The Optimization of Continuous Indentation Technique Parameters

2002 ◽  
Author(s):  
Eun-chae Jeon ◽  
Dongil Kwon ◽  
Joo-Seung Park
Keyword(s):  
Tensile Properties ◽  
Indentation Depth ◽  
Analysis Procedure ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Signal To Noise ◽  
Nondestructive Technique ◽  
Indentation Technique ◽  
Experimental Parameters ◽  
Continuous Indentation

Continuous indentation technique has been widely studied because of its various merits, such as simple experiments, short experiment time and nondestructive technique. It is proved that the technique can produce tensile properties from the load-depth curves without optical observation by many researches. When the experiment is performed, it is, however, very difficult to determine the values of various experimental parameters that affect derived tensile properties by inserted in numerical analysis procedure. In this study, the effects of the parameters were studied using Taguchi method which is a kind of design of experiment (DOE). The ratio of indentation depth to indenter radius, the indenter radius, the number of unloads and the unloading ratio were selected as the main parameters. The changes of derived tensile properties by the main parameters were analyzed by calculating signal-to-noise (SN) ratio. Finally, the optimum values of each parameter were determined. The tensile properties evaluated with the optimum values showed much better agreement to those from uniaxial tensile test.

Statistical Analysis of Experimental Parameters in Continuous Indentation Tests Using Taguchi Method

2003 ◽  
Vol 125 (4) ◽  
pp. 406-411 ◽  
Author(s):  
Eun-chae Jeon ◽  
Joo-Seung Park ◽  
Dongil Kwon
Keyword(s):  
Taguchi Method ◽  
Tensile Properties ◽  
Indentation Depth ◽  
Signal To Noise Ratio ◽  
Indentation Test ◽  
Indentation Load ◽  
Optimum Parameters ◽  
Experimental Parameters ◽  
Indentation Tests ◽  
Continuous Indentation

The continuous indentation test, which applies an indentation load to a material and records the indentation depth, yields indentation tensile properties whose accuracy can vary depending on such experimental parameters as number of unloadings, unloading ratio, maximum depth ratio and indenter radius. The Taguchi method was used to quantify their effects and to determine their optimum values. Using signal-to-noise ratio calculated from the error in the indentation tensile properties, the criterions and the optimum values for the experimental parameters were presented. The indentation tensile properties evaluated with the optimum parameters were in better agreement with the tensile properties.

Application of Instrumented Indentation Technique for Small Scale Testing

2007 ◽  
Author(s):  
Kug-Hwan Kim ◽  
Kyung-Woo Lee ◽  
Ju-Young Kim ◽  
Dongil Kwon ◽  
Kwang-Ho Kim
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Tensile Properties ◽  
Pressure Vessel ◽  
Uniaxial Tensile ◽  
Small Scale ◽  
Uniaxial Tensile Test ◽  
Instrumented Indentation ◽  
Indentation Technique

Instrumented indentation technique (IIT) is a novel tool to estimate mechanical properties such as tensile properties, residual stress and fracture toughness by analyzing indentation load-depth curve measured during loading-unloading of indentation. It can be applied directly in small-scale and localized sections of pressure vessel and pipeline since the preparation of specimen is very easy and the experimental procedure is feasible and nondestructive. We present the principles developed for measuring mechanical properties using IIT; the tensile properties by defining the representative stress and strain underneath a spherical indenter, the residual stress near the weldments using the stress-insensitive contact hardness model, and the fracture toughness of ductile metal based on critical indentation energy model. The experimental results from IIT were verified by comparing the results from the conventional methods such as uniaxial tensile test for tensile properties, mechanical saw-cutting and hole-drilling methods for residual stress, and CTOD test for fracture toughness. In particular, the applications of IIT in small scale materials and localized sections of the pressure vessel and pipeline in-use and in-fields are presented.

A Method for Estimating Uncertainty of Indentation Tensile Properties in Instrumented Indentation Test

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Eun-chae Jeon ◽  
Joo-Seung Park ◽  
Doo-Sun Choi ◽  
Kug-Hwan Kim ◽  
Dongil Kwon
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Tensile Properties ◽  
Indentation Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Instrumented Indentation ◽  
Estimation Model ◽  
Instrumented Indentation Test

The instrumented indentation test, which measures indentation tensile properties, has attracted interest recently because this test can replace uniaxial tensile test. An international standard for instrumented indentation test has been recently legislated. However, the uncertainty of the indentation tensile properties has never been estimated. The indentation tensile properties cannot be obtained directly from experimental raw data as can the Brinell hardness, which makes estimation of the uncertainty difficult. The simplifying uncertainty estimation model for the indentation tensile properties proposed here overcomes this problem. Though the influence quantities are generally defined by experimental variances when estimating uncertainty, here they are obtained by calculation from indentation load-depth curves. This model was verified by round-robin test with several institutions. The average uncertainties were estimated as 18.9% and 9.8% for the indentation yield strength and indentation tensile strength, respectively. The values were independent of the materials’ mechanical properties but varied with environmental conditions such as experimental instruments and operators. The uncertainties for the indentation yield and tensile strengths were greater than those for the uniaxial tensile test. These larger uncertainties were caused by measuring local properties in the instrumented indentation test. The two tests had the same tendency to have smaller uncertainties for tensile strength than yield strength. These results suggest that the simplified model can be used to estimate the uncertainty in indentation tensile properties.

Effect of Pulse Current on Mechanical Behavior of High Temperature Titanium Alloy Ti55

2021 ◽  
Vol 1035 ◽  
pp. 25-31
Author(s):  
Hai Feng Wan ◽  
Ai Jun Xu ◽  
Yun Long Huang ◽  
Ze Jun Tang
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Tensile Properties ◽  
Pulse Current ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Electrical Parameters ◽  
Dislocation Movement ◽  
High Pulse ◽  
Material Forming

The effects of pulse current on the tensile properties of high temperature titanium alloy Ti55 were investigated by pulse current assisted uniaxial tensile test under different electrical parameters. It was found that with the increase of peak current and pulse width, the tensile properties of Ti55 are significantly improved. At the same time, the pulsation effect of current on the mechanical properties of Ti55 was investigated. The results show that the tensile displacement of low pulsation group was higher, while the elongation of high pulsation group was higher. In order to explore the mechanism of pulsation effect of current, EBSD was adopted. The results indicated that high pulse current can significantly promote the dislocation movement and recrystallization. In addition, some macrozones was found in low pulsation group, which indicated that high pulsation current was more suitable for material forming than low pulsation current.

Evaluation of Mechanical and Fracture Characteristics Using Instrumented Indentation Technique

2007 ◽  
Vol 539-543 ◽  
pp. 2210-2215
Author(s):  
Jung Suk Lee ◽  
Kwang Ho Kim ◽  
Jae Hwan Han ◽  
Dong Il Kwon
Keyword(s):  
Fracture Toughness ◽  
Residual Stress ◽  
Material Characterization ◽  
Damage Mechanics ◽  
Evaluation Method ◽  
Flow Property ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Instrumented Indentation ◽  
Indentation Technique

The material characterization on the weak points of the structural systems is essential to evaluate safety accurately. However, general material characterization methods such as uniaxial tensile test and CTOD (crack tip opening displacement) test are destructive, therefore, it cannot be applied to the system in use. To overcome this problem, the material characterization using instrumented indentation technique was developed. However, current researches on instrumented indentation technique focus on the hardness measurement. The evaluation of flow property, residual stress and fracture toughness using instrumented indentation technique is not sufficiently performed. In this paper, we introduce the evaluation method of the flow property, the residual stress near the weldment and the fracture toughness developed from damage mechanics. The algorithm of flow property evaluation, the residual stress evaluation model and the fracture toughness model by using indentation were verified comparing with the experimental results.

Quasi-Static Tensile Properties and Damage Mechanism of Three-Dimensional Angle-Interlock Woven Composites

2012 ◽  
Vol 182-183 ◽  
pp. 148-152
Author(s):  
Kun Luan ◽  
Fa Zhang ◽  
Li Wei Wu
Keyword(s):  
Tensile Properties ◽  
Composite Structures ◽  
Three Dimensional ◽  
Test System ◽  
Tensile Failure ◽  
Woven Composites ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Absorption Mechanism ◽  
Dog Bone

The uniaxial tensile properties of three-dimensional angle-interlock woven composites (3DAWCs) under quasi-static loading were investigated in this paper. The samples were manufactured into dog-bone shape and tested on Material Test System 810.23. The strain-stress curves in warp direction indicating the Young’s moduli, maximum stress and maximum strain are achieved from the uniaxial tensile test. The effects of microstructure and damage morphology of 3DAWC under quasi-static tension are discussed. Furthermore, we will focus on the energy absorption mechanism from the view of tensile failure mode. The material parameters of 3DAWC in warp direction can be evaluated for developing quantitative approach to design polymer matrix composite structures.

Ball Indentation Studies on the Effect of Nitrogen on the Tensile Properties of 316LN SS

2015 ◽  
Vol 34 (8) ◽  
Author(s):  
M. D. Mathew ◽  
J. Ganesh Kumar ◽  
V. Ganesan ◽  
K. Laha
Keyword(s):  
Nitrogen Content ◽  
Tensile Properties ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Test Results ◽  
Alloy Development ◽  
High Temperature Mechanical Properties ◽  
Ball Indentation ◽  
316Ln Ss ◽  
Type 316L

AbstractType 316L(N) stainless steel (SS) containing 0.02–0.03 wt% carbon and 0.06–0.08 wt% nitrogen is used as the major structural material for the components of fast reactors. Research is underway to improve the high-temperature mechanical properties of 316LN SS by increasing the nitrogen content in the steel above the level of 0.08 wt%. In this investigation, ball indentation (BI) technique was used to evaluate the effect of nitrogen content on the tensile properties of 316LN SS. BI tests were conducted on four different heats of 316LN SS containing 0.07, 0.11, 0.14 and 0.22 wt% nitrogen in the temperature range 300–923 K. The tensile properties such as yield strength and ultimate tensile strength increased with increase in nitrogen content at all the investigated temperatures. These results were consistent with the corresponding uniaxial tensile test results. These studies showed that BI technique can be used to optimize the chemical composition during alloy development by evaluating tensile properties with minimum volume of material.

scholarly journals A Virtual Platform to Determine the Tensile Properties of Engineered Cementitious Composite

2020 ◽  
Vol 22 (2) ◽  
pp. 59-67
Author(s):  
Benny Suryanto ◽  
Joshua Kiyoshi Suryanto
Keyword(s):  
Tensile Properties ◽  
Virtual Environment ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Simple Relationship ◽  
Cementitious Composite ◽  
Flexural Test ◽  
Test Environment ◽  
Engineered Cementitious Composite ◽  
Institute Of Technology

The four-point flexural test is now making headway as an alternative laboratory investigative technique for determining the tensile properties of Engineered Cementitious Composite (ECC) to the more traditional, direct/uniaxial tensile test. As the fundamental mechanics of ECC specimens tested in four-point flexure are well understood, it is possible to develop a simple relationship between flexural test results and the tensile properties of this cement composite. This paper extends this development and aims to provide accessible and quick calculation of the tensile properties of ECC via a virtual test environment. To this end, attention is directed towards the test configurations developed earlier at Heriot-Watt University, the University of Michigan, and Sepuluh Nopember Institute of Technology. In this paper, the technical background employed in creating the virtual environment and the computer implementation using the JavaScript programming language are presented. The prototype virtual environment is freely available via the Internet at https://ecc-calculator.netlify.app/.

scholarly journals Quantifying Tensile Properties of Bamboo Silicone Biocomposite using Yeoh Model

2018 ◽  
Vol 7 (4.26) ◽  
pp. 245 ◽  
Author(s):  
Kamarul Nizam Hassan ◽  
Jamaluddin Mahmud ◽  
Anwar P.P. Abdul Majeed ◽  
Mohd Azman Yahya
Keyword(s):  
Experimental Data ◽  
Tensile Properties ◽  
Coefficient Of Determination ◽  
Elastic Behaviour ◽  
Uniaxial Tensile ◽  
Tensile Behaviour ◽  
Uniaxial Tensile Test ◽  
Constitutive Function ◽  
Yeoh Model ◽  
Fitting Model

The utilisation of bamboo has the potential of improving the properties of silicone. However, a thorough investigation has yet to be reported on the mechanical properties of bamboo silicone biocomposite. This study was carried out with the aim to quantify the tensile properties and assess the tensile behaviour of bamboo silicone biocomposite using Yeoh hyperelastic constitutive function. The specimens were prepared from the mix of bamboo particulate and pure silicone at various fibre composition ratio (0wt%, 1wt%, 3wt% and 5wt%) cured overnight at room temperature. A uniaxial tensile test was carried out by adopting the ASTM D412 testing standard. The Coefficient of Variation, CV, and the Coefficient of Determination, r2, were determined to assess the reliability of the experimental data and fitting model. The results of the determined Yeoh material constants for 5wt% specimen is found to be C1 = 12.0603×10-3 MPa, C2 = 8.7353×10-5 MPa and C3 = -11.6165×10-8 MPa, compared to pure silicone (0wt%) C1 = 5.6087×10-3 MPa, C2 = 8.6639×10-5 MPa and C3 = -7.6510×10-8 MPa. The results indicate that the bamboo fibre improves the stiffness of the silicone rubber by 115 percent. A low variance was exhibited by the experimental data with a CV value of less than 8 percent. The Yeoh Model demonstrated an excellent prediction of the elastic behaviour of bamboo silicone biocomposite with a fitting accuracy of more than 99.93 percent.  

scholarly journals Quantifying Mechanical Properties of Automotive Steels with Deep Learning Based Computer Vision Algorithms

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 163 ◽  
Author(s):  
Ehsan Javaheri ◽  
Verdiana Kumala ◽  
Alireza Javaheri ◽  
Reza Rawassizadeh ◽  
Janot Lubritz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Computer Vision ◽  
Light Microscope ◽  
Indentation Depth ◽  
Indentation Test ◽  
Training Dataset ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Plastic Behavior ◽  
Material Parameters

This paper demonstrates that the instrumented indentation test (IIT), together with a trained artificial neural network (ANN), has the capability to characterize the mechanical properties of the local parts of a welded steel structure such as a weld nugget or heat affected zone. Aside from force-indentation depth curves generated from the IIT, the profile of the indented surface deformed after the indentation test also has a strong correlation with the materials’ plastic behavior. The profile of the indented surface was used as the training dataset to design an ANN to determine the material parameters of the welded zones. The deformation of the indented surface in three dimensions shown in images were analyzed with the computer vision algorithms and the obtained data were employed to train the ANN for the characterization of the mechanical properties. Moreover, this method was applied to the images taken with a simple light microscope from the surface of a specimen. Therefore, it is possible to quantify the mechanical properties of the automotive steels with the four independent methods: (1) force-indentation depth curve; (2) profile of the indented surface; (3) analyzing of the 3D-measurement image; and (4) evaluation of the images taken by a simple light microscope. The results show that there is a very good agreement between the material parameters obtained from the trained ANN and the experimental uniaxial tensile test. The results present that the mechanical properties of an unknown steel can be determined by only analyzing the images taken from its surface after pushing a simple indenter into its surface.

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