şerif çitil - Academia.edu (original) (raw)

Papers by şerif çitil

Journal of Adhesion, Dec 28, 2018

This study evaluates adhesively bonded pipes with curvedsurface lap joints subjected to internal ... more This study evaluates adhesively bonded pipes with curvedsurface lap joints subjected to internal pressure. To test the effects of curvilinear radii on the strength of the adhesive bond, steel pipes (St 37) with curved surfaces of the same lap length and different radii were bonded with the adhesive DP 810. Internal pressure was applied until failure and the mechanical behavior of the bonds was examined experimentally and numerically. Numerical analyses used Cohesive Zone Materials Models (bilinear, exponential, and mixed mode) to estimate the strength of the adhesive bonding. The parameters required for material models were determined experimentally and then experiments were run to verify the models with the finite elements. The results show that the curvature radius has considerable influence on failure pressure.

Euroasia journal of mathematics-engineering natural&medical sciences, Nov 25, 2021

In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive und... more In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive under torsion were investigated by considering different overlap lengths and curvilinear radii. For this purpose, St-37 galvanized steel pipes with ØD = 21.3 mm outer and Ød = 15.9 mm inner diameters were modeled in three dimensions by creating 8, 10, 12 mm overlapping lengths in male and female form and 30, 40 and 50 mm curvilinear radii on the forehead regions. Numerical analyzes of the created models were performed in the ANSYS Workbench program, and samples with an overlap length of 10 mm were prepared on the CNC (Computer Numerical Control) bench to verify the numerical analysis. The prepared male and female specimens were joined using an acrylic-based DP810 structural adhesive resistant to humid environments, curable at room temperature, and validation experiments were carried out. After the study, obtained numerical and experimental data showed that pipe lap joints subjected to torsional moment with the same lap length but different curvilinear radius have been observed to vary significantly in the amount of load they carry. In addition, as the overlap length increased, the amount of load they carried increased. Also, in this study was compared by performing stress analyzes according to the overlap length and radii of curvature.

Materialwissenschaft Und Werkstofftechnik, May 17, 2016

The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Remov... more The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Removal of damaged pipes with new ones gives rise to major disruption during operation. This causes loss of time and cost. This study aims to prevent crack propagation and to obtain fast repair in damaged area, at the beginning of the damage. Repair of small cracks in steel pipes using composite patches has been studied in this work. The aim of the study is to repair small cracks less than 8 mm length. For this purpose, holes with 8 mm diameters were drilled in 170 mm long pipes and composite patches with 2, 2.6 and 3.2 mm thickness and 35, 40 and 45 mm overlap lengths with 60, 90 and 120 o overlap angles were attached with an adhesive of 0.2 mm thickness. The repaired pipes were subjected to internal pressure until damage occurred. A finite element model was developed and the numerical results were verified based on experiments. The repair of steel pipe with adhesive bonding was successfully achieved under high pressure with composite patches. The results show that the increase in overlap angle results in an increased surface area, and consequently an increase in failure load. Furthermore, the failure load increased with an increase in patch thickness. Additionally, it is seen that the failure load does not change significantly with increasing patch thickness.

MP MATERIALPRUEFUNG - MP MATERIALS TESTING, Jul 1, 2021

Factors such as the surface geometry of a joint, the direction of the applied load, and the type ... more Factors such as the surface geometry of a joint, the direction of the applied load, and the type of adhesive used have a great influence on the strength of a joint in adhesive bonding. In adhesively bonded joints (ABJ), it is possible to improve surface geometry by forming various geometric surfaces. ABJs are not very resistant to peeling stress, thus requiring that a bonding model be analyzed according to the direction of the applied load to prevent peeling stress. In this study, a butt curved joint was prepared from aluminum plates (A2024-T3) to improve the surface geometry of the joint. The mechanical behavior of the joints in three-dimensions and subjected to bending were investigated depending on an increase in the curvature radius. The adhesive DP810 was used for bonding. The finite element analysis was performed in ANSYS and cohesive zone modeling was used for a simulation of the damage growth in the adhesive layer. The results of bilinear and exponential models were found to be more appropriate to the experimental results. When the radius of curvature increases, the damage load carried decreases in the butt curved lap joints. It was seen that decreases in the curvature radius significantly decrease normal stress.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Jun 25, 2019

In this study, curved lap joints were designed, particularly for the cases in which configuration... more In this study, curved lap joints were designed, particularly for the cases in which configuration or aerodynamic design was essential. Furthermore, the effect of the surface area on their strength was investigated. Hence, curved joint types were prepared on aluminum plates (A2024-T3) that are commonly used for aviation, and an angled joint type was created by increasing the radius of curvature. The created joint types were then joined by a two-component acrylic structural adhesive (DP410). The joint models were designed in three dimensions, and a finite element analysis was performed. Cohesive zone models (bilinear, exponential, and separation-distance) based on energy principles were used in the finite element analysis to estimate the strength of the adhesively bonded joint. The mechanical properties of the materials used in the joint models were experimentally determined to obtain the numerical solutions, which were validated by further experiments. The obtained results demonstrated that there was an increase in the surface area on which the adhesive was applied as the radius of curvature of the scarf lap joints decreased; however, this had an adverse effect on the failure load that was carried.

Pamukkale University Journal of Engineering Sciences, 2017

İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğr... more İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğrayan bu boruların onarılması son yıllarda hemen hemen her türlü alanda yaygın bir şekilde kullanılmakta olan yapıştırma bağlantılarıyla yapılmaktadır. Yapıştırma bağlantılarında birleştirilecek olan malzemeler aynı türden ya da farklı türden olabilmektedir. Yapıştırıcılar farklı malzemelerde farklı mukavemet değerleri sergileyebileceğinden dolayı hasara uğramış borunun yapıştırıcı ile tamir edilmesinde malzeme seçimi büyük önem taşımaktadır. Bu çalışmada, hasara uğramış galvanizli çelik boruların tamirinde kompozit, alüminyum ve çelik olmak üzere üç farklı yama malzemesi seçilerek yapıştırıcı üzerinde nasıl bir mekanik davranış sergileyeceği araştırılmıştır. İç basınca maruz boru tesisatlarında meydana gelen hasarlar, farklı yama malzemeleri kullanılarak tek tip yapıştırıcı ile birleştirilmiş nümerik ve deneysel olarak incelenmiştir. Bunun için galvanizli borular üzerine çatlak oluşturulmuş 7 (2 mm), 9 (2.6 mm) ve 11 (3.2 mm) tabakadan oluşan düz örgülü karbon fiber kompozit yamalar, alüminyum yamalar ve çelik yamalar iki bileşenli akrilik yapıştırıcı (DP810) ile birleştirilmiştir. Tamir edilen borulara iç basınç uygulanmış, yama kalınlığı yama bindirme açıları ve bindirme uzunluklarına bağlı olarak yapıştırıcı üzerinde etkileri incelenmiştir.

Proceedings in Engineering Mechanics, Nov 16, 2022

Adıyaman Üniversitesi mühendislik bilimleri dergisi, Apr 14, 2022

Bu çalışmada bindirme bölgesi geometrisi düz, açılı (scarf) ve eğrisel şeklinde tasarlanan, akril... more Bu çalışmada bindirme bölgesi geometrisi düz, açılı (scarf) ve eğrisel şeklinde tasarlanan, akrilik yapısal yapıştırıcı ile birleştirilmiş, çelik boru bağlantılarının, burulma yükü altındaki mekanik özellikleri incelenmiştir. Bunun için dış çapı (ØD) 21.3 mm, iç çapı (Ød) 15.9 mm, St-37 galvanizli çelik borular üzerine, erkek ve dişi şeklinde 10 mm bindirme uzunluğunda düz, açılı (scarf) ve eğrisel bindirme bağlantıları oluşturularak modellenmiştir. Doğrulama deneyleri için 10 mm bindirme uzunluğunda 30 mm eğrilik yarı çapında, eğrisel bindirme bağlantıları imal edilerek gerçekleştirilmiştir. Erkek ve dişi şeklinde hazırlanan numuneler, nemli ortama dayanıklı, oda sıcaklığında kürleşebilen akrilik esaslı DP810 yapısal yapıştırıcı kullanılarak birleştirilmiştir. Oluşturulan modellerin nümerik analizleri ANSYS Workbench programında yapılmıştır. Nümerik ve deneysel sonuçlar göstermiştir ki, numuneler lineerleştikçe yapıştırıcının uygulanmış olduğu yüzey alanı azalmış fakat taşımış oldukları burulma hasar yükünün arttığı gözlemlenmiştir.

Euroasia Journal of Mathematics, Engineering, Natural & Medical Sciences, 2021

In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive und... more In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive under torsion were investigated by considering different overlap lengths and curvilinear radii. For this purpose, St-37 galvanized steel pipes with ØD = 21.3 mm outer and Ød = 15.9 mm inner diameters were modeled in three dimensions by creating 8, 10, 12 mm overlapping lengths in male and female form and 30, 40 and 50 mm curvilinear radii on the forehead regions. Numerical analyzes of the created models were performed in the ANSYS Workbench program, and samples with an overlap length of 10 mm were prepared on the CNC (Computer Numerical Control) bench to verify the numerical analysis. The prepared male and female specimens were joined using an acrylic-based DP810 structural adhesive resistant to humid environments, curable at room temperature, and validation experiments were carried out. After the study, obtained numerical and experimental data showed that pipe lap joints subjected to torsi...

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2019

In this study, curved lap joints were designed, particularly for the cases in which configuration... more In this study, curved lap joints were designed, particularly for the cases in which configuration or aerodynamic design was essential. Furthermore, the effect of the surface area on their strength was investigated. Hence, curved joint types were prepared on aluminum plates (A2024-T3) that are commonly used for aviation, and an angled joint type was created by increasing the radius of curvature. The created joint types were then joined by a two-component acrylic structural adhesive (DP410). The joint models were designed in three dimensions, and a finite element analysis was performed. Cohesive zone models (bilinear, exponential, and separation-distance) based on energy principles were used in the finite element analysis to estimate the strength of the adhesively bonded joint. The mechanical properties of the materials used in the joint models were experimentally determined to obtain the numerical solutions, which were validated by further experiments. The obtained results demonstrat...

Advanced Structured Materials, 2017

Adhesives are commonly used in almost every sector of industry because of their high corrosion re... more Adhesives are commonly used in almost every sector of industry because of their high corrosion resistance, uniform stress distribution, and because they can bond similar or different materials. The surface geometry of bonded joints significantly affects strength behavior since it produces different stress conditions. Therefore, it is important to select an appropriate joint type. Using today’s technology, it is possible to increase the surface area of a bonded joint with different geometries with the same overlap length. In this study, an attempt was made to develop new joint types with different surface geometries that could be alternatives to conventional joints. New joint types were joined with acrylic structural adhesive and were subjected to tensile load. Models were created with finite elements to investigate the effects of the different joints on the strength. The tests showed that the lap joints withstood greater load with improved surface geometry.

Materialwissenschaft und Werkstofftechnik, 2016

The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Remov... more The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Removal of damaged pipes with new ones gives rise to major disruption during operation. This causes loss of time and cost. This study aims to prevent crack propagation and to obtain fast repair in damaged area, at the beginning of the damage. Repair of small cracks in steel pipes using composite patches has been studied in this work. The aim of the study is to repair small cracks less than 8 mm length. For this purpose, holes with 8 mm diameters were drilled in 170 mm long pipes and composite patches with 2, 2.6 and 3.2 mm thickness and 35, 40 and 45 mm overlap lengths with 60, 90 and 120° overlap angles were attached with an adhesive of 0.2 mm thickness. The repaired pipes were subjected to internal pressure until damage occurred. A finite element model was developed and the numerical results were verified based on experiments. The repair of steel pipe with adhesive bonding was successfully ...

The Journal of Adhesion, 2015

ABSTRACT Accidents in the industry, especially in the field of aerospace, are quite common. Damag... more ABSTRACT Accidents in the industry, especially in the field of aerospace, are quite common. Damages like tears cracks and holes occur especially when small sand particles present in the airfield collide with the body and wings of an airplane during takeoff and landing. This torn, cracked, or pierced region should be repaired gently. Damaged parts are frequently small regions for which repair is more suitable than complete replacement as workmanship; cost and time are an important concept in today’s world. A gap occurs between the patches if double-bonded patches are used in the repair of the damaged parts. In this study, the region between patches in a joint with and without intermediate parts was modeled and its effect on strength was examined numerically and experimentally. The effects of patch thickness, overlap length, adherent thickness, and gap length on the strength of the joints with and without intermediate part was compared. The results show that the intermediate part does not have any influence on the strength of the lap joint such that double strap joints without intermediate part have higher failure load. Additionally, it is seen that the failure load decreased with increasing patch thickness and increased with the thickness of the adherent.

Pamukkale University Journal of Engineering Sciences, 2017

İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğr... more İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğrayan bu boruların onarılması son yıllarda hemen hemen her türlü alanda yaygın bir şekilde kullanılmakta olan yapıştırma bağlantılarıyla yapılmaktadır. Yapıştırma bağlantılarında birleştirilecek olan malzemeler aynı türden ya da farklı türden olabilmektedir. Yapıştırıcılar farklı malzemelerde farklı mukavemet değerleri sergileyebileceğinden dolayı hasara uğramış borunun yapıştırıcı ile tamir edilmesinde malzeme seçimi büyük önem taşımaktadır. Bu çalışmada, hasara uğramış galvanizli çelik boruların tamirinde kompozit, alüminyum ve çelik olmak üzere üç farklı yama malzemesi seçilerek yapıştırıcı üzerinde nasıl bir mekanik davranış sergileyeceği araştırılmıştır. İç basınca maruz boru tesisatlarında meydana gelen hasarlar, farklı yama malzemeleri kullanılarak tek tip yapıştırıcı ile birleştirilmiş nümerik ve deneysel olarak incelenmiştir. Bunun için galvanizli borular üzerine çatlak oluşturulmuş 7 (2 mm), 9 (2.6 mm) ve 11 (3.2 mm) tabakadan oluşan düz örgülü karbon fiber kompozit yamalar, alüminyum yamalar ve çelik yamalar iki bileşenli akrilik yapıştırıcı (DP810) ile birleştirilmiştir. Tamir edilen borulara iç basınç uygulanmış, yama kalınlığı yama bindirme açıları ve bindirme uzunluklarına bağlı olarak yapıştırıcı üzerinde etkileri incelenmiştir.

Ic basinca maruz borular sicaklik ve basincin degismesi sonucunda hasara ugramaktadir. Hasara ugr... more Ic basinca maruz borular sicaklik ve basincin degismesi sonucunda hasara ugramaktadir. Hasara ugrayan bu borularin onarilmasi son yillarda hemen hemen her turlu alanda yaygin bir sekilde kullanilmakta olan yapistirma baglantilariyla yapilmaktadir. Yapistirma baglantilarinda birlestirilecek olan malzemeler ayni turden ya da farkli turden olabilmektedir. Yapistiricilar farkli malzemelerde farkli mukavemet degerleri sergileyebileceginden dolayi hasara ugramis borunun yapistirici ile tamir edilmesinde malzeme secimi buyuk onem tasimaktadir. Bu calismada, hasara ugramis galvanizli celik borularin tamirinde kompozit, aluminyum ve celik olmak uzere uc farkli yama malzemesi secilerek yapistirici uzerinde nasil bir mekanik davranis sergileyecegi arastirilmistir. Ic basinca maruz boru tesisatlarinda meydana gelen hasarlar, farkli yama malzemeleri kullanilarak tek tip yapistirici ile birlestirilmis numerik ve deneysel olarak incelenmistir. Bunun icin galvanizli borular uzerine catlak olusturul...

Yapistirma baglantilari endustride kullanilan geleneksel birlestirme tekniklerine iyi bir alterna... more Yapistirma baglantilari endustride kullanilan geleneksel birlestirme tekniklerine iyi bir alternatif olusturmaktadir. Duzgun gerilme dagilimi, sizdirmazlik, korozyon, farkli turden parcalari birlestirebilme ozellikleri ve daha bircok avantajlarindan dolayi yapistirma baglantilarina olan ilgi her gecen gun artmaktadir. Yapistirma baglantilarinin bircok avantaji olmasina ragmen soyulma gerilmelerine karsi mukavemetleri iyi degildir. Bu yuzden yapistirma baglantilarinda baglanti modeli buyuk onem arz etmektedir. Bu calismada, alin egrisel bindirme baglantisi ile duz bindirme baglantisi olmak uzere iki tip baglanti modeli kullanilmistir. Bu baglanti modelleri aluminyum alasimli plakalar (A2024-T3) kullanilarak imal edilmis ve akrilik yapisal yapistirici (DP810) ile birlestirilmistir. Egrisel ust uste binme ve duz ust uste binme baglantilari cekme yukune maruz birakilmis ve sonuclar karsilastirilmistir. Sonlu elemanlar analizi icin uc boyutlu olarak baglanti modelleri olusturulmus ve ya...

Mechanics, 2019

In this study, the curved type joint model, which is an alternative to conventional joint models,... more In this study, the curved type joint model, which is an alternative to conventional joint models, was developed and subjected to three-point bending moment by increasing the radius of curvature of the joint. The radius of curvature of the curved lap joint under three-point bending moment was increased, and its effects on strength were investigated. Furthermore, a three-dimensional non-linear finite element analysis of the joint model was performed using the generalized Drucker-Prager yield criterion. Verification tests were performed to verify the numerical solutions obtained by the non-linear finite element method. For this purpose, curved surfaces with radii of r=100, 300, 500 mm were formed on AA 2024-T3 aluminum sheets with a thickness of 6.5 mm, and they were bonded with DP410 acrylic structural adhesive. In accordance with the numerical and experimental results, the radius of curvature was observed to have significant effects on damage load and stress distribution in curved la...

Endustrinin hemen hemen her sektorunde, korozyon dayanimi, sizdirmazlik ozelligi, duzgun gerilme ... more Endustrinin hemen hemen her sektorunde, korozyon dayanimi, sizdirmazlik ozelligi, duzgun gerilme dagilimi, benzer veya farkli malzemeleri birlestirebilir olmasindan dolayi yapistiricilar yaygin bir sekilde kullanilmaktadir. Yapistirici ile birlestirmede malzemeye bagli olarak uygun bir yapistiricinin secilmesi oldukca onemlidir. Yapisma mekanizmasi, malzemelerin mekanik ozelliklerine bagli olarak farkli degerler gostermektedir. Bu calismada egrisel yuzeyli tek tesirli bindirme baglantilarinda farkli turden malzeme kullanilarak yapistirma baglantisinin mukavemet uzerine etkileri incelenmistir. Bu calismada cekme yukune maruz egrisel yuzeyli bindirme baglantilarinda ayni turden (Tip-I, AA2024-T3- AA2024-T3) ve farkli turden (Tip-II, AA2024-T3-ST37) yapistirma baglanti modeli olusturularak deneysel ve numerik olarak arastirilmasi yapilmistir. Egrisel bindirme baglantilarina cekme yuku uygulanarak baglantinin mukavemeti uzerinde etkileri arastirilmistir. Ayrica Tip-I ve Tip-II yapistirm...

Adhesive bonding is an excellent alternative to traditional joining techniques such as welding, r... more Adhesive bonding is an excellent alternative to traditional joining techniques such as welding, riveting, and is commonly used in almost every sector of the industry. However, there are many factors that have to be accounted for during joint design to accurately predict strength of the joint. One of these is the design of adhesively bonded joints. The objective of this work is to study the influence of curvature on strength of adhesively bonded curved-lap joints. For that, different radii of curvature were introduced to the end zones of an aluminium sheet to which the adhesive is applied. Then, a scarf lap joint was obtained by increasing the radius of curvature for the same overlap length, and mechanical behaviour of curved and scarf lap joints was studied experimentally. Additionally, in the analyses, the Extended Drucker-Prager material model was used and to verify the finite element model, experiments were carried out. The results show that thickness, overlap length and curvatur...

International Journal of Adhesion and Adhesives

Abstract Pipes can crack over time, particularly in areas with pipefittings and joints subject to... more Abstract Pipes can crack over time, particularly in areas with pipefittings and joints subject to high pressure and unsteady temperatures. Repair of these cracks requires labour, time, and expense and the cracked pipes are currently repaired with two methods. The first method is cutting out the damaged section of the pipe and adding an additional joint, which requires much time and labour. The second method is replacing the damaged pipe, which requires expensive materials. The aim of this study is to propose an alternative method that reduces or eliminates the use of labour, time, and materials, in order to quickly re-activate pipelines. For this purpose, the cracked steel pipes were repaired by using an adhesive, and the mechanical behaviours of the repaired pipes were investigated experimentally and numerically. In the first step of the study, artificial cracks were created on the pipes and the cracked pipes were repaired using adhesive and galvanized steel patches with different overlap lengths, overlap angles and thicknesses. Then, the repaired pipes were subjected to internal pressure in order to evaluate the effects of patch thickness, overlap angle and overlap length on the joint strength. Finally, the numerical analyses and experimental results show that the variation of the patch thickness, overlap length and overlap angle will change the stress distributions and strength of the adhesively repaired pipes.

Journal of Adhesion, Dec 28, 2018

This study evaluates adhesively bonded pipes with curvedsurface lap joints subjected to internal ... more This study evaluates adhesively bonded pipes with curvedsurface lap joints subjected to internal pressure. To test the effects of curvilinear radii on the strength of the adhesive bond, steel pipes (St 37) with curved surfaces of the same lap length and different radii were bonded with the adhesive DP 810. Internal pressure was applied until failure and the mechanical behavior of the bonds was examined experimentally and numerically. Numerical analyses used Cohesive Zone Materials Models (bilinear, exponential, and mixed mode) to estimate the strength of the adhesive bonding. The parameters required for material models were determined experimentally and then experiments were run to verify the models with the finite elements. The results show that the curvature radius has considerable influence on failure pressure.

Euroasia journal of mathematics-engineering natural&medical sciences, Nov 25, 2021

In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive und... more In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive under torsion were investigated by considering different overlap lengths and curvilinear radii. For this purpose, St-37 galvanized steel pipes with ØD = 21.3 mm outer and Ød = 15.9 mm inner diameters were modeled in three dimensions by creating 8, 10, 12 mm overlapping lengths in male and female form and 30, 40 and 50 mm curvilinear radii on the forehead regions. Numerical analyzes of the created models were performed in the ANSYS Workbench program, and samples with an overlap length of 10 mm were prepared on the CNC (Computer Numerical Control) bench to verify the numerical analysis. The prepared male and female specimens were joined using an acrylic-based DP810 structural adhesive resistant to humid environments, curable at room temperature, and validation experiments were carried out. After the study, obtained numerical and experimental data showed that pipe lap joints subjected to torsional moment with the same lap length but different curvilinear radius have been observed to vary significantly in the amount of load they carry. In addition, as the overlap length increased, the amount of load they carried increased. Also, in this study was compared by performing stress analyzes according to the overlap length and radii of curvature.

Materialwissenschaft Und Werkstofftechnik, May 17, 2016

The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Remov... more The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Removal of damaged pipes with new ones gives rise to major disruption during operation. This causes loss of time and cost. This study aims to prevent crack propagation and to obtain fast repair in damaged area, at the beginning of the damage. Repair of small cracks in steel pipes using composite patches has been studied in this work. The aim of the study is to repair small cracks less than 8 mm length. For this purpose, holes with 8 mm diameters were drilled in 170 mm long pipes and composite patches with 2, 2.6 and 3.2 mm thickness and 35, 40 and 45 mm overlap lengths with 60, 90 and 120 o overlap angles were attached with an adhesive of 0.2 mm thickness. The repaired pipes were subjected to internal pressure until damage occurred. A finite element model was developed and the numerical results were verified based on experiments. The repair of steel pipe with adhesive bonding was successfully achieved under high pressure with composite patches. The results show that the increase in overlap angle results in an increased surface area, and consequently an increase in failure load. Furthermore, the failure load increased with an increase in patch thickness. Additionally, it is seen that the failure load does not change significantly with increasing patch thickness.

MP MATERIALPRUEFUNG - MP MATERIALS TESTING, Jul 1, 2021

Factors such as the surface geometry of a joint, the direction of the applied load, and the type ... more Factors such as the surface geometry of a joint, the direction of the applied load, and the type of adhesive used have a great influence on the strength of a joint in adhesive bonding. In adhesively bonded joints (ABJ), it is possible to improve surface geometry by forming various geometric surfaces. ABJs are not very resistant to peeling stress, thus requiring that a bonding model be analyzed according to the direction of the applied load to prevent peeling stress. In this study, a butt curved joint was prepared from aluminum plates (A2024-T3) to improve the surface geometry of the joint. The mechanical behavior of the joints in three-dimensions and subjected to bending were investigated depending on an increase in the curvature radius. The adhesive DP810 was used for bonding. The finite element analysis was performed in ANSYS and cohesive zone modeling was used for a simulation of the damage growth in the adhesive layer. The results of bilinear and exponential models were found to be more appropriate to the experimental results. When the radius of curvature increases, the damage load carried decreases in the butt curved lap joints. It was seen that decreases in the curvature radius significantly decrease normal stress.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Jun 25, 2019

In this study, curved lap joints were designed, particularly for the cases in which configuration... more In this study, curved lap joints were designed, particularly for the cases in which configuration or aerodynamic design was essential. Furthermore, the effect of the surface area on their strength was investigated. Hence, curved joint types were prepared on aluminum plates (A2024-T3) that are commonly used for aviation, and an angled joint type was created by increasing the radius of curvature. The created joint types were then joined by a two-component acrylic structural adhesive (DP410). The joint models were designed in three dimensions, and a finite element analysis was performed. Cohesive zone models (bilinear, exponential, and separation-distance) based on energy principles were used in the finite element analysis to estimate the strength of the adhesively bonded joint. The mechanical properties of the materials used in the joint models were experimentally determined to obtain the numerical solutions, which were validated by further experiments. The obtained results demonstrated that there was an increase in the surface area on which the adhesive was applied as the radius of curvature of the scarf lap joints decreased; however, this had an adverse effect on the failure load that was carried.

Pamukkale University Journal of Engineering Sciences, 2017

İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğr... more İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğrayan bu boruların onarılması son yıllarda hemen hemen her türlü alanda yaygın bir şekilde kullanılmakta olan yapıştırma bağlantılarıyla yapılmaktadır. Yapıştırma bağlantılarında birleştirilecek olan malzemeler aynı türden ya da farklı türden olabilmektedir. Yapıştırıcılar farklı malzemelerde farklı mukavemet değerleri sergileyebileceğinden dolayı hasara uğramış borunun yapıştırıcı ile tamir edilmesinde malzeme seçimi büyük önem taşımaktadır. Bu çalışmada, hasara uğramış galvanizli çelik boruların tamirinde kompozit, alüminyum ve çelik olmak üzere üç farklı yama malzemesi seçilerek yapıştırıcı üzerinde nasıl bir mekanik davranış sergileyeceği araştırılmıştır. İç basınca maruz boru tesisatlarında meydana gelen hasarlar, farklı yama malzemeleri kullanılarak tek tip yapıştırıcı ile birleştirilmiş nümerik ve deneysel olarak incelenmiştir. Bunun için galvanizli borular üzerine çatlak oluşturulmuş 7 (2 mm), 9 (2.6 mm) ve 11 (3.2 mm) tabakadan oluşan düz örgülü karbon fiber kompozit yamalar, alüminyum yamalar ve çelik yamalar iki bileşenli akrilik yapıştırıcı (DP810) ile birleştirilmiştir. Tamir edilen borulara iç basınç uygulanmış, yama kalınlığı yama bindirme açıları ve bindirme uzunluklarına bağlı olarak yapıştırıcı üzerinde etkileri incelenmiştir.

Proceedings in Engineering Mechanics, Nov 16, 2022

Adıyaman Üniversitesi mühendislik bilimleri dergisi, Apr 14, 2022

Bu çalışmada bindirme bölgesi geometrisi düz, açılı (scarf) ve eğrisel şeklinde tasarlanan, akril... more Bu çalışmada bindirme bölgesi geometrisi düz, açılı (scarf) ve eğrisel şeklinde tasarlanan, akrilik yapısal yapıştırıcı ile birleştirilmiş, çelik boru bağlantılarının, burulma yükü altındaki mekanik özellikleri incelenmiştir. Bunun için dış çapı (ØD) 21.3 mm, iç çapı (Ød) 15.9 mm, St-37 galvanizli çelik borular üzerine, erkek ve dişi şeklinde 10 mm bindirme uzunluğunda düz, açılı (scarf) ve eğrisel bindirme bağlantıları oluşturularak modellenmiştir. Doğrulama deneyleri için 10 mm bindirme uzunluğunda 30 mm eğrilik yarı çapında, eğrisel bindirme bağlantıları imal edilerek gerçekleştirilmiştir. Erkek ve dişi şeklinde hazırlanan numuneler, nemli ortama dayanıklı, oda sıcaklığında kürleşebilen akrilik esaslı DP810 yapısal yapıştırıcı kullanılarak birleştirilmiştir. Oluşturulan modellerin nümerik analizleri ANSYS Workbench programında yapılmıştır. Nümerik ve deneysel sonuçlar göstermiştir ki, numuneler lineerleştikçe yapıştırıcının uygulanmış olduğu yüzey alanı azalmış fakat taşımış oldukları burulma hasar yükünün arttığı gözlemlenmiştir.

Euroasia Journal of Mathematics, Engineering, Natural & Medical Sciences, 2021

In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive und... more In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive under torsion were investigated by considering different overlap lengths and curvilinear radii. For this purpose, St-37 galvanized steel pipes with ØD = 21.3 mm outer and Ød = 15.9 mm inner diameters were modeled in three dimensions by creating 8, 10, 12 mm overlapping lengths in male and female form and 30, 40 and 50 mm curvilinear radii on the forehead regions. Numerical analyzes of the created models were performed in the ANSYS Workbench program, and samples with an overlap length of 10 mm were prepared on the CNC (Computer Numerical Control) bench to verify the numerical analysis. The prepared male and female specimens were joined using an acrylic-based DP810 structural adhesive resistant to humid environments, curable at room temperature, and validation experiments were carried out. After the study, obtained numerical and experimental data showed that pipe lap joints subjected to torsi...

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2019

In this study, curved lap joints were designed, particularly for the cases in which configuration... more In this study, curved lap joints were designed, particularly for the cases in which configuration or aerodynamic design was essential. Furthermore, the effect of the surface area on their strength was investigated. Hence, curved joint types were prepared on aluminum plates (A2024-T3) that are commonly used for aviation, and an angled joint type was created by increasing the radius of curvature. The created joint types were then joined by a two-component acrylic structural adhesive (DP410). The joint models were designed in three dimensions, and a finite element analysis was performed. Cohesive zone models (bilinear, exponential, and separation-distance) based on energy principles were used in the finite element analysis to estimate the strength of the adhesively bonded joint. The mechanical properties of the materials used in the joint models were experimentally determined to obtain the numerical solutions, which were validated by further experiments. The obtained results demonstrat...

Advanced Structured Materials, 2017

Adhesives are commonly used in almost every sector of industry because of their high corrosion re... more Adhesives are commonly used in almost every sector of industry because of their high corrosion resistance, uniform stress distribution, and because they can bond similar or different materials. The surface geometry of bonded joints significantly affects strength behavior since it produces different stress conditions. Therefore, it is important to select an appropriate joint type. Using today’s technology, it is possible to increase the surface area of a bonded joint with different geometries with the same overlap length. In this study, an attempt was made to develop new joint types with different surface geometries that could be alternatives to conventional joints. New joint types were joined with acrylic structural adhesive and were subjected to tensile load. Models were created with finite elements to investigate the effects of the different joints on the strength. The tests showed that the lap joints withstood greater load with improved surface geometry.

Materialwissenschaft und Werkstofftechnik, 2016

The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Remov... more The temperature change, internal pressure and corrosion are main reason of cracks in pipes. Removal of damaged pipes with new ones gives rise to major disruption during operation. This causes loss of time and cost. This study aims to prevent crack propagation and to obtain fast repair in damaged area, at the beginning of the damage. Repair of small cracks in steel pipes using composite patches has been studied in this work. The aim of the study is to repair small cracks less than 8 mm length. For this purpose, holes with 8 mm diameters were drilled in 170 mm long pipes and composite patches with 2, 2.6 and 3.2 mm thickness and 35, 40 and 45 mm overlap lengths with 60, 90 and 120° overlap angles were attached with an adhesive of 0.2 mm thickness. The repaired pipes were subjected to internal pressure until damage occurred. A finite element model was developed and the numerical results were verified based on experiments. The repair of steel pipe with adhesive bonding was successfully ...

The Journal of Adhesion, 2015

ABSTRACT Accidents in the industry, especially in the field of aerospace, are quite common. Damag... more ABSTRACT Accidents in the industry, especially in the field of aerospace, are quite common. Damages like tears cracks and holes occur especially when small sand particles present in the airfield collide with the body and wings of an airplane during takeoff and landing. This torn, cracked, or pierced region should be repaired gently. Damaged parts are frequently small regions for which repair is more suitable than complete replacement as workmanship; cost and time are an important concept in today’s world. A gap occurs between the patches if double-bonded patches are used in the repair of the damaged parts. In this study, the region between patches in a joint with and without intermediate parts was modeled and its effect on strength was examined numerically and experimentally. The effects of patch thickness, overlap length, adherent thickness, and gap length on the strength of the joints with and without intermediate part was compared. The results show that the intermediate part does not have any influence on the strength of the lap joint such that double strap joints without intermediate part have higher failure load. Additionally, it is seen that the failure load decreased with increasing patch thickness and increased with the thickness of the adherent.

Pamukkale University Journal of Engineering Sciences, 2017

İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğr... more İç basınca maruz borular sıcaklık ve basıncın değişmesi sonucunda hasara uğramaktadır. Hasara uğrayan bu boruların onarılması son yıllarda hemen hemen her türlü alanda yaygın bir şekilde kullanılmakta olan yapıştırma bağlantılarıyla yapılmaktadır. Yapıştırma bağlantılarında birleştirilecek olan malzemeler aynı türden ya da farklı türden olabilmektedir. Yapıştırıcılar farklı malzemelerde farklı mukavemet değerleri sergileyebileceğinden dolayı hasara uğramış borunun yapıştırıcı ile tamir edilmesinde malzeme seçimi büyük önem taşımaktadır. Bu çalışmada, hasara uğramış galvanizli çelik boruların tamirinde kompozit, alüminyum ve çelik olmak üzere üç farklı yama malzemesi seçilerek yapıştırıcı üzerinde nasıl bir mekanik davranış sergileyeceği araştırılmıştır. İç basınca maruz boru tesisatlarında meydana gelen hasarlar, farklı yama malzemeleri kullanılarak tek tip yapıştırıcı ile birleştirilmiş nümerik ve deneysel olarak incelenmiştir. Bunun için galvanizli borular üzerine çatlak oluşturulmuş 7 (2 mm), 9 (2.6 mm) ve 11 (3.2 mm) tabakadan oluşan düz örgülü karbon fiber kompozit yamalar, alüminyum yamalar ve çelik yamalar iki bileşenli akrilik yapıştırıcı (DP810) ile birleştirilmiştir. Tamir edilen borulara iç basınç uygulanmış, yama kalınlığı yama bindirme açıları ve bindirme uzunluklarına bağlı olarak yapıştırıcı üzerinde etkileri incelenmiştir.

Ic basinca maruz borular sicaklik ve basincin degismesi sonucunda hasara ugramaktadir. Hasara ugr... more Ic basinca maruz borular sicaklik ve basincin degismesi sonucunda hasara ugramaktadir. Hasara ugrayan bu borularin onarilmasi son yillarda hemen hemen her turlu alanda yaygin bir sekilde kullanilmakta olan yapistirma baglantilariyla yapilmaktadir. Yapistirma baglantilarinda birlestirilecek olan malzemeler ayni turden ya da farkli turden olabilmektedir. Yapistiricilar farkli malzemelerde farkli mukavemet degerleri sergileyebileceginden dolayi hasara ugramis borunun yapistirici ile tamir edilmesinde malzeme secimi buyuk onem tasimaktadir. Bu calismada, hasara ugramis galvanizli celik borularin tamirinde kompozit, aluminyum ve celik olmak uzere uc farkli yama malzemesi secilerek yapistirici uzerinde nasil bir mekanik davranis sergileyecegi arastirilmistir. Ic basinca maruz boru tesisatlarinda meydana gelen hasarlar, farkli yama malzemeleri kullanilarak tek tip yapistirici ile birlestirilmis numerik ve deneysel olarak incelenmistir. Bunun icin galvanizli borular uzerine catlak olusturul...

Yapistirma baglantilari endustride kullanilan geleneksel birlestirme tekniklerine iyi bir alterna... more Yapistirma baglantilari endustride kullanilan geleneksel birlestirme tekniklerine iyi bir alternatif olusturmaktadir. Duzgun gerilme dagilimi, sizdirmazlik, korozyon, farkli turden parcalari birlestirebilme ozellikleri ve daha bircok avantajlarindan dolayi yapistirma baglantilarina olan ilgi her gecen gun artmaktadir. Yapistirma baglantilarinin bircok avantaji olmasina ragmen soyulma gerilmelerine karsi mukavemetleri iyi degildir. Bu yuzden yapistirma baglantilarinda baglanti modeli buyuk onem arz etmektedir. Bu calismada, alin egrisel bindirme baglantisi ile duz bindirme baglantisi olmak uzere iki tip baglanti modeli kullanilmistir. Bu baglanti modelleri aluminyum alasimli plakalar (A2024-T3) kullanilarak imal edilmis ve akrilik yapisal yapistirici (DP810) ile birlestirilmistir. Egrisel ust uste binme ve duz ust uste binme baglantilari cekme yukune maruz birakilmis ve sonuclar karsilastirilmistir. Sonlu elemanlar analizi icin uc boyutlu olarak baglanti modelleri olusturulmus ve ya...

Mechanics, 2019

In this study, the curved type joint model, which is an alternative to conventional joint models,... more In this study, the curved type joint model, which is an alternative to conventional joint models, was developed and subjected to three-point bending moment by increasing the radius of curvature of the joint. The radius of curvature of the curved lap joint under three-point bending moment was increased, and its effects on strength were investigated. Furthermore, a three-dimensional non-linear finite element analysis of the joint model was performed using the generalized Drucker-Prager yield criterion. Verification tests were performed to verify the numerical solutions obtained by the non-linear finite element method. For this purpose, curved surfaces with radii of r=100, 300, 500 mm were formed on AA 2024-T3 aluminum sheets with a thickness of 6.5 mm, and they were bonded with DP410 acrylic structural adhesive. In accordance with the numerical and experimental results, the radius of curvature was observed to have significant effects on damage load and stress distribution in curved la...

Endustrinin hemen hemen her sektorunde, korozyon dayanimi, sizdirmazlik ozelligi, duzgun gerilme ... more Endustrinin hemen hemen her sektorunde, korozyon dayanimi, sizdirmazlik ozelligi, duzgun gerilme dagilimi, benzer veya farkli malzemeleri birlestirebilir olmasindan dolayi yapistiricilar yaygin bir sekilde kullanilmaktadir. Yapistirici ile birlestirmede malzemeye bagli olarak uygun bir yapistiricinin secilmesi oldukca onemlidir. Yapisma mekanizmasi, malzemelerin mekanik ozelliklerine bagli olarak farkli degerler gostermektedir. Bu calismada egrisel yuzeyli tek tesirli bindirme baglantilarinda farkli turden malzeme kullanilarak yapistirma baglantisinin mukavemet uzerine etkileri incelenmistir. Bu calismada cekme yukune maruz egrisel yuzeyli bindirme baglantilarinda ayni turden (Tip-I, AA2024-T3- AA2024-T3) ve farkli turden (Tip-II, AA2024-T3-ST37) yapistirma baglanti modeli olusturularak deneysel ve numerik olarak arastirilmasi yapilmistir. Egrisel bindirme baglantilarina cekme yuku uygulanarak baglantinin mukavemeti uzerinde etkileri arastirilmistir. Ayrica Tip-I ve Tip-II yapistirm...

Adhesive bonding is an excellent alternative to traditional joining techniques such as welding, r... more Adhesive bonding is an excellent alternative to traditional joining techniques such as welding, riveting, and is commonly used in almost every sector of the industry. However, there are many factors that have to be accounted for during joint design to accurately predict strength of the joint. One of these is the design of adhesively bonded joints. The objective of this work is to study the influence of curvature on strength of adhesively bonded curved-lap joints. For that, different radii of curvature were introduced to the end zones of an aluminium sheet to which the adhesive is applied. Then, a scarf lap joint was obtained by increasing the radius of curvature for the same overlap length, and mechanical behaviour of curved and scarf lap joints was studied experimentally. Additionally, in the analyses, the Extended Drucker-Prager material model was used and to verify the finite element model, experiments were carried out. The results show that thickness, overlap length and curvatur...

International Journal of Adhesion and Adhesives

Abstract Pipes can crack over time, particularly in areas with pipefittings and joints subject to... more Abstract Pipes can crack over time, particularly in areas with pipefittings and joints subject to high pressure and unsteady temperatures. Repair of these cracks requires labour, time, and expense and the cracked pipes are currently repaired with two methods. The first method is cutting out the damaged section of the pipe and adding an additional joint, which requires much time and labour. The second method is replacing the damaged pipe, which requires expensive materials. The aim of this study is to propose an alternative method that reduces or eliminates the use of labour, time, and materials, in order to quickly re-activate pipelines. For this purpose, the cracked steel pipes were repaired by using an adhesive, and the mechanical behaviours of the repaired pipes were investigated experimentally and numerically. In the first step of the study, artificial cracks were created on the pipes and the cracked pipes were repaired using adhesive and galvanized steel patches with different overlap lengths, overlap angles and thicknesses. Then, the repaired pipes were subjected to internal pressure in order to evaluate the effects of patch thickness, overlap angle and overlap length on the joint strength. Finally, the numerical analyses and experimental results show that the variation of the patch thickness, overlap length and overlap angle will change the stress distributions and strength of the adhesively repaired pipes.