Experiments on a Ring Tension Setup and FE Analysis to Evaluate Transverse Mechanical Properties of Tubular Components

Author(s):  
M.K. Samal ◽  
K.S. Balakrishnan

Determination of transverse mechanical properties from ring specimens machined from tubular components is not straightforward due to presence of combined tension and bending stresses. Zircaloy tubes as used in nuclear reactors are manufactured through a complicated process of pilgering and heat-treatment and hence, the properties need to be determined in the as-manufactured condition. In this work, the authors perform ring-tensile tests on specimens of Zircaloy pressure tubes of Indian pressurized heavy water reactor in order to carry out integrity assessment of these tubes. As the loading condition in this test imposes both membrane and bending stresses in the cross-section of the ring, 3-D finite element analysis of the test setup was carried out in order to determine material stress-strain curve using an iterative technique. The effect of the design of the loading mandrel on the experimental stress-strain data has been investigated in detail. To validate the methodology, miniature tensile specimens have been tested and the data has been compared to those of ring specimens.


2019 ◽  
Vol 9 (17) ◽  
pp. 3474
Author(s):  
Dong Seok Shin ◽  
Young Shin Kim ◽  
Euy Sik Jeon

Studying the characteristics of materials through a finite element analysis (FEA) has various benefits; hence, many studies have been conducted to improve the reliability of the analysis results. In general, the mechanical properties used in FEA for metals and metal composites are stress–strain data obtained through tensile tests, which are used for modeling from a macroscopic perspective. While many studies have been conducted on metal materials, there are limited studies on the analysis of polymer composite materials produced through injection and special processing. In this study, existing inverse methods were applied, and an FEA was conducted to reproduce the axial displacement of the tensile specimens comprising glass fiber-reinforced polymer (GFRP); further, errors were examined by comparing the test and analysis results. To reduce such errors, the experiment and the FEA results were analyzed through parameter optimization based on various empirical formulas. The accuracy of various inverse methods were examined and an inverse method suitable for GFRP was proposed.



Author(s):  
K.-D. Bouzakis ◽  
A. Lontos

The determination of the mechanical properties using the nano or macroindentation test results was developed in order to predict the mechanical properties of materials such as thin or thick coatings [1]. In the present paper a new method using a continuous FEM supported simulation of the microindentation results through a special tester, is proposed in order to predict the stress–strain curve of various ferrous or non ferrous materials that are being used as constructive materials in several machines or devices. The elasticity modulus is determined using a large spherical indenter tip and the stress strain curve using smaller steel balls. In the case of three deferent ball diameter indenter tips, the adopted experimental-analytical methodology present similar results regarding the constitutive law of the examined steel or aluminum specimens.



2010 ◽  
Vol 636-637 ◽  
pp. 1186-1193 ◽  
Author(s):  
A.M.S. Dias ◽  
G.C.D. Godoy

Instrumented indentation testing is a technique widely used in different materials to evaluate the penetration depth in function of the indenter load. Considering Berkovich indenter, this methodology has been used to determine mechanical properties such as hardness, Young modulus and a stress versus strain curve of the elastic-plastic behaviour under compression of the tested materials. However, the implementation of this technique to evaluate mechanical properties and also its results have still brought doubts on research areas. Nowadays, the use of a numerical methodology able to evaluate the stress and strain fields during indentation cycle can lead to a more secure interpretation. The aim of this work was to simulate the Berkovich indentation testing and to propose a methodology to extract the stress-strain curve through experimental and numerical analyses. The obtained numerical results for the load-displacement curve were quite similar to the experimental curve presented in the literature.



Author(s):  
Jan Brumek ◽  
Bohumi´r Strnadel ◽  
Ivo Dlouhy´

This work is concerned with the method for predicting stress-strain behavior of material using instrumented indentation technique. High strength low alloy steel with different thermal treatment was taken into the analysis. Heat treatment for the steel was performed to obtain different mechanical properties. Assessment of mechanical properties was done by using inverse technique of the finite element analysis. The results were confronted with conventional test parameters and prediction procedure defined such Automated Ball Indentation Technique (ABIT). Comparison of the material curves shows good agreement with tensile test properties which makes this non-destructive method suitable for industrial application.



Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.



Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3626
Author(s):  
Łukasz Hojdys ◽  
Piotr Krajewski

This paper presents the results of direct tensile tests performed on six different FRCM (fabric reinforced cementitious matrix) strengthening systems used for masonry structures. The emphasis was placed on the determination of the mechanical parameters of each tested system and a comparison of their tensile behaviour in terms of first crack stress, ultimate stress, ultimate strain, cracking pattern, failure mode and idealised tensile stress-strain curve. In addition to the basic mechanical tensile parameters, accidental load eccentricities, matrix tensile strengths, and matrix modules of elasticity were estimated. The results of the tests showed that the tensile behaviour of FRCM composites strongly depends on the parameters of the constituent materials (matrix and fabric). In the tests, tensile failure of reinforcement and fibre slippage within the matrix were observed. The presented research showed that the accidental eccentricities did not substantially affect the obtained results and that the more slender the specimen used, the more consistent the obtained results. The analysis based on a rule of mixtures showed that the direct tensile to flexural tensile strength ratio of the matrixes used in the test was 0.2 to 0.4. Finally, the tensile stress–strain relationship for the tested FRCMs was idealised by a bi- or tri-linear curve.



2006 ◽  
Vol 114 ◽  
pp. 171-176 ◽  
Author(s):  
Joanna Zdunek ◽  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski

In this work, Al-Mg-Mn-Si alloy (5483) in the as-received and severe plastically deformed states was used. Plastic deformation was carried out by hydrostatic extrusion, and three different true strain values were applied 1.4, 2.8 and 3.8. All specimens were subjected to tensile tests and microhardness measurements. The investigated material revealed an instability during plastic deformation in the form of serration on the stress-strain curves, the so called Portevin-Le Chatelier effect It was shown that grain size reduction effected the character of the instability.



1986 ◽  
Vol 18 (5) ◽  
pp. 664-668
Author(s):  
M. V. Shakhmatov ◽  
V. V. Erofeev ◽  
V. A. Lupin ◽  
A. A. Ostsemin


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