scholarly journals Approach for Obtaining Material Mechanical Properties in Local Region of Structure Based on Accurate Analysis of Micro-indentation Test

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
He Xue ◽  
Jinxuan He ◽  
Jianlong Zhang ◽  
Yuxuan Xue

AbstractThe hot or cold processing would induce the change and the inhomogeneous of the material mechanical properties in the local processing region of the structure, and it is difficult to obtain the specific mechanical properties in these regions by using the traditional material tensile test. To accurately get actual material mechanical properties in the local region of structure, a micro-indentation test system incorporated by an electronic universal material test device has been established. An indenter displacement sensor and a group of special micro-indenter assemblies are established. A numerical indentation inversion analysis method by using ABAQUS software is also proposed in this study. Based on the above test system and analysis platform, an approach to obtaining material mechanical properties in the local region of structures is proposed and established. The ball indentation test is performed and combined with the energy method by using various changed mechanical properties of 316L austenitic stainless steel under different elongations. The investigated results indicate that the material mechanical properties and the micro-indentation morphological changes have evidently relevance. Compared with the tensile test results, the deviations of material mechanical parameters, such as hardness H, the hardening exponent n, the yield strength σy, and others are within 5% obtained through the indentation test and the finite element analysis. It provides an effective and convenient method for obtaining the actual material mechanical properties in the local processing region of the structure.

2021 ◽  
Author(s):  
He Xue ◽  
Jinxuan He ◽  
Jianlong Zhang ◽  
Yuxuan Xue

Abstract The welding and other hot or cold processing region behavior in important structures is the key characteristics for the structural integrity assessment, it is necessary to accurately derive the material mechanical properties in the failure driving force (such as stress and strain) analysis in the local area. The hot or cold processing would induce the change and the inhomogeneous of the material mechanical properties in the local processing region of the structure, and it is difficult to obtain the precise mechanical properties in these regions by the traditional material tensile test. To accurately obtain actual material mechanical properties in the local region of structures, a micro-indentation test system has been established, which incorporated by a CMT6103 Material Test Device, an indenter displacement sensor and a group of special micro-indenter assemblies are established, and a numerical testing inversion analysis method by using ABAQUS software is also proposed in this paper. Based on above test system and analysis platform, an approach to obtain material mechanical properties in local region of structure is proposed and established. The verification experiment and analysis is performed by using a group of various changed mechanical property of 316L austenitic stainless steel through different cold-work hardening. The investigated results indicate the material mechanical properties and the micro-indentation morphological change have evidently relevance, and the material mechanical parameters, such as the yield stress σ y , the strain hardening exponent n and others could be conveniently and effectively obtained by the proposed approach in this paper.


2021 ◽  
Author(s):  
Luigi Bruno ◽  
Santo Canto ◽  
Luciano Luciani

Abstract In the present work, authors have demonstrated how a localized induction heat treatment can be advantageously applied, controlled and mechanically characterized on a specific part – i.e. on steel hose fittings for hydraulic applications. More specifically, the study shows how this specific type of heat treatment facilitates the acquisition of significant localization effects on mechanical properties, and how such a treatment could act as a powerful tool for material optimization in diverse applications. The instrumented micro-indentation test was adopted as the investigation method for mechanical characterization and, due to the reduced amount of material required for the test, has the double advantage of retrieving potential spatial gradients of the mechanical properties without causing permanent damage to the entirety of analyzed parts. The measurement of both the Vickers hardness and plastic work required to make the indentation that would be necessary to quantify the strength and ductility capability of the parts’ material. In addition, a customized tensile test, based on the strains measurement obtained through an optical full-field method – i.e. Digital Image Correlation (DIC) – was developed with the aim of identifying and quantifying the correlation between the material properties attainable through a conventional tensile test and those measured by the instrumented micro-indentation test. Finally, it was demonstrated that the proposed customized tensile test, due to the localized heat treatment, is capable of retrieving potential spatial gradients of material properties.


2013 ◽  
Vol 25 (4) ◽  
pp. 603-610 ◽  
Author(s):  
Kaoru Uesugi ◽  
◽  
Yoshitake Akiyama ◽  
Takayuki Hoshino ◽  
Yoshikatsu Akiyama ◽  
...  

In this paper, we present a tensile test system and a new self-attachable fixture for measuring mechanical properties of cell sheets. Previously when measuring the mechanical properties of cell sheets, the sheets would be damaged because they dried out. With our system, the tensile test can be carried out while the cell sheets are in the culture medium, so there is no damage by drying. Previously, it has also been difficult to attach a cell sheet in the tensile test system owing to the structure of the conventional fixture, and there has been no tensile test system which had a measurement range that covered the tension force range of the cell sheets. Therefore, we have addressed these problems by developing a self-attachable fixture and a tensile test system. To confirm suitability of the fixture and test system, we measured mechanical properties of two different kinds of cultured cell sheets, C2C12 (cells mouse myoblast cells) and NIH-3T3 (3T3) cells (mouse fibroblast cells), and of the same kinds of sheets treated with cytochalasin-D. We confirmed differences in mechanical properties for each kind of cell sheet. This indicates that our new fixture and test system are applicable for measurement of mechanical properties of cell sheets without damage of the sheets by drying.


2015 ◽  
Vol 2015.51 (0) ◽  
pp. _203-1_-_203-2_
Author(s):  
Junki HOSHINO ◽  
Kyuhei MATSUDA ◽  
Osamu TAKAKUWA ◽  
Hitoshi SOYAMA

2007 ◽  
Vol 544-545 ◽  
pp. 821-824
Author(s):  
Indra ◽  
S.W. Oh ◽  
Hee Joon Kim

This work examined the mechanical properties of alumina that can directly be enhanced by ratio of nano sized alumina powders additives to micro size alumina powders (n/m ratio). These new materials have mechanical properties that are strongly grain size dependent and often significantly different from those of their coarser grained counter parts. The mechanical characteristics of samples were observed by using the indentation test system. This data shows that the relative density for the sample is increased with increasing Meyer hardness.


2016 ◽  
Vol 368 ◽  
pp. 138-141
Author(s):  
Martin Ovsík ◽  
Vojtech Šenkeřík ◽  
David Manas ◽  
Miroslav Maňas ◽  
Michal Stanek ◽  
...  

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. The aim of the experiments was to study the influence of different doses of Beta radiation to the structure and micro-mechanical properties of polypropylene filled by 30% glass fiber (PP+GF). Hard surface layers of PP+GF can be formed by radiation cross-linking by β – radiation with doses of 33, 66 and 99 kGy. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the PP+GF tested. Micro-mechanical properties increased with increasing value of the dose of irradiation material (increase about 49%). The changes were examined and confirmed by X-ray diffraction.


2015 ◽  
Vol 1120-1121 ◽  
pp. 1179-1182
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Adam Skrobak ◽  
...  

Cross-linking is a process in which polymer chains are associated through chemical bonds. This research paper deals with the possible utilization of irradiated polyamide. Influence of the intensity of irradiation on micro-indentation hardness was investigated. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of micro-indentation test shows increasing in micro-mechanical properties of surface layer. The highest values of micro-mechanical properties were reached radiation dose of 99 kGy, when the micro-mechanical values increased by about 18%.


2014 ◽  
Vol 1025-1026 ◽  
pp. 415-418
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Martin Reznicek ◽  
...  

The presented article deals with the research of micro-mechanical properties in the surface layer of modified Polyamide 66 filled by 30% of glass fibers. These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. Radiation doses used were 0, 15, 30 and 45 kGy for filled Polyamide 66 with the 6% cross-linking agent (triallyl isocyanurate). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the polyamide 66 tested. The highest values of micro-mechanical properties were reached at radiation dose of 30 kGy, when the micro-hardness values increased by about 64%. The aim of the article is to find out the influence of the radiation on the micro-hardness of the modified glass fiber-filled Polyamide 66 (PA66).


Author(s):  
Uezono Masayoshi ◽  
Takakuda Kazuo ◽  
Hiratsuka Taizo ◽  
Ogasawara Takeshi ◽  
Oshima Sho ◽  
...  

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