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Number of results: 88
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Abstract

To investigate the mechanical properties of tunnel lining concrete under different moderate-low strain rates after high temperatures, uniaxial compression tests in association with ultrasonic tests were performed. Test results show that the ultrasonic wave velocity and mass loss of concrete specimen begin to sharply drop after high temperatures of 600°C and 400°C, respectively, at the strain rates of 10‒5s‒1 to 10‒2s‒1. The compressive strength and elastic modulus of specimen increase with increasing strain rate after the same temperature, but it is difficult to obtain an evident change law of peak strain with increasing strain rate. The compressive strength of concrete specimen decreases first, and then increases, but decreases again in the temperatures ranging from room temperature to 800°C at the strain rates of 10‒5s‒1 to 10‒2s‒1. It can be observed that the strain-rate sensitivity of compressive strength of specimen increases with increasing temperature. In addition, the peak strain also increases but the elastic modulus decreases substantially with increasing temperature under the same strain rate.

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Authors and Affiliations

L.X. Xiong
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Abstract

The paper presents a method of measuring deformations of cylindrical samples on the testing machine for free tube hydroforming experiments. During experiments a sample made of a thin-walled metal tube is expanded by the internal pressure of the working liquid and additionally subjected to axial compression. This results in a considerable circumferential deformation of the tube and its shortening. Analysis of the load cases and their impact on the deformations can be helpful in determining e.g. tube material properties or general limiting conditions in the tube hydroforming process. In connection with the above, the value of deformations and knowledge of their course during experiment has become one of the most important problems related to the issue described above.

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Authors and Affiliations

H. Sadłowska
Ł. Morawiński
C. Jasiński
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Abstract

The paper presents Finite Elements Method numerical analysis of strength of friction pairs most often used in hip and knee joints alloplasty. Analytic solutions are to indicate and define the areas where damages or premature wear of cooperating elements may occur. Analytical-experimental research states complete and thorough analysis. Accurate technical simulation of the joints of the human motor system, is difficult to conduct due to high level of complexity of human bio-bearings. All attempts to simulate the work of human joints, lead only to an approximate reflection of real human joint motion. To properly face the above problems, along with numerical analysis, there have been conducted empirical tests on the simulator of knee joint endoprosthesis
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Authors and Affiliations

M. Nabrdalik
1
ORCID: ORCID
M. Sobociński
1
ORCID: ORCID

  1. Czestochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation, 21 Armii Krajowej Av ., 42-201 Czestochowa, Poland
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Abstract

Coal ash produced from thermal power plants as a substitute for conventional construction material has increased considerably in recent years. In the past, studies on partial replacement of soil were carried out with a single type of ash. Because of the insufficient evidence, limited research has been initiated on the productive usage of Fly and Bottom Ashes. This paper aims to study the properties of these materials and investigate their efficacy in road construction. Laboratory investigations were conducted to assess chemical and physical properties and mechanical performance to evaluate both ash types in pavement construction. The rutting factor is calculated for various combinations of coal ash materials with the addition of polypropylene fiber as a reinforcement in increments of 0.1% of its total weight with an aspect ratio of 200. The analytical tool ANSYS is used to validate the service life, vertical strain and quality of reinforced ash materials.

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Authors and Affiliations

S.M. Subash
N. Mahendran
M. Manoj Kumar
M. Nagarajan
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Abstract

The main objective of this study is to develop an echocardiographic model of the left ventricular and numerical modeling of the speckles- markers tracking in the ultrasound (ultrasonographic) imaging of the left ventricle. The work is aimed at the creation of controlled and mobile environment that enables to examine the relationships between left ventricular wall deformations and visualizations of these states in the form of echocardiographic imaging and relations between the dynamically changing distributions of tissue markers of studied structures.

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Authors and Affiliations

Robert Olszewski
Andrzej Nowicki
Janusz Wójcik
Zbigniew Trawiński
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Abstract

Mechanical properties of the pipeline samples that had been cut in annular and axial directions were investigated. The methodology of modeling and calculation of the real stress-strain state was described. The stable state during in the deformation process was defined. The results of the experimental researches were used as a test variant during examination of pipe strength.

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Authors and Affiliations

Jerzy Małachowski
Volodymyr Hutsaylyuk
Petr Yukhumets
Roman Dmitryenko
Grigorii Beliaiev
Ihor Prudkii
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Abstract

The study of the geometry for worm-gearing is much more complicated than that of plane gearing, since worm-gearing is three-dimensional. A numerical method to determine the conjugate profile of worm-gearing tooth is developed. The software, with numerical set-up and graphic display, is an original and special program, and it could be adopted for the geometry of any kind of cylindrical worm-gearings, as well as for spur gearings and bevel gearings.
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Authors and Affiliations

Daniela Ghelase
Luiza Daschievici
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Abstract

In the present paper, the excavation of the energetic approach that estimates the fatigue crack initiation life of metal is conducted for H62 brass. The benefit of the energetic approach is the division of the actual applied strain range Δε into two parts, that is, a damage strain range Δεd that induces fatigue damage within the metal, and an undamaged strain range Δεc, which does not produce fatigue damage of the metal and corresponds to theoretical strain fatigue limit. The brightness of this approach is that the undamaged strain range Δεc can be estimated by the fundamental conventional parameters of metal in tensile test. The result indicated that the fatigue crack initiation life of H62 brass can be estimated by this approach successfully.
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Authors and Affiliations

M. Zheng
1
ORCID: ORCID
S. Zhang
1
ORCID: ORCID
X.J. Peng
1
ORCID: ORCID
Y. Wang
1
ORCID: ORCID

  1. Northwest University, School of Chemical Engineering, Xi’an 710069, P. R. China
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Abstract

The paper presents a new method for measuring the strain and load of wire ropes guide using fiber optic sensors with Bragg gratings. Its principle consists in simultaneous fiber optic measurement of longitudinal strain of the rope and transverse strain of the bolt fixing the rope. The tensometric force transducers which have been used so far were only able to determine the load in the head securing the rope through an indirect measurement using a special strain insert. They required calibration, compensation of temperature changes, as well as periodic checking and calibration. The head fastening the rope required significant design changes. Measurement based on fiber optic sensors does not have these drawbacks and is characterized by a much higher accuracy and safety of measurements, because the working medium is light. The fastening head does not change. The measurement of the rope load may be based on the change of strain value or indirectly by means of measuring the deflection of the bolt fixing the rope holder. The proposed solution consists in placing the optical fiber with Bragg grating inside the bolt. It enables continuous measurements with a frequency of 2 kHz. A special test bench was built at the Research and Supervisory Centre of Underground Mining. Testing on guide ropes was carried out in a mining hoist in the Piast mine.
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Authors and Affiliations

Janusz Juraszek
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Abstract

The brake linkage of a hoisting machine is a very important component determining the safety of

the hoisting machine’s entire braking system. It is subject to weekly inspections. However, an efficiency

test of brake performance is carried out every 6 months. Once every 3 years, a test must be carried out by

an appraiser who pays particular attention to the executive and control components of the brakes as well

as the strain - brake system and brake release components. The legal provisions regulating the testing

of braking system linkages are not precise. So far, the control has been based on random measurement

of strains using electrical resistance strain gauges stuck to the surface of the linkage. A new method

for measuring the strains of the linkage has been proposed in the work. It is based on fibre optic strain

sensors with Fibre Bragg Gratings (FBG). They are mounted using specially designed and tested holders

for mounting on the brake linkage. They provide quick assembly and the measurement of strain in the

direction parallel to the axis of the linkage. The structure of the holder also allows for the measurement

in 4 positions turned every 90 relative to one another. Such a measurement enables a comprehensive

analysis of strains and stresses in the brake linkage. In the work, it was shown that there is a complex

state of strain and stress in the brake linkage. The previous procedures for linkage testing are inadequate

in relation to this condition. An experimental and numerical method was proposed to assess the state

of linkage stress. It should constitute the basis for the decision of the appraiser to allow the linkage for

further use. The method proposed in the work also allows for continuous measurements of linkage strains

as well as dynamic braking tests.

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Authors and Affiliations

Janusz Juraszek
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Abstract

A number of micromechanical investigations have been performed to predict behaviour of composite interfaces, showing that the detailed behaviour of the material at these interfaces frequently dominates the behaviour of the composite as a whole. The interfacial interaction is an extremely complex process due to continuous evolution of interfacial zones during deformation and this is particularly true for carbon nanotubes since the interfacial interaction is confined to the discrete molecular level. The atomic strain concept based upon Voronoi tessellation allows analyzing the molecular structure atom by atom, which may give a unique insight into deformation phenomena operative at molecular level such as interface behaviour in nanocomposites.

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Authors and Affiliations

R. Pyrz
B. Bochenek
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Abstract

Single point incremental forming process is a most economical Die-less forming process. The major constraint of it is that it is a time consuming process. In this work, a new attempt was made in incremental forming process using Multipoint tool for SS430 sheets to increase the formability and to reduce forming time. Fractography analysis was made to study the size of voids that were formed during fracture. The forming limit diagrams were drawn and compared for single point incremental forming and the multipoint incremental forming of SS430 sheet. It was proved that the formability of SS430 sheet in the multipoint forming was better than the formability of that in single point forming and the time consumed was reduced. The strain distribution in both processes had also been studied along with surface roughness.

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Authors and Affiliations

K. Ramkumar
G. Paulraj
K. Elangovan
C. Sathiya Narayanan
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Abstract

An optimal sensor placement methodology is implemented and herein proposed for SHM model-assisted design and analysis purposes. The kernel of this approach analysis is a genetic-based algorithm providing the sensor network layout by optimizing the probability of detection (PoD) function while, in this preliminary phase, a classic strain energy approach is adopted as well established damage detection criteria. The layout of the sensor network is assessed with respect to its own capability of detection, parameterized through the PoD. A distributed fiber optic strain sensor is adopted in order to get dense information of the structural strain field. The overall methodology includes an original user-friendly graphical interface (GUI) that reduces the time-to-design costs needs. The proposed methodology is preliminarily validated for isotropic and anisotropic elements.

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Bibliography

[1] C. Boller, F.K. Chang, and Y. Fujino. Encyclopedia of Structural Health Monitoring. John Wiley & Sons Ltd., Chichester, UK, 2009.
[2] M.I. Friswell. Damage identification using inverse methods. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 365(1851):393–410, 2007. doi: 10.1098/rsta.2006.1930.
[3] S. Zhou, Y. Bao, and H. Li. Optimal sensor placement based on substructure sensitivity. In Proceedings of SPIE, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, volume 8345, 2012. doi: 10.1117/12.915074.
[4] D.C. Kammer and M.L. Tinker. Optimal placement of triaxial accelerometers for modal vibration tests. Mechanical Systems and Signal Processing, 18(1):29–41, 2004. doi: 10.1016/S0888-3270(03)00017-7.
[5] M. Najeeb and V. Gupta. Energy efficient sensor placement for monitoring structural health. International Electronic Conference on Sensors and Applications, 1–16 June 2014. doi: 10.3390/ecsa-1-d008.
[6] W. Liu, W.C. Gao, Y. Sun, and M.J. Xu. Optimal sensor placement for spatial lattice structure based on genetic algorithms. Journal of Sound and Vibration, 317(1–2):175–189, 2008. doi: 10.1016/j.jsv.2008.03.026.
[7] H. Gao and J.L. Rose. Sensor placement optimization in structural health monitoring using genetic and evolutionary algorithms. Proceedings of SPIE, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, volume 6174, 2006. doi: 10.1117/12.657889.
[8] X. Bao and L. Chen. Recent progress in Brillouin scattering based fiber sensors. Sensors, 11(4):4152–4187, 2011. doi: 10.3390/s110404152.
[9] L. Maurin, P. Ferdinand, F. Nony, and S. Villalonga. OFDR distributed strain measurements for SHM of hydrostatic stressed structures: an application to high pressure hydrogen storage type IV composite vessels – H2E Project. 7th European Workshop on Structural Health Monitoring, pages 930–937, Nantes, France, 8–11 July, 2014.
[10] O. Shapira, U. Ben-Simon, A. Bergman, S. Shoham, B. Glam, I. Kressel, T. Yehoshula, and M. Tur. Structural health monitoring of a UAV fleet using fiber optic distributed strain sensing. International Workshop on Structural Health Monitoring, Stanford, CA, USA, 1–3 September, 2015. doi: 10.12783/SHM2015/371.
[11] J. Li, R.K. Kapania, andW. B. Spillman. Placement optimization of distributed-sensing fiber optic sensors using genetic algorithms, AIAA Journal, 46(4):824–836, 2008. doi: 10.2514/1.25090.
[12] H. Li, H. Yang, and S.-L.J, Hu. Modal strain energy decomposition method for damage localization in 3D frame structures. Journal of Engineering Mechanics, 132(9):41–951, 2006. doi: 10.1061/(ASCE)0733-9399(2006)132:9(941).
[13] H.-W. Hu and C.-B. Wu. Non-destructive damage detection of two dimensional plate structures using modal strain energy method. Journal of Mechanics, 24(4):319–332, 2008. doi: 10.1017/S1727719100002458.
[14] Z.Y. Shi, S.S. Law, and L.M. Zhang. Improved damage quantification from elemental modal strain energy change. Journal of Engineering Mechanics, 128(5):521–529, 2002. doi: 10.1061/(ASCE)0733-9399(2002)128:5(521).
[15] M. Ciminello, A. Concilio, B. Galasso, and F.M. Pisano. Skin-stringer debonding detection using distributed dispersion index features. Structural Health Monitoring, 17(5):1245–1254, 2018. doi: 10.1177/1475921718758980.
[16] P.O. Mensah-Bonsu. Computer-aided Engineering Tools for Structural Health Monitoring under Operational Conditions. Master’s Thesis, University of Connecticut, USA, 2012. https://digitalcommons.uconn.edu/gs_theses/278.
[17] R. Mason, L.A. Ginter, M. Singleton, V.F. Hock, R.G Lampo, and S.C. Sweeney. A novel integrated monitoring system for structural health management of military infrastructure, Proceedings of Department of Defense Corrosion Conference, 2009.
[18] S. Beskhyroun. Graphical interface toolbox for modal analysis. Proceedings of the Ninth Pacific Conference on Earthquake Engineering: Building an Earthquake-Resilient Society, Auckland New Zealand, 14–16 April 2011.
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Authors and Affiliations

Salvatore Ameduri
1
Monica Ciminello
1
Ignazio Dimino
1
Antonio Concilio
1
Alfonso Catignani
2
Raimondo Mancinelli
2

  1. Centro Italiano Ricerche Aerospaziali, CIRA, Capua, Italy.
  2. Universitá degli Studi di Napoli ‘Federico II’, Napoli, Italy.
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Abstract

Potato virus Y (PVY) is one of the most destructive viruses infecting potato in Egypt and worldwide. Recent research has shown that a necrotic PVY-NTN strain is infecting potato in Upper Egypt. Chemical control is not effective to control this viral pathogen. An alternative to control PVY infecting potato is using a mild PVY strain to elicit systemic cross protection in potato plants against infection with a severe necrotic strain of PVY. Results of this study showed that a PVY necrotic strain produced a significant lesser number of local lesions on diagnostic plants (Robinia pseudoacacia L.) when these plants were treated first with a mild PVY strain. Data obtained from greenhouse and field experiments indicated that treatment of potato plants (variety Burna) with a mild PVY strain significantly protected potato from infection with a severe necrotic PVY strain, and resulted in a significant increase in tuber yield compared with infected plants without prior treatment with a mild PVY strain. The highest increase in potato tuber yield was obtained when potato plants were inoculated with a mild PVY strain 3 days before challenging with the severe necrotic PVY strain. This study proved that using a mild strain of PVY can significantly protect potato plants from infection with a severe strain of this virus under both greenhouse and field conditions and can present a potential method to reduce losses due to infection of this virus in Assiut governorate and Upper Egypt.
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Authors and Affiliations

Osama A. Abdalla
Amal I. Eraky
Safynaz A. Mohamed
Fikry G. Fahmy
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Abstract

This article describes some selected aspects of a preliminary treatment of measurement cycle results obtained by a new Pen206_18 type hydraulic borehole penetrometer (a borehole jack type), a tool of an in situ determining of mechanical properties of rocks. The pre-treatment of the measurement cycle results is a necessary step to prepare the data for a following appropriate analysis of stress-strain parameters of rocks. Aforementioned aspects are focused mainly on a pre-treatment of hydraulic pressure readouts.
The Pen206_18 type penetrometer is a modified version of a standard Pen206 type penetrometer. The standard version, based on a digital measurement of a critical hydraulic pressure, has been in use in polish hard coal mines for almost 15 years to determine various rock strength parameters. In contrary, the Pen206_18 type penetrometer now provides simultaneous recording of two main measurement cycle parameters (hydraulic pressure and a head pin stroke) during the whole measurement cycle duration. A recent modification of the penetrometer has given an opportunity to look closer at various factors having an influence on the measurement cycle data readouts and, as a consequence, to lay a foundation for a development a new penetrometric method of determining stress-strain parameters of rocks.
In this article it was shown that just before a main stage of the measurement cycle, a transitional stage could occur. It complicates a determination of the beginning of an useful set of measurement cycle data. This problem is widely known also in other static in situ methods of determining stress-strain parameters. Unfortunately, none of various known workouts of this problem were sufficiently adequate to the pre-treatment of the penetrometric measurement cycle results. Hence, a new method of determining the beginning of the useful set of pressure readouts has been developed. The proposed method takes into account an influence of an operational characteristics of the measuring device. This method is an essential part of a new pre-treatment procedure of the Pen206_18 measurement cycle’s pressure readouts.
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Bibliography

[1] A . Kidybiński, J. Gwiazda, Z. Hładysz, Ocena mechanicznych własności skał oraz stateczności górotworu hydraulicznym penetrometrem otworowym. Prace Głównego Instytutu Górnictwa, Seria Dodatkowa. Katowice (1976).
[2] R.E. Goodman, T.K. Van, F.E. Heuze, Measurement of Rock Deformability in Boreholes. In: Proceedings of the 10th U.S. Symposium on Rock Mechanics, University of Texas, Austin, TX, 523-555 (1970).
[3] AS TM D4971-02, Standard Test Method for Determining the In situ Modulus of Deformation of Rock Using the Diametrically Loaded 76-mm (3-in.) Borehole Jack. AS TM International, West Conshohocken, PA, (2002). DOI : https://doi.org/10.1520/D4971-16
[4] R. Pierszalik, S. Rajwa, A. Walentek, K. Bier, 2020. A Pen206 borehole jack suitability assessment for rock mass deformability determination. Arch. Min. Sci. 65 (3), 639-660 (2020). DOI : https://doi.org/10.24425/ams.2020.134135
[5] P.H.V. Nguyen, M. Rotkegel, H.D. Van, Analysis of Behaviour of the Steel Arch Support in the Geological and Mining Conditions of the Cam Pha Coal Basin, Vietnam. Arch. Min. Sci. 65 (3), 551-567 (2020). DOI : https://doi.org/10.24425/ams.2020.134134
[6] A . Walentek, T. Janoszek, S. Prusek, A. Wrana, Influence of longwall gateroad convergence on the process of mine ventilation network-model tests. International Journal of Mining Science and Technology 29, 585-590 (2019). DOI : https://doi.org/10.1016/j.ijmst.2019.06.013
[7] I RB Ogrodzieniec. Penetrometr otworowy typu Pen206. Dokumentacja techniczno-ruchowa + Załącznik A – pulpit Pen206E (2008).
[8] A . Nierobisz, Oznaczanie własności mechanicznych skał za pomocą hydraulicznego penetrometru otworowego nowej generacji. Górnictwo i Geoinżynieria 34 (2), 491-500 (2010).
[9] A . Nierobisz, J. Gawryś, K. Bier, Analiza konstrukcji hydraulicznego penetrometru otworowego i jego modernizacja dla zwiększenia zakresu pomiarowego. Przegląd Górniczy 72 (6), 1-15 (2016).
[10] F .E. Heuze, Estimating the Deformability and Strength of Rock Masses – In-Situ Tests, and Related Procedures. In: STRATCOM Advanced Concept Technology Demonstration (ACTD), Albuquerque (2003). DOI : https://doi.org/10.2172/15005085
[11] M. Rezaei, M. Ghafoori, R. Ajalloeian, Comparison between the In situ Tests’ Data and Empirical Equations for Estimation of Deformation Modulus of Rock Mass. Geosciences Research 1 (1), 47-59 (2016). DOI : https://doi.org/10.22606/gr.2016.11005
[12] A . Palmström, R. Singh, The deformation modulus of rock masses – comparisons between in situ tests and indirect estimates. Tunnelling and Underground Space Technology 16 (3), 115-131 (2001). DOI : https://doi.org/10.1016/S0886-7798(01)00038-4
[13] M. Bukowska, A. Kidybiński, Wpływ czynników naturalnych masywu skalnego na jego wytrzymałość określaną metodami penetrometryczną i laboratoryjną. Prace Naukowe Głównego Instytutu Górnictwa, Research reports mining and environment 1, 35-46 (2002).
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Authors and Affiliations

Rafał Pierszalik
1
ORCID: ORCID

  1. Central Mining Institute (GIG ), 1 Gwarków Sq., 40-166 Katowice, Poland
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Abstract

The purpose of the paper was to design geometric models of the movable connection made of brass for three different attachment options and three different loads. The numerical analysis of the mechanical properties, stresses, strains and displacements using the finite element method was carried out in SolidWorks 2020 and their comparative analysis was performed. The computer simulations performed will allow the boundary conditions that directly affect the mechanical properties of the engineering materials to be optimised.
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Authors and Affiliations

Amadeusz Dziwis
1
ORCID: ORCID
Tomasz Tański
1
ORCID: ORCID
Marek Sroka
1
ORCID: ORCID
Agata Śliwa
1
ORCID: ORCID
Rafał Dziwis
1
ORCID: ORCID

  1. Silesian University of Technology, Department of Engineering Materials and Biomaterials, 18A S. Konarskiego Str., 44-100 Gliwice, Poland
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Abstract

Reliable evaluation of stress-strain characteristics can be done only in the laboratory where boundary conditions with respect to stress and strain can be controlled. The most popular laboratory equipment is a triaxial apparatus. Unfortunately, standard version of triaxial apparatus can reliable measure strain not smaller than 0.1 %. Such accuracy does not allow to determine stiffness referred to strain range most often mobilized in situ i.e. 10-3 ÷ 10-1%, in which stiffness distribution is highly nonlinear. In order to overcome this problem fundamental modifications of standard triaxial apparatus should be done. The first one concerns construction of the cell. The second refers to method of measurement of vertical and horizontal deformation of a specimen. The paper compares three versions of triaxial equipment i.e. standard cell, the modified one and the cell with system of internal measurement of deformation. The comparison was made with respect to capability of stiffness measurement in strain range relevant for typical geotechnical applications. Examples of some test results are given, which are to illustrate an universal potential of the laboratory triaxial apparatus with proximity transducers capable to trace stress-strain response of soil in a reliable way.

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Authors and Affiliations

Mirosław J. Lipiński
Małgorzata K. Wdowska
Anna Wudzka
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Abstract

A DIRECT APPROACH to the problem of the separation of elastic strain energy in the case of generally anisotropic materials is described in the present work. It is based on a simple analysis of the strain tensor into a spherical and a deviatoric one. A definition of dilatational and distortional elastic strain densities is introduced, based on the consideration of the geometrical response of a material. Through the generalized Hooke's law, analytic expressions are obtained for the generally anisotropic materials. The present results coincide with the only available in the literature data for anisotropic materials with cubic symmetry. In addition, an application for transversally isotropic materials is presented.
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Authors and Affiliations

N. P. Andrianopoulos
V. C. Boulougouris
A. P. Iliopoulos
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Abstract

The paper shows the hybrid method of stress and strain distributions analysis. In the method, the results of displacement measurement were used as boundary conditions in the numerical analysis of the tested objects. The numerical analysis was performed with the use of the finite element method (FEM), whereas measurements of displacement were made by laser grating interferometry technique (moire interferometry). Examples of tests presented in the paper show good efficiency of the method in the analysis of stress and strain distribution in the areas of their heterogeneous distribution. Mutual completion of laser grating interferometry and finite element method makes it possible to exclude their disadvantages creating broader' possibilities for research impossible to achieve in separate use.
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Authors and Affiliations

Dariusz Boroński
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Abstract

Filler surface modification has become an essential approach to improve the compatibility problem between natural fillers and polymer matrices. However, there is limited work that concerns on this particular effect under dynamic loading conditions. Therefore, in this study, both untreated and treated low linear density polyethylene/rice husk composites were tested under static (0.001 s –1, 0.01 s –1 and 0.1 s –1) and dynamic loading rates (650 s –1, 900 s –1 and 1100 s –1) using universal testing machine and split Hopkinson pressure bar equipment, respectively. Rice husk filler was modified using silane coupling agents at four different concentrations (1, 3, 5 and 7% weight percentage of silane) at room temperature. This surface modification was experimentally proven by Fourier transform infrared and Field emission scanning electron microscopy. Results show that strength properties, stiffness properties and yield behaviour of treated composites were higher than untreated composites. Among the treated composites, the 5% silane weight percentage composite shows the optimum mechanical properties. Besides, the rate of sensitivity of both untreated and treated composites also shows great dependency on strain rate sensitivity with increasing strain rate. On the other hand, the thermal activation volume shows contrary trend. For fracture surface analysis, the results show that the treated LLDPE/RH composites experienced less permanent deformation as compared to untreated LLDPE/RH composites. Besides, at dynamic loading, the fracture surface analysis of the treated composites showed good attachment between RH and LLDPE.
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Authors and Affiliations

Mohd Firdaus Omar
1 2
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID
Sam Sung Ting
1 2
ORCID: ORCID
B. Jeż
3
ORCID: ORCID
M. Nabiałek
3
ORCID: ORCID
Hazizan Md Akil
4
ORCID: ORCID
Nik Noriman Zulkepli
1
ORCID: ORCID
Shayfull Zamree Abd Rahim
1
ORCID: ORCID
Azida Azmi
2
ORCID: ORCID

  1. Universiti Malaysia Perlis (UniMAP),Centre of Excellent Geopolymer & Green Technology (CeGeoGTech), Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Perlis, Malaysia
  3. Częstochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, 42-200 Częstochowa, Poland
  4. Universiti Sains Malaysia, School of Materials and Mineral Resources Engineering, Pulau Pinang, Malaysia
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Abstract

The present research deals with the effect of pre-strain on the hydrogen embrittlement behavior of intercritically annealed medium-Mn steels. A slow strain-rate tensile test was conducted after hydrogen charging by an electrochemical permeation method. Based on EBSD and XRD analysis results, the microstructure was composed of martensite and retained austenite of which fraction increased with an increase in the intercritical annealing temperature. The tensile test results showed that the steel with a higher fraction of retained austenite had relatively high hydrogen embrittlement resistance because the retained austenite acts as an irreversible hydrogen trap site. As the amount of pre-strain was increased, the hydrogen embrittlement resistance decreased notably due to an increase in the dislocation density and strain-induced martensite transformation.
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Authors and Affiliations

Sang-Gyu Kim
1
ORCID: ORCID
Young-Chul Yoon
1
ORCID: ORCID
Seok-Woo Ko
1
ORCID: ORCID
Byoungchul Hwang
1
ORCID: ORCID

  1. Seoul National University of Science and Technology, Department of Materials Science and Engineering, Seoul, 01811, Republic of Korea
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Abstract

Therapeutic and surgical applications of focused ultrasound require monitoring of local temperature rises induced inside tissues. From an economic and practical point of view ultrasonic imaging techniques seem to be the most suitable for the temperature control. This paper presents an implementation of the ultrasonic echoes displacement estimation technique for monitoring of local temperature rise in tissue during its heating by focused ultrasound The results of the estimation were compared to the temperature measured with thermocouple. The obtained results enable to evaluate the temperature fields induced in tissues by pulsed focused ultrasonic beams using non-invasive imaging ultrasound technique

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Authors and Affiliations

Piotr Karwat
Jerzy Litniewski
Tamara Kujawska
Wojciech Secomski
Kazimierz Krawczyk
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Abstract

Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.

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Authors and Affiliations

Sze-Wei Khoo
Saravanan Karuppanan
Ching-Seong Tan

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