scholarly journals Effects of Striker Edge Radius on Load-Deflection Curve and Absorbed Energy in Instrumented Charpy Impact Test

2005 ◽  
Vol 91 (5) ◽  
pp. 485-492 ◽  
Author(s):  
Shigeki MORITA ◽  
Toshiro KOBAYASHI ◽  
Mitsuo NIINOMI ◽  
Hiroyuki TODA ◽  
Toshikazu AKAHORI
Keyword(s):  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Deflection Curve ◽  
Absorbed Energy ◽  
Edge Radius ◽  
Load Deflection Curve

Thermal Aging Behavior of Grade CF3M Cast Austenitic Stainless Steels

2017 ◽  
Author(s):  
Yasufumi Miura ◽  
Takashi Sawabe ◽  
Kiyoshi Betsuyaku ◽  
Taku Arai
Keyword(s):  
Fracture Toughness ◽  
Stainless Steels ◽  
Thermal Aging ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Ferrite Phase ◽  
Absorbed Energy ◽  
Aging Conditions ◽  
Charpy Absorbed Energy

In this study, CASSs which were thermally aged at 275–400°C for up to 30000 hrs were investigated using atom probe tomography, Charpy impact test, hardness test, and fracture toughness test in order to evaluate the effects of chemical composition and ferrite content on thermal aging embrittlement. Test materials were 4 types of statically casted grade CF3M stainless steels which are used in Japanese BWR plants. As a result of the tests, Charpy absorbed energy at room temperature of all thermal aging conditions were obtained. We also obtained the microstructural evolution in ferrite phase, hardness of ferrite phase, and J–R curves of several aging conditions. The fracture toughness and the Charpy absorbed energy of all materials aged at 275°C for up to 15000 hrs were approximately same as those of unaged materials. On the other hand, reduction of the fracture toughness and the Charpy absorbed energy were observed in the materials aged at 300°C, 320°C, 350°C and 400°C. For the Charpy impact test in this study, the absorbed energy of the material with highest molybdenum was lower than that of the material with highest ferrite content. After the tests, the fracture toughness estimation model for grade CF8M in NUREG/CR-4513 and the method in PVP2005-71528 (H3T model) were discussed in order to confirm the applicability of the prediction methods to CF3M.

Evaluation of Shear Area of DWTT Fracture Surface With Instrumented System

2009 ◽  
Author(s):  
Seong Soo Ahn ◽  
You Sun Ham
Keyword(s):  
Fracture Toughness ◽  
Fracture Surface ◽  
Dynamic Loading ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Displacement Curve ◽  
Absorbed Energy ◽  
Long Time ◽  
Shear Area

The test method to evaluate fracture toughness can be divided by the loading type to specimen. A static load is given to specimen for testing KIC, JIC, CTOD, etc. while a dynamic load is given to those for testing Charpy impact test, DWTT, etc. In case of fracture toughness tests with static loading, the data of load and displacement should be gathered during test because they were driven from fracture mechanics. In case of fracture toughness tests with dynamic loading, however, we don’t gather any data during specimen broken. We measure an absorbed energy for fracture and shear area from fracture surface after Charpy impact test and a shear area from fracture surface after DWTT. To analyze the results from these toughness tests of dynamic loading type with using fracture mechanics, recently, an instrumented system is installed to these dynamic loading test machines. An instrumented system can measure load and displacement during specimen broken. On the displacement-load curve made with data from an instrumented system, in general, the area in the region before peak-force is the energy for crack initiation while area in the region after peak-force is that for crack propagation. Meanwhile, it takes a long time and effort to evaluate the shear area from both fracture surfaces after Charpy impact test and DWTT test. For Charpy impact test, the method how to calculate the shear area with the information from a load-displacement curve has been studied for a long time. So the method for it is well established and known. For DWTT, however, the method how to calculate the shear area from a load-displacement curve was not known well. In this paper, a shear area could be calculated from an instrumented data without any more time or effort in addition to test. A shear area could be expressed as a function of total absorbed energy, fractured area, maximum force, time at 50kN and time at maximum force. Especially, the material with shear area more than 85% could be distinguished from that with shear area less than 85% because the transition curve of DWTT changes dramatically around 85% shear area.

Correlation of Impact Energy from Instrumented Charpy Impact

2015 ◽  
Vol 815 ◽  
pp. 221-226
Author(s):  
M.B. Ali ◽  
Kamarul Ariffin Zakaria ◽  
Shahrum Abdullah ◽  
M.R. Alkhari
Keyword(s):  
Strain Energy ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Absorbed Energy ◽  
Spectrum Density ◽  
The Time Domain ◽  
Power Law Equation ◽  
Strength And Ductility ◽  
Impact Duration

This paper proposes the correlation of absorbed energy with calculated energy using the power spectrum density (PSD) method. The total absorbed energy was obtained using the dial/encoder system may significantly vary depending on the strength and ductility of the material. In addition, according to ASTM E23, over 80% of absorbed energy is inaccurate and approximate. For this reason, we determined the energy collected from the dial/encoder Charpy impact test using the signal processing approach. Strain gauges were connected to the Charpy impact striker and the high frequency data acquisition system in order to capture the dynamic impact strain response. Specimens of an aluminium alloy of 6061-T6 and carbon steel 1050 with different velocities and thicknesses were used in the experiment. The specimens are prepared based on the ASTM E23. A collection of signal was converted from the time domain to the frequency domain by means of PSD method and the area under its plot was used to calculate strain energy. The comparison between energy absorbed during the experiment with PSD peak and the strain energy were performed using different materials, velocities and thicknesses. The total energy absorbed for both material with the PSD peak and the strain energy using the dial/encoder system can be linked by a power law equation with R2 96% and R2 94 %. Thus, the effects of the strain signal pattern and impact duration with different parameters were correlated with the PSD peak and the strain energy. This correlation using PSD can be used as an alternative for the charpy impact test and solve the problem of inaccurate absorbed energy.

Effects of the Striking Edge Radius on the Charpy Impact Test

2009 ◽  
pp. 67-67-14 ◽  
Author(s):  
T Naniwa ◽  
M Shibaike ◽  
M Tanaka ◽  
H Tani ◽  
K Shiota ◽  
...  
Keyword(s):  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Edge Radius

Ductile-Brittle Transition Behaviors with Two Striker Geometries in the Instrumented Charpy Impact Test

2004 ◽  
Vol 449-452 ◽  
pp. 861-864 ◽  
Author(s):  
Shigeki Morita ◽  
Toshiro Kobayashi
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Test Method ◽  
Absorbed Energy ◽  
Time Curve ◽  
Edge Geometry ◽  
Standard Procedures ◽  
High Level

Instrumented Charpy impact test method is possible to obtain various dynamic fracture characteristics from the load-deflection or load-time curve. Recently, instrumented Charpy impact test method is widely used for the evaluation of toughness of various specimens of different materials with different sizes. It is important to record an accurate impact load in order to improve the reliability of this test method. In some standards of instrumented Charpy impact test method such as ISO and ASTM, they haven.t clearly standardized striker geometry which seem to directly influence the obtained impact load. There are some differences between standards, although standard procedures are well defined. Therefore, instrumented Charpy impact test method has a problem that measurement value is different depending on each standard. In the present study, the effect of striking edge geometries, which are difference between ISO and ASTM, on load-deflection curve and absorbed energy were investigated. According to ISO and ASTM, two types of striker having different radius were machined. There was no difference between the two different striking edge geometries for values of absorbed energy per unit ligament area less than 0.75J/mm2. However, striking edge geometry according to ASTM is not propriety for Charpy impact test method because of four, instead of three, point bending on process of fracture at high level of absorbed energy. The effect of brinelling deformation, which was considered as an advantage of striking edge geometry according to ASTM, is very small on instrumented Charpy impact test. Consequently, there seem to be not an advantage of striking edge geometry according to ASTM. Therefore, standards should be unified in the striking edge geometry according to ISO.

scholarly journals Quality assurance of absorbed energy in Charpy impact test

2016 ◽  
Vol 733 ◽  
pp. 012009
Author(s):  
C L F Rocha ◽  
D A K Fabricio ◽  
V M Costa ◽  
A Reguly
Keyword(s):  
Quality Assurance ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Absorbed Energy

scholarly journals Analysis of Ductile Fracture Obtained by Charpy Impact Test of a Steel Structure Created by Robot-Assisted GMAW-Based Additive Manufacturing

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1208 ◽  
Author(s):  
Ali Waqas ◽  
Xiansheng Qin ◽  
Jiangtao Xiong ◽  
Chen Zheng ◽  
Hongbo Wang
Keyword(s):  
Fracture Toughness ◽  
Impact Test ◽  
Gas Metal Arc Welding ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Wall Structure ◽  
Layer By Layer ◽  
Thin Wall ◽  
Absorbed Energy ◽  
Secondary Cracks

In this study, gas metal arc welding (GMAW) was used to construct a thin wall structure in a layer-by-layer fashion using an AWS ER70S-6 electrode wire with the help of a robot. The Charpy impact test was performed after extracting samples in directions both parallel and perpendicular to the deposition direction. In this study, multiple factors related to the resulting absorbed energy have been discussed. Despite being a layered structure, homogeneous behavior with acceptable deviation was observed in the microstructure, hardness, and fracture toughness of the structure in both directions. The fracture is extremely ductile with a dimpled fibrous surface and secondary cracks. An estimate for fracture toughness based on Charpy impact absorbed energy is also given.

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