Mustafa Soylak and Veysel Erturun
The purpose of this paper is to examine the effect of changing some riveting parameters on the riveting quality of a riveted aircraft structure. In this study, riveting was…
Abstract
Purpose
The purpose of this paper is to examine the effect of changing some riveting parameters on the riveting quality of a riveted aircraft structure. In this study, riveting was performed by applying friction under pressure.
Design/methodology/approach
During this friction riveting process, a feed of 3 mm/min was applied in the axial direction. Rotation speed values of 2,000, 2,200 and 2,400 rpm were selected. A 3-axis die milling machine was used to achieve the required positioning, pressing force and friction effect. 1.27 mm-thick Al 7075-T6 sheets and 2117-T3 forged rivets were used. The feed rate was applied at 1 mm/min in both tensile shear and cross-tensile tests.
Findings
The feasibility of friction riveting in 2117-T3 rivets was examined, it was shown that it could be done, and the most suitable rotation value for this process was determined.
Originality/value
Clamping force is one of the most important parameters for riveting quality. This study will contribute to a better understanding of the friction-forging riveting process along with the effects of riveting parameters. At the same time, it will lead to more research and expand the application of friction forging riveting to more structural connections.
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Adem Karci, Veysel Erturun, Eşref Çakir and Yakup Çam
This study aims to investigate the fatigue crack propagation behavior of SiC particle-reinforced 2124 Al alloy composites under constant amplitude axial loading at a stress ratio…
Abstract
Purpose
This study aims to investigate the fatigue crack propagation behavior of SiC particle-reinforced 2124 Al alloy composites under constant amplitude axial loading at a stress ratio of R = 0.1. For this purpose, it is performed experiments and comparatively analyze the results by producing 5, 10, 15 Vol.% SiCp-reinforced composites and unreinforced 2124 Al alloy billets with powder metallurgy (PM) production technique.
Design/methodology/approach
With the PM production technique, SiCp-reinforced composite and unreinforced 2124 Al alloy billets were produced at 5%, 10%, 15% volume ratios. After the produced billets were extruded and 5 mm thick plates were formed, tensile and fatigue crack propagation compact tensile (CT) samples were prepared. Optical microscope examinations were carried out to determine the microstructural properties of billet and samples. To determine the SiC particle–matrix interactions due to the composite microstructure, unlike the Al alloy, which affects the crack initiation life and crack propagation rate, detailed scanning electron microscopy (SEM) studies have been carried out.
Findings
Optical microscope examinations for the determination of the microstructural properties of billet and samples showed that although SiC particles were rarely clustered in the Al alloy matrix, they were generally homogeneously dispersed. Fatigue crack propagation rates were determined experimentally. While the highest crack initiation resistance was achieved at 5% SiC volume ratio, the slowest crack propagation rate in the stable crack propagation region was found in the unreinforced 2124 Al alloy. At volume ratios greater than 5%, the number of crack initiation cycles decreases and the propagation rate increases.
Originality/value
As a requirement of damage tolerance design, the fatigue crack propagation rate and fatigue behavior of materials to be used in high-tech vehicles such as aircraft structural parts should be well characterized. Therefore, safer use of these materials in critical structural parts becomes widespread. In this study, besides measuring fatigue crack propagation rates, the mechanisms causing crack acceleration or deceleration were determined by applying detailed SEM examinations.
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Göksel Behret, Oguzhan Sahin and Veysel Erturun
The purpose of this study is to investigate the effects of graphene nanoplates (GNPs), and alloying time on aluminum matrix composite. After mixing the powdered materials in the…
Abstract
Purpose
The purpose of this study is to investigate the effects of graphene nanoplates (GNPs), and alloying time on aluminum matrix composite. After mixing the powdered materials in the alloying device, solid samples were formed by sintering. It is thought that the effect of using such a mechanical mixer on GNPs will be investigated and this study will give a perspective on the composites that GNPs will make with Al and its alloys.
Design/methodology/approach
Mechanical alloying (MA) device capable of high-speed shaking (Spex) movement was used and alloying was performed by adding other metal powders into aluminum, which is the matrix material, with the addition of GNPs at three different rates and times. The crystal size and lattice stress parameters were calculated by obtaining the X-ray diffraction (XRD) graphics of the obtained powder mixtures.
Findings
The XRD graphs of the obtained powder mixtures showed that the Al peaks decreased when the MA time increased. When the scanning electron microscopy images of the powder mixtures were examined, it was observed that agglomeration occurred especially in 1 and 1.5 Wt.% graphene reinforced mixtures that were MA for 90 min. The increase in the amount of graphene had a negative effect on the homogeneous distribution. When the Vickers microhardness values of the samples were examined, the hardness value of all samples increased up to the MA time of 45 min, and decreased in the times over 45 min.
Originality/value
The use of GNPs in the mechanical alloying technique and the fact that this technique was performed on the Retsch MM 400 device, which is a Spex type mixer, shows the originality of the study in terms of time and material content.
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Mustafa Soylak and Veysel Erturun
The purpose of this study is to examine the effect of the rivet heads formed on the rivet strength by an experimental study if the bucking bar used in the forged rivet application…
Abstract
Purpose
The purpose of this study is to examine the effect of the rivet heads formed on the rivet strength by an experimental study if the bucking bar used in the forged rivet application includes gaps with different angles.
Design/methodology/approach
0.81 (0.032”) mm thick 2024 T3 sheets were used for the rivet joints. AD 2117 T4 forged rivets with a diameter of 3.2 mm (0.125″, 1/8″) are used for the joints. The special bucking bars (sidewall intersection angles of flat, 40°, 60° and 80°) were manufactured for the riveting process. To determine the mechanical properties of the prepared samples, cross-tension and tensile-shear tests were performed on a universal tensile testing machine.
Findings
As a result of the tensile-shear tests and cross-tensile, use of an 80 degrees bucking bar instead of rivets with a flat bucking bar increases the strength of the joint by approximately 20%. There is no systematic change in elongation. The results of tensile-shear and cross-tensile tests showed that forging rivets by special bucking bars have a significant effect on joint strength.
Originality/value
Increase in strength will require the use of thinner sheet metal and smaller rivets to achieve the same strength. This will reduce the weight of the aircraft. Weight reduction also means less fuel consumption and more economical flight. This increase in strength is a very important scientific achievement.
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Veysel Erturun and Durmuş Odabaş
The purpose of this study is to investigate the microstructure of fretting wear behavior in 6061-T6 aluminum alloy. The fretting wear of blind riveted lap joints of 6061-T6…
Abstract
Purpose
The purpose of this study is to investigate the microstructure of fretting wear behavior in 6061-T6 aluminum alloy. The fretting wear of blind riveted lap joints of 6061-T6 aluminum alloy plates, which are widely used in aircraft construction, was investigated. Fretting damages were investigated between the contact surface of the plates and between the plate and the rivet contact surface.
Design/methodology/approach
Experiments were carried out using a computer controlled Instron testing machine with 200 kN static and 100 kN dynamic load capacity. Max package computer program was used for the control of the experiments. Fretting scars, width of wear scars, microstructure was investigated by metallographic techniques and scanning electron microscopy.
Findings
It was found that fretting damages were occurred between the plates contacting surface and between the plate and rivet contact surface. As load and cycles increased, fretting scars increased. Fretting wear initially begins with metal-to-metal contact. Then, the formed metallic wear particles are hardened by oxidation. These hard particles spread between surfaces, causing three-body fretting wear. Fretting wear surface width increases with increasing load and number of cycles.
Originality/value
The useful life of many tribological joints is limited by wear or deterioration of the fretting components due to fretting by oscillating relative displacements of the friction surfaces. Such displacements are caused by vibrations, reciprocating motion, periodic bending or twisting of the mating component, etc. Fretting also tangibly reduces the surface layer quality and produces increased surface roughness, micropits, subsurface microphone.
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Veysel Erturun and Eyyup Ozbay
The purpose of this study is AlZn-based produced by high speed mechanical alloying method to investigate the effect of Zn amount on the composite material, Al-Zn-Mg-Cu-SiC…
Abstract
Purpose
The purpose of this study is AlZn-based produced by high speed mechanical alloying method to investigate the effect of Zn amount on the composite material, Al-Zn-Mg-Cu-SiC composite material billets are obtained by sintering.
Design/methodology/approach
Mechanical alloying, X-ray diffraction analysis (XRD) graphics, sintering, polishing, scanning electron microscopy and energy dispersive X-ray analyzer (EDX) images and micro hardness tests were applied, respectively.
Findings
In the XRD analysis results, it was observed that the Al peak height decreased as the alloying time increased. When the samples sintered for 90 min are examined, it can be clearly seen that the hardness increases as the Zn ratio increases. EDX analysis results also support XRD results.
Originality/value
Increase in strength will require the use of thinner sheet metal and smaller rivets to achieve the same strength. This will reduce the weight of the aircraft. Weight reduction also means less fuel consumption and more economical flight. This increase in strength is a very important scientific achievement.
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Mustafa Soylak and Veysel Erturun
The purpose of this study is to investigate how the sloping head fault in solid riveting affects the strength of the joint and to develop an efficient system for the solution of…
Abstract
Purpose
The purpose of this study is to investigate how the sloping head fault in solid riveting affects the strength of the joint and to develop an efficient system for the solution of the problem.
Design/methodology/approach
For rivet joints, 1.2-mm thick 2024-T3 plates were used. AD 2117 T4 solid rivets with a diameter of 3.2 mm were chosen for the joints. A new riveting mechanism has been created unmatched in the literature for solid rivets. In the riveting process, the bucking bar surface is positioned at a right angle to the riveting process axis. Alternative 5°, 10° and 15° fault angles were obtained. During the riveting process, a total of eight different test samples were produced, four for each of the tension-shear and cross-tension joints, by making 0°, 5°, 10° and 15° angles to the bucking bar. To determine the mechanical properties of the prepared samples, cross-tensile and linear tensile-shear tests were performed on a universal tensile testing machine. Special apparatus has been designed and produced for cross-tensile tests.
Findings
As a result of the tensile-shear tests, the decrease in the joint at 15° was 25% compared to the joint at 0°. There is no systematic change in elongation. As a result of the cross-tensile tests, there was a decrease in the cross-tensile force toward the sample with an error of 15°. Compared to the 0° joint, this decrease was approximately 14.5% in the 10° joint, while the decrease in the 15° faulty joint was 25.8%. It has been understood that riveting with an angle of 0° affects the strength very much.
Originality/value
A new riveting mechanism has been created unmatched in the literature for solid rivets. Experimentally, it has been shown that forged rivets can be made very economically and properly. It has been experimentally proven how much the rivet head shape formed in the wrong forged rivet application changes the result.