Subsized Specimens for Fracture Resistance Characterisation Including Transferability Issues

2017 ◽  
Vol 741 ◽  
pp. 110-115
Author(s):  
Ivo Dlouhý ◽  
Luděk Stratil ◽  
Filip Šiška
Keyword(s):  
Fracture Resistance ◽  
Small Punch Test ◽  
Ductile Materials ◽  
Punch Test ◽  
Damage Quantification ◽  
Scaling Models ◽  
Low Constraint ◽  
Basic Approaches ◽  
Shelf Region

The contribution is focused on characterization of methods enabling to apply small/subsized specimens for fracture resistance characterization. The applied methods are divided into transition region and upper shelf region. The approaches used in the upper shelf region represent at the same time methods applicable for ductile materials without transition. Relating to subsized samples two basic approaches are applicable: (i) miniaturized samples based on common standard ones and (ii) specific specimens/methods, e.g. small punch test etc. The results described in the paper belong to the first group. For interpretation of data generated under low constraint conditions toughness scaling models and master curve approached are commented. In ductile region, either the sample used generate valid toughness characteristics, or, if not, there is no way how to correct measured data except damage quantification through micromechanical models.

Influence of the Residual Stress on Mechanical Properties of Ductile Materials by Simulating Small Punch Test

2015 ◽  
Vol 750 ◽  
pp. 285-291
Author(s):  
He Hui Wang ◽  
Shao Jie Zhang ◽  
Yao Gang Wang ◽  
Kai Shu Guan
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Material Behavior ◽  
Small Punch Test ◽  
Small Punch ◽  
Ductile Materials ◽  
Punch Test ◽  
Original Specimen ◽  
Loading And Unloading ◽  
Simulated Material

This paper describes an approach to identify the influence of mechanical properties of the materials under the condition of containing residual stress. The numerical method of simulating small punch test (SPT) is used to determine the material response under loading. The simulated material behavior of the specimen is based on the ductile elastoplastic damage theory of Gurson, Tvergaard and Needleman (GTN). The residual stress can be prefabricated on the specimen by loading and unloading. By comparing the original specimen with the specimen contains residual stress, the change of the mechanical properties of the materials can be studied. The results of simulation indicate that the material properties decrease with the increase of the residual stress.

Small Punch Testing of Exposed High-Pressure Steam Pipelines

2013 ◽  
Author(s):  
Petr Dymáček ◽  
Ferdinand Dobeš
Keyword(s):  
Residual Life ◽  
Tensile Creep ◽  
Small Punch Test ◽  
Small Punch ◽  
Punch Test ◽  
Pressure Steam ◽  
Material Sample ◽  
Steam Pipes ◽  
Deflection Rate

Non-disruptive material sample scooping is frequently applied to a range of operating components since it is supposed that removal of small amount of material from the surface has no effect on components integrity. As-removed material is then subjected to mechanical testing by small punch test to estimate tensile, creep and fracture properties necessary for assessment of residual life of the component. The question arises whether the assumption that measurements on surface specimens are representative for the characterization of whole component is justified. For the verification of this assumption, four steam pipes after either plant- or simulated-exposure up to 104 000 hours were used. Small punch specimens were prepared from different positions within pipes. The dimensions of specimens enable to estimate mechanical properties for several dozens of specimens along available power-plant pipes’ walls. The paper summarizes the results of small punch tests at both constant deflection rate and constant force and at room and elevated temperature, respectively. In the walls of the investigated pipes, the results obtained on surface specimens do not differ substantially from the results on specimens prepared from central parts.

High-temperature small punch test for mechanical characterization of a nickel-base super alloy

2014 ◽  
Vol 613 ◽  
pp. 259-263 ◽  
Author(s):  
S. Soltysiak ◽  
M. Selent ◽  
S. Roth ◽  
M. Abendroth ◽  
M. Hoffmann ◽  
...  
Keyword(s):  
High Temperature ◽  
Mechanical Characterization ◽  
Small Punch Test ◽  
Small Punch ◽  
Punch Test ◽  
Nickel Base ◽  
Super Alloy

Characterisation of Mechanical Properties by Small Punch Test

2014 ◽  
Vol 606 ◽  
pp. 15-18 ◽  
Author(s):  
Jan Siegl ◽  
Petr Haušild ◽  
Adam Janča ◽  
Radim Kopřiva ◽  
Miloš Kytka
Keyword(s):  
Mechanical Properties ◽  
Coming Out ◽  
Nuclear Power ◽  
Power Plants ◽  
Fracture Toughness Test ◽  
Small Punch Test ◽  
Charpy Test ◽  
Small Punch ◽  
Punch Test

The specific desired properties for structures and components working in critical environments (e.g. different structure parts of power plants) require current information about degradation processes coming out in materials. Obtaining of this information by the help of the classical tests of mechanical properties (tensile test, Charpy test, fracture toughness test, creep test etc.) is very limited namely in the case of nuclear power plants pressure vessel. Hence, the new innovative techniques based on miniaturized specimens have been developed for evaluation of mechanical properties and their changes. One of very promising techniques is Small Punch Test. Present paper deals with characterization of three different steels (15Ch2MFA, 10GN2MFA with different heat treatment and steel O8Ch18NT10 with various degree of deformation).

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