽  
Eddy S. Siradj
Keyword(s):  
Tensile Test ◽  
Plane Strain ◽  
Testing Machine ◽  
Forming Limit Diagram ◽  
Grain Structure ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Mechanical Process ◽  
Uniaxial Test

The alternate method for evaluating the thermo mechanical process has been developed. Small attention has been paid to the mechanism of plastic deformation especially plane strain analysis. Modified the specimen geometry and using uniaxial tensile test was done to view the process. Experimental results show that the forming limit diagram as one of the formability characteristic can be view the plane strain condition that present on the thermo mechanical process. The microstructure result shows that there is a similar grain structure between hot tensile test and hot rolling results as one of thermo mechanical process method. It was concluded that the uniaxial test using universal testing machine could be done to evaluate the thermo mechanical process.

Fracture Energy of Reactive Powder Concrete Based on Uniaxial Tensile Test

2011 ◽  
Vol 306-307 ◽  
pp. 519-522
Author(s):  
Hai Yan Yuan ◽  
Ming Zhe An ◽  
Fang Fang Jia ◽  
Zhi Gang Yan
Keyword(s):  
Tensile Test ◽  
Fracture Energy ◽  
Testing Machine ◽  
Strain Curve ◽  
Reactive Powder Concrete ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Stress Strain Curve ◽  
Concentration Problem ◽  
Reactive Powder

Based on uniaxial tensile test, the complete uniaxal tensile stress-strain curve of Reactive Powder Concrete (the steel fiber content by volume is Vf =1%, 2%) was obtained, and the fracture energy of RPC specimens with cross-section of 100mm by 100mm was calculated. The test was finished through Universal Testing Machine without any stiffness-strengthen devices. In order to solve the stress concentration problem, a self-designed uniaxial tensile test equipment was developed, and a dumbbell-shaped specimen was used in the test. The results indicate that the fracture energy of RPC increased as well as the increasing of Vf.

Anisotropic Plastic Behavior of TRIP 780 Steel Sheet in Hole Expansion Test

2012 ◽  
Vol 504-506 ◽  
pp. 89-94 ◽  
Author(s):  
Sansot Panich ◽  
Vitoon Uthaisangsuk ◽  
Surasak Suranuntchai ◽  
Suwat Jirathearanat
Keyword(s):  
Steel Sheet ◽  
Flow Behavior ◽  
Plastic Anisotropy ◽  
Yield Potential ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Biaxial Test ◽  
Hole Expansion ◽  
Expansion Test ◽  
Hole Expansion Test

Plastic behavior of advanced high strength steel sheet of grade TRIP780 (Transformation Induced Plasticity) was investigated using three different yield functions, namely, the von Mises’s isotropic, Hill’s anisotropic (Hill’48), and Barlat’s anisotropic (Yld2000-2d) criterion. Uniaxial tensile and balanced biaxial test were conducted for the examined steel in order to characterize flow behavior and plastic anisotropy in different stress states. Additionally, disk compression test was performed for obtaining the balanced r-value. According to the different yield criteria, yield stresses and r-values were calculated for different directions and then compared with experimental data. To verify the modeling accuracy, a hole expansion test was carried out experimentally and numerically by FE simulation. Stress-strain curve from the biaxial test was described using voce and swift hardening models. Punch load and stroke, final hole radius, and strain distribution on specimen surface along the hole circumference and the specimen diameter in rolling and transverse directions were determined and compared with the experimental results. It was found that the simulations applying Yld2000-2d yield function provided an acceptable agreement. Consequently, it is noted that the anisotropic yield potential significantly affects the accuracy of the predicted deformation behavior of sheet metal subjected to hole expanding load.

Modeling of Anisotropic Plastic Behavior of Advanced High Strength Steel Sheet TRIP 780

2011 ◽  
Vol 410 ◽  
pp. 232-235 ◽  
Author(s):  
Sansot Panich ◽  
Vitoon Uthaisangsuk ◽  
Surasak Suranuntchai ◽  
Suwat Jirathearanat
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
Plastic Anisotropy ◽  
High Strength ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Biaxial Test ◽  
Advanced High Strength Steel ◽  
Yield Criteria ◽  
Anisotropic Plastic

Anisotropic plastic behavior of advanced high strength steel sheet of grade TRIP780 (Transformation Induced Plasticity) was investigated using three different yield functions, namely, the von Mises’s isotropic, Hill’s anisotropic (Hill’48), and Barlat’s anisotropic (Yld2000-2d) criterion. Uniaxial tensile and balanced biaxial test were conducted for the examined steel in order to characterize flow behavior and plastic anisotropy for different stress states. Especially, disk compression test was performed for obtaining balanced r-value. All these data were used to determine the anisotropic coefficients. As a result, yield stresses and r-values for different directions were calculated according to these yield criteria. The results were compared with experimental data. To verify the modelling accuracy, tensile tests of various notched samples were carried out and stress-strain distributions in the critical area were characterized. By this manner, the effect of stress triaxiality due to different notched shapes on the strain localization calculated by the investigated yield criteria could be studied.

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

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