Keresés

Keresési eredmények

• Experimental Investigation on the Properties of Borneo Soft Soil Stabilized with Industrial Waste

  25-37

  Prasetia Irfan

  Hutagamissufardal Hutagamissufardal

  Jimmy Ahmad

  Ananda Muhammad Dhiya Khairi

  Megtekintések száma:

  225

  This research aims to investigate the physical and mechanical properties of soft soil stabilized using industrial wastes, namely fly ash and rice husk ash. For this purpose, 6 (six) variations in the composition of fly ash (F), lime (L), and rice husk ash (R) were prepared. The variations in sample composition are SFLR1 (F: 15%, L: 2.5%, R: 5%), SFLR2 (F: 20%, L: 2.5%, R: 5%), SFLR3 (F: 25%, L: 2.5%, R: 5%), SFLR4 (F: 15%, L: 5%, R: 10%), SFLR5 (F: 20%, L: 5%, R: 10%) and SFLR6 (F: 25%, L: 5%, R: 10%). Meanwhile, soft soil was obtained from Banjarmasin City in South Borneo. The sample's physical properties were analyzed using the Atterberg limit test. Moreover, the California Bearing Ratio (CBR) and direct share tests are conducted to assess the sample's mechanical properties. The research results can provide confidence that fly ash, lime, and rice husk ash have the potential to improve the physical and mechanical properties of Borneo soft soil. The results of the Atterberg limit test show that industrial wastes can lower the liquid limit and increase the plastic limit; thus, the soil plasticity index decreases. As for the CBR test results, the untreated soft soil bearing ratio value of 1.4% can be increased to 2.6% after being treated with industrial wastes. In addition, using industrial wastes also decreases the swelling of the soil. Moreover, it can be seen that greater use of fly ash can improve the mechanical properties of the soft soil. However, increasing the composition of lime and rice husk ash can reduce the mechanical properties of the soft soil. Based on the experimental results, it is proposed to use SFLR3 as soil stabilization mixtures.

• The Mechanical Properties of 3D Printed CuZn28 Brass Specimens with Different Orientations

  253-259

  Szakál Zoltán

  Kári-Horváth Attila

  Pataki Tamás

  Odrobina Miklós

  Megtekintések száma:

  238

  In this paper, the properties of CuZn28 brass raw material were presented. The 3D printed metal specimens are made from this material with different orientations. Their mechanical properties (tensile strength, yield strength) and elongation were investigated according to MSZ EN 6892-1: 2012 standard. The strength of the different printing directions is analyzed and it is determined which printing direction is the most favourable. Finally, the effect of the different printing directions upon the structure of the material is studied.

• Effect of the Flow Curve Determination on the Thinning of Drawn Parts

  16-25

  Kölüs Martin László

  Borbély Richárd

  Szőke Dániel Gyula

  Béres Gábor József

  Megtekintések száma:

  94

  This study presents the results of finite element simulations based on different variations of the flow curve of DC04 automotive thin sheet. The aim of our research is to investigate how different flow curve equations affect the variation of sheet thickness in cup drawing tests. In order to exclude other influencing factors in the experiment, both the sheet material and the geometric properties of the specimen, as well as the external state factors were considered to be the same in all cases. The finite element simulations were performed using Simufact 2021.1 software. Our results shows that there are no significant differences in wall thicknesses until we reach the zone of double necking, where essential differences are observed.

• The Effect of Sizes of the Cast Polyamide 6 Rods upon Tensile-Impact Strength

  21-24

  Odrobina Miklós

  Kalácska Gábor

  Keresztes Róbert

  Megtekintések száma:

  144

  We have studied the tensile-impact strength of the magnesium catalysed cast polyamide 6 (PA6) rods according to the EN ISO 8256:2004 standard. The purpose of our investigation was to follow: the mechanical properties of rods are mapped beside same casting technological process in case of different diameters. We have compared the received results with each other than have sought disparities. We examined cylindrical product (rod) in seven dimensional steps in diameter ranging from 40 mm to 300 mm. We have determined that the semi-finished products can be divided into two groups typically in case of their tensile-impact strengths in this size range. The tensile-impact strength is higher in case of the rods with a diameter of less than 100 mm and it is smaller in the larger dimension range. Therefore, the smallest tensile-impact strength can be established in case of the natural semifinished PA6 rods that each rod accomplishes independently of size. However, a range can be determined, which the tensile-impact strength values of product are separated according to the manufacturing size

• New Method for Dynamic Tribological Test of Engineering Polymers

  25-29

  Sarankó Ádám

  Keresztes Róbert

  Kalácska Gábor

  Megtekintések száma:

  134

  In this article, tribological tests of Polyamide 6 (PA 6), Ultra High Molecular Weight Polyethylene (UHMW PE) and Polyoxymethylene copolymer (POM C) by a new testing method is introduced. The tribometer used in the test is capable for pin-on-disc measuring within all possible layout known in tribology practice, otherwise can be modified into special model of fatigue sliding test. The pin was a specimen made from examined materials, always in contact with a rotating metal disc under a normal load, which is usually static. However, since vibration exists in every practical scene as an important phenomenon, for instance in turning process, we added vibration load into the test. The supplement load is generated by a special-designed vibrating machine. Then properties of examined materials can be studied more profoundly under vibration load. As a result, different value of friction coefficient in static and vibration load have been discovered and taken into comparison.

• Literature Overall of Fatigue Analysis Approaches of Vehicle Components Made of Rubber

  130-140

  Tomposné Szüle Veronika

  Megtekintések száma:

  168

  Generally, the most frequently used structural materials are metals which have high strength and stiffness. However, there are many cases when other important properties come to the front, as well as high deformation capacity with elastic behavior, high viscosity namely good damping effect. Due to its above mentioned properties, rubber is widely used in vehicle and automotive industry. Vehicle components made of rubber usually exhibit large deformations. Cyclic finite deformations generate temperature in hyperelastic materials. Furthermore it is necessary to take into consideration the effects of ambient temperature. The mechanical properties of rubber depend on temperature and temperature changes can accelerate chemical alteration processes which lead to the material deterioration and fatigue processes. Research on fatigue behavior and fatigue properties of rubber has a great significance for predicting fatigue life and improving durability of rubber products. There are several studies on the fatigue behavior of rubber-based materials, but there is less research in the fatigue life prediction considering the influence of temperature and temperature changes. First purpose of this paper is summarizing the influence of temperature and temperature changes on the fatigue behavior of rubber. The second purpose of this study is to provide an overview of the state of the art on the fatigue life prediction of rubber with primary focus on the different methods available for prediction of fatigue life under the influence of temperature and temperature changes.

• Thermoelastic Problems of Multilayered Spherical Pressure Vessels Subjected to Axisymmetric Loading

  106-115

  Gönczi Dávid

  Megtekintések száma:

  134

  This paper deals with the linear thermoelastic analysis of functionally graded multilayered spherical bodies subjected to constant mechanical and thermal loading. The temperature field is arbitrary function of the radial coordinate, the material properties and the radial body force vary according to power law functions along the radius of the sphere. An analytical method is presented to calculate the displacements and stresses within the multilayered spherical body. The method is expanded to tackle the problem of spherical bodies made from radially graded materials with temperature dependent material properties. The results are compared to finite element simulations and other methods.

• Linear elastic finite element investigation of titanium specimen produced by Additive Manufacturing

  85-91

  Szabó Dániel

  Megtekintések száma:

  88

  Nowadays orthopaedic implants are mainly fabricated from solid material (titanium alloy). The mechanical properties of these implants are much stronger than human bone tissue’s properties, and this leads to fixation problems and a short lifetime, but today these problems can be eliminated with the usage of metal additive manufacturing. The mechanical properties of the implants can be influenced on demand with the variation of the material structure using different sizes and types of unit cells for building up its structure.

• Mixing Power Requirement Determination in Agitated Drum Using Dimensional Analysis

  76-88

  Horváth Dániel

  Poós Tibor

  Megtekintések száma:

  170

  The mixing of granular materials in an agitated drum can be characterized by the dimensionless power equation. The equation was created by dimensional analysis, for which the parameters affecting the mixing power requirement were collected based on the literature. The most important of these are the rotational speed, the drum loading factor, the geometric and physical properties of the mixing drum and the granular materials.  The dimensionless power equation is used to estimate with reasonable accuracy the Power number within the given range of applicability , which has been validated by measurements. From the Power number, the mixing power requirement of the mixed granular material can be calculated, which can be used as operational data for selecting the mixing motor.

• Investigation of the Granulometric and Mechanical Properties of Inorganic Used Sand

  302-308

  Dargai Viktória

  Varga László

  Megtekintések száma:

  175

  This paper examines the use of a modified inorganic binder in metal-alloy casting. The results of investigations regarding the effect of reusing the used sand multiple times without reclamation. The technological properties of silica sand with inorganic binders were presented, two different temperatures were applied to make the used sands. After lump crushing the inorganic used sand was recycled in order to make a new sand mixture. Our work was focused on the effect of multiple usage of inorganic used sands on the mechanical and granulometric properties prepared with modified inorganic binder.

• Properties of Cellulose Sheets Modified with Potassium-Humate and Copper (II)-Sulfate

  276-285

  Tóth Annamária

  Halász Katalin

  Megtekintések száma:

  109

  Throughout our research we have made potassium-humate from brown coal of Dudar. With potassiumhumate and copper(II)-sulfate we made test sheets of linter cellulose fibers. The surface energy, surface wettability, CIE Lab color-coordinates changing, bending resistance and tensile strength of the produced test sheets has been examined. There was no big difference in the different samples during surface energy and wettability testing. Examination of mechanical properties suggests that potassium-humate content increases bending resistance of the test sheets. The bending resistance of samples increased by 32%, 100% and 336% compared to the control test sheets while adding potassium-humate.

• Structural Analysis of Carbon Fiber-reinforced Thermoset Composite

  36-46

  Barreiro Larissa

  Araújo Paulo

  Teles John

  Megtekintések száma:

  190

  Materials are usually stronger in fibrous form than in bulk form. Composites are made from bonding two materials, where the reinforcement contributes with the outstanding natural properties and the matrix supports the fibers by transferring the loads between them, besides protecting the fiber from the environment hazards. Consequently, creating a strong composite that can be used in various applications and situations. In this academic work it is going to be analyzed how the composite made from carbon fiber and epoxy thermoset matrix behaves in specific situations, by making them in two different manufacturing methods. In addition, the analysis is going to be made in the laboratories of the university and then compared with computer analysis. So, the first phase of this academic work is being presented and highlighted below.

• Rotational molding of plasma treated polyethylene/short glass fiber composites

  103-108

  Ghanem Zoya

  Sasidharan Sari P.

  Jenikova Zdenka

  Špatenka Petr

  Megtekintések száma:

  176

  Rotational molding is a manufacturing technique for producing 3D hollow parts by adding plastic powder to a shell-like mold and rotating the mold while heating it with the powder. In contrary to the injection molding all the process operates at atmospheric pressure which makes reinforcement of the rotomolded product difficult. In this paper plasma treated PE and short glass fibers were dry mixed and used to produce composites by rotational molding process and characterized in terms of morphology and mechanical properties.

• Effects of TIG Reheating on Duplex Stainless Steel Weld Microstructure

  295-302

  Varbai Balázs

  Tolnai Ferenc

  Májlinger Kornél

  Megtekintések száma:

  164

  Duplex stainless steels (DSS) gaining their excellent mechanical properties and corrosion resistance due to their austenitic-ferritic microstructure, ideally in the same amount. However, to keep this ideal phase ratio during arc welding is very difficult. Generally, the arc welding processes will result in more ferritic microstructure in the weld metal and in the heat affected zone, due to the rapid cooling. The ferritic microstructure can cause chromiumnitride precipitation, because the nitrogen solubility in ferrite phase is very low below 700 °C. These chromiumnitride precipitations can cause loss of corrosion resistance and mechanical properties. However, during subsequent reheating, the chromium-nitrides can dissolve and act as a secondary austenite nucleation site in the ferritic microstructure. In our research we welded DSS specimen autogenously, with tungsten inert gas welding using pure argon and 94 % argon + 6 % nitrogen as shielding gasses. In the first case the sub-sequent solid-state reheating caused 20 % increase in the austenite fraction of the weld metal but with the use of mixed shielding gas only 5 % increase.

• Hazai Ipari Hulladékok Innovatív Hasznosítási Lehetőségei Építőanyagipari Célra

  203-212

  Mucsi Gábor

  Szabó Roland

  Rácz Ádám

  Papné Halyag Nóra

  Nagy Gáborné Ambrus Mária

  Debreczeni Ákos

  Móricz Ferenc

  Kristály Ferenc

  Megtekintések száma:

  125

  A Miskolci Egyetem Műszaki Földtudományi Karán működő Fenntartható Természeti Erőforrás Gazdálkodás Kiválósági Központban elvégzett kutatások eredményei azt mutatják, hogy a megfelelő előkészítést alkalmazva és a körülményeket optimálva a hulladék alapanyagok eljárástechnikai jellemzőinek (szemcseméret eloszlás, fajlagos felület) megváltoztatásával az építőanyag termékek fizikai és mechanikai tulajdonságai (szilárdság, tömörség) javíthatók. Kutatásaink ugyanis kimutatták, hogy a kémiai aktiválás mellett a mechanikai aktiválás is egy igen hatékony eszköz a tulajdonságok szabályozására. Ez azonban  megváltoztatja nemcsak a termék fizikai, mechanikai, hanem a szerkezeti, ásványtani jellemzőit is, ezért ezen jellemzők meghatározása is kiemelten fontos.

• Combustors with Low Emission Levels for Aero Gas Turbine Engines

  503-514

  Guellouh Noureddine

  Szamosi Zoltán

  Siménfalvi Zoltán

  Megtekintések száma:

  411

  The aircrafts are responsible for emitting several types of pollutants, especially the pollutants in the form of NOX, CO2, CO, UHC, SOX and Particulate Matter PM (smoke/soot). The impact of aviation emissions on the global is well known, where these emissions modify the chemical and microphysical properties of the atmosphere resulting in changes of earth’s climate system, which can ultimate in critical changes in our planet fragile ecosystem, also the pollutants produced by aircraft engines cause many health problems. This is why the International Civil Aviation Organisation (ICAO) is seriously seeking to control the emission levels by issuing new standards during the successive meetings of the Committee on Aviation Environmental Protection CAEP (CAEP/01 in 1986, CAEP/2, CAEP/4, CAEP/6, CAEP/8, etc). The new regulations include more stringent standards aimed to reduce emission levels, this led to increased interest in low emission technologies. In this paper, a comprehensive review of low emissions combustion technologies for modern aero gas turbines is represented. The current low emission technologies include the high Technologies Readiness Level (TRL) including RQL, TAPS, DAC and LDI. Also, there are advanced technologies at lower TRL including LPP, ASC and VGC.

• Járművek menetdinamikai szimulációs lehetőségei AVL Cruise M környezetben

  743-748

  Nemes Dániel

  Pálfi Tibor

  Hajdu Sándor

  Megtekintések száma:

  250

  A járműdinamikai szimulációk készítésekor a legtöbb esetben szükségünk van egy szoftverre, amellyel meggyorsíthatjuk a modell készítését és szimulációját. Erre a célra számos program van a piacon, azonban ezek eltérő tudással és felhasználói felülettel rendelkeznek. Cikkünkben röviden bemutatjuk a piac egyik vezető járműszimulációs szoftverének használatát, az AVL Cruise M-et.

• Determination of Different Parameters to High Strength Steel Clinch Joints by FEA

  341-347

  Jónás Szabolcs

  Tisza Miklós

  Megtekintések száma:

  223

  In this article the clinched joints were analyzed by finite element method (FEA). The base materials were advanced high strength steels (DP 600, DP 800 and DP 1000). The model validation procedure was done by the DP 600 type of steel sheets; the other two types of steel were only simulated. The goal was to determine the geometrical properties of the joints with different strength steels. The FEA model was the same in every mechanical point of view therefore the results are comparable. The main geometrical parameters of the clinch joints are the neck thickness (tN), the undercut (C), the bottom thickness (tB) and the height of the protrusion (h); these values were compared.

• Micromechanical Model of Dry Friction Hybrid Polymer Composite Clutch Facings

  335-340

  Biczó Roland

  Kalácska Gábor

  Megtekintések száma:

  100

  Modelling the complex coupled thermomechanical and tribological contact of a dry friction clutch system between cast iron flywheel and scatter-wound hybrid composite clutch facing requires a thought through investigation of the friction material properties and behaviour. Challenges of the creation of a mechanical stiffness matrix for such a complex material are described in this paper along with simplification ideas and solutions.

• Neural Network Based Enveloping Model of Agricultural Tyre

  214-222

  Stojic Boris

  Megtekintések száma:

  87

  The vibration properties of agricultural tractor’s tyres significantly influence its response in terms of the exposure of the human operator to mechanical vibrations, which is still one of the key problems in the design and exploitation of tractors. The behaviour of the tyre in this sense is significantly influenced by the mechanism ofgeometric filtering of the short-wavelength unevenness of the unprepared ground mostly encountered by tractor during in-field operations. Herein, this aspect of tyre behaviour was studied with tyre rolling quasistatically over singular obstacle. Based on experimental results, neural network based model of tyre enveloping behaviour was developed. Main model properties are high computational efficiency, simplicity regarding number of input quantities and absence of the need for explicit parametrization etc. Main shortcomings of modelling approach used are high developing effort, labour-intensive experimental preparations and lack of flexibility regarding tyre design and operating parameters

• Conceptual Design of the Low-Cost Environmental Temperature Test Chamber System

  81-94

  Menyhárt József

  Szabolcsi Róbert

  Megtekintések száma:

  120

  Unmanned robots being remotely controlled or autonomous are spread worldwide and used in different purposes. Inhabited robots are brought very close to users and accessibility to these tools is very high, moreover, at very low costs. Regardless to emphasize the increasing popularity of these robots. However, any robot system being electrically driven and controlled has bottleneck in the amount of the electrical energy stored aboard in the battery packs. In other words, due to limited amount of the electrical energy available special issues related to use energy best way with maximum effectiveness are needed and considered. Additionally, the battery management system is needed to control the processes of the discharge and the charge ensuring technical data and parameters set by the manufacturer. This paper addresses robot applications in regions out of the calculated when special environmental testing is needed to confirm battery pack technical data. Among those of the environmental tests required the temperature test is in the focus of attention. The main idea and purpose of this paper is to set up new concept of the low-cost environmental temperature test chamber, to define its technical parameters and other properties needed for its preliminary design and prototype manufacturing.

• The Possibilities of Additive Manufacturing in Medical Use

  246-253

  Szabó Dániel

  Megtekintések száma:

  118

  Additive Manufacturing has been invented in 1981 at the University of Texas, and to this day it has grown to be the most versatile and promising manufacturing technology in the market, both the industry and health care system has noticed this. Additive Bio-Manufacturing (ABM) techniques, which can be used in health care, are highly in demand, and researches have been going on to make these technologies safer and even more versatile. For more utilization and versatility, special attention is required to develop new materials which can help in increasing the service life, bioactivity, cell growth along with the desired mechanical properties, and to find the right manufacturing parameters for creating optimal products. The aim of this review is to present the available main Additive Manufacturing technologies, and particularly the biomedical usability of Additive Manufacturing.

• HAZ Characterization of Automotive DP Steels by Physical Simulation

  478-487

  Sisodia Raghawendra

  Gáspár Marcell

  Guellouh Noureddine

  Megtekintések száma:

  191

  DP steels were extensively used in the vehicles industry due to its extraordinary combined properties of strength, ductility, formability and weldability which contributed great significance in reducing strength to weight ratio and CO2 emission. High strength steel i.e. DP steels (3 different grades) were experimentally investigated and thermophysically simulated using Gleeble 3500 simulator to determine softening and hardening in heat affected zone. Samples were heated to different peak temperatures (1350 °C, 950 °C, 775 °C and 650 °C), two cooling time (t8.5/5 = 5 s and 30 s) and Rykalin 2D model were selected. The hardness and microstructure of the specimens were tested and analysed. For longer cooling time (t8.5/5= 30 s), we observed that softening occurs in all grade of investigated DP steels to all sub-regions. But for shorter cooling time i.e. t8.5/5= 5 s the softening is higher in intercritical HAZ compared to other sub-regions for all the types of DP steel with short cooling time (t8.5/5 = 5 s). However, the hardening zone in the CGHAZ occurs when Tmax is 1350 ºC for DP600, DP800 & DP1000 steels but it is more prominent in DP800 as compared to others two steel grade.

• The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel

  286-294

  Tóth László

  Fábián Réka

  Megtekintések száma:

  276

  The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.

• PVC/LDPE Blends: Relationship Between Thermal/Mechanical Properties, Structure and Blend Behaviour

  162-165

  Román Krisztina

  Zsoldos Gabriella

  Megtekintések száma:

  194

  In this paper the effect of LDPE content in PVC foams are examined on the structure of both the foam and the LDPE. We attempt to understand how LDPE content affects the structure of PVC in blends and how it changes the glass-transition (Tg). These parameters often provide important information related to the overall macromolecular structure of the polymer blend. Thermal analytical techniques such as differential scanning calorimetry (DSC) often used to determine the structural transformation of samples. The effect of the miscibility and composition of the PVC/LDPE foam blends on the thermal stability were also investigated.