scholarly journals Numerical Research of Fracture Toughness of Aged Ferritic-Martensitic Steel

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1686
Author(s):  
Remigijus Janulionis ◽  
Gintautas Dundulis ◽  
Albertas Grybėnas
Keyword(s):  
Fracture Toughness ◽  
Numerical Method ◽  
Experimental Tests ◽  
Thermal Ageing ◽  
Experimental Conditions ◽  
Finite Element Software ◽  
Numerical Research ◽  
Determination Methods ◽  
Good Coincidence

Generally, material properties such as the modulus of elasticity, yield strength or fracture toughness are determined by conducting an experiment. Sometimes experimental determination cannot be done due to specific experimental conditions, lack of testing material and so on. Also, experiments are time consuming and costly. Therefore, there arises the need for alternative determination methods. A numerical method for the fracture toughness determination of steel P91 is suggested in this paper. For this purpose, the universal finite element software ABAQUS was used. The numerical simulation of the C(T) specimen tension test was carried out using non-linear simulation for a conditional load PQ determination, and linear simulation for fracture toughness value KQ determination. The suggested method is validated by comparing numerical and experimental tests results. The secondary aim of the paper is the evaluation of the ageing effect on the fracture toughness of steel P91. Thermal ageing of the steel was carried out in an electric furnace at 650 °C up to 11,000 h. As the numerical results had a good coincidence with experimental data at room temperature, the prediction of fracture toughness at elevated temperature, i.e., 550 °C, using numerical method was carried out.

scholarly journals Determination of ASI and THIV parameters based on the results of experimental and numerical research in relation to EU standards

2021 ◽  
Vol 338 ◽  
pp. 01025
Author(s):  
Michał Stopel
Keyword(s):  
Experimental Tests ◽  
Severity Index ◽  
Point Of View ◽  
The Finite Element Method ◽  
Safety Level ◽  
The Road ◽  
Road Sign ◽  
Numerical Research ◽  
Python Programming

Determining the values of ASI (Acceleration Severity Index) and THIV (Theoretical Head Impact Velocity) parameters during tests allows you to assign an appropriate class for a given type of object to determine the safety level and to give the CE marking. The paper presents the methodology for determining these parameters based on the EN 1317-1 and EN 12767 standards. The paper also presents a tool created with the use of the Python programming language, which, based on the results of experimental tests or the results of numerical calculations, allows to determine the ASI and THIV values. The values of key parameters from the point of view of normative tests were calculated based on the results of experimental tests of the road sign supporting mast and numerical analysis carried out for the same case using the Finite Element Method and LS-Dyna software, following the EN 12767 standard.

scholarly journals Experimental Testing and Numerical Simulations for Typical Swelling Soil in Egypt

2019 ◽  
Vol 8 (3) ◽  
pp. 4101-4111
Keyword(s):  
Experimental Testing ◽  
Experimental Tests ◽  
Soil Samples ◽  
Test Facility ◽  
Testing Program ◽  
Swelling Soils ◽  
Urban Regions ◽  
Finite Element Software ◽  
Swelling Soil

swelling soils exist in many developing urban regions in egypt. Most of these urban regions have new huge developments under constructions. The structures constructed on these swelling soils may be exposed to high damage if any significant change in the moisture content of these swelling soils occures, so the presence of such swelling soils represents a significant hazard. Investigation the behaviour of these swelling soils as well as determination of their swelling parameters has become highly necessary. In this paper, intensive experimental testing program has been conducted on some soil samples collected from some of these regions to determine their swelling parameters. Through this experimental testing program, oedometer swell test has been firstly conducted on same soil with two different techniques; namely different pressure method and huder-amberg method. The procedures and obtained results of the two used methods are discussed and compared showing advantages and shortages of each method. After that, all subsequent experimental tests were perfomred using huderamberg method as it demonstrated high superiority in determining swelling parameters. Grob’s 1d swelling law was applied to all obtained experimental results to give exact and complete determination for all swelling parameters. Furthermore, swelling soil has been simulated numerically via the new userdefined swelling constitutive model which has been recently implemented for the finite element software plaxis. The suitability of this model to simulate the performance of swelling soil is verified by conducting a numerical simulation to one of the huder-amberg oedometer tests through the oedometer soil test facility available in plaxis software. Finally, based on the aboveselected experimental approach, swelling parameters were determined from the experimental tests conducted on different soil samples collected from some selected arid/semi-arid regions in egypt. Such test results were summarized and presented as a useful key-parameters of these swelling soils which can be used as pre-determined inputs in any further numerical analyses.

Antithrombin-mediated Inhibition of Factor Vlla-Tissue Factor Complex by the Synthetic Pentasaccharide Representing the Heparin Binding Site to Antithrombin

1996 ◽  
Vol 76 (01) ◽  
pp. 005-008 ◽  
Author(s):  
Jean Claude Lormeau ◽  
Jean Pascal Herault ◽  
Jean Marc Herbert
Keyword(s):  
Binding Site ◽  
Tissue Factor ◽  
Residual Activity ◽  
Coagulation Factors ◽  
Heparin Binding ◽  
Experimental Conditions ◽  
First Order ◽  
Heparin Binding Site ◽  
Coagulant Activity

SummaryWe examined the effect of the synthetic pentasaccharide representing the minimal binding site of heparin to antithrombin on the antithrombin-mediated inactivation of factor Vila bound to tissue factor. This effect was compared to the effect of unfractionated heparin. Using purified recombinant human coagulation factors and either a clotting or an amidolytic assay for the determination of the residual activity of factor Vila, we showed that the pentasaccharide was an efficient antithrombin-dependent inhibitor of the coagulant activity of tissue factor-factor Vila complex. In our experimental conditions, assuming a mean MW of 14,000 for heparin, the molar pseudo-first order rate constants for ATIII-mediated FVIIa inhibition by ATIII-binding heparin and by the synthetic pentasaccharide were found to be similar with respective values of 104,000 ± 10,500 min-1 and 112,000 ± 12,000 min-1 (mean ± s.e.m., n = 3)

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