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In this study an analytical model for linear coupling between the two perpendicular transverse vibration modes in a tightened bolt is presented. The model shows an excellent fit with the experimental data suggesting that the coupling is dominantly linear. An experiment is performed to support the linearity claim. Two physical scenarios that could justify the theoretical model is given, one scenario involves asymmetric boundary stiffness and the other one measurements imperfection in location. This work is motivated by its application in structural health monitoring techniques, in particular those based on measuring transverse vibrations of bolts and other beam-like components.

Existing research on the competitive failure relationship, failure mechanism, and influencing factors of bolt loosening and fatigue under different preloads is insufficient. This study analyzes the competitive failure relationship between bolt loosening and fatigue under composite excitation through competitive failure tests of bolt loosening and fatigue under different preloads. The results indicated that the failure mode of the bolt is only related to the load ratio (R) and is unrelated to the initial preload and excitation amplitude, which only determine the failure life of the bolt. The small axial loads of composite excitation can restrain bolt failure, and the significant degree of this restraining effect is different for different preloads. Subsequently, a fracture analysis of the bolt was performed to verify the competitive failure relationship of the bolt from a microscopic perspective, and the competitive failure mechanism of the bolt was determined. Based on the findings, we propose a calculation equation for the optimal preload of 8.8 grade high-strength bolts that can serve as a reference for engineering applications.

This work introduces a new coupled topology optimization approach for a structural assembly. Considering several parts connected by bolts, the shape and topology of potentially each part, as well as the position and number of bolts are simultaneously optimized. The main ingredients of our optimization approach are the level-set method for structural optimization, a new notion of topological derivative of an idealized model of bolt in order to decide where it is advantageous to add a new bolt, coupled with a parametric gradient-based algorithm for its position optimization. Both idealized bolt and its topological derivative handle prestressed state complexity. Several 3d numerical test cases are performed to demonstrate the efficiency of the proposed strategy for mass minimization, considering Von Mises and fatigue constraints for the bolts and compliance constraint for the structure. In particular, a simplified but industrially representative example of an accessories bracket for car engines demonstrates significant benefits. Optimizing both the structure and its connections reduces the mass by 24% compared to classical "structure-only" optimization.

This study selects 3D printing to innovate traditional research approaches regarding bolting. Three bolts composed of different manufacturing materials—aluminum alloy (AL), die steel (DS) and stainless steel (SS)—are successfully 3D printed, and the desired geometric profile is achieved with high precision. Prior to printing, the digital file of the prototype (PT) bolt is obtained by a 3D laser scanning system. Afterwards, mechanical tensile tests, infrared thermography (IRT) tests and digital image correlation (DIC) tests are carried out. The mechanical testing results indicate that the peak strength of the DS bolt is approximately twice that of the PT bolt. The IRT results show that the maximum temperature on the surface of all bolts except the AL bolt increases as the load increases, and the minimum temperature on the bolt surface is barely impacted by loading. DIC indicates a feasible relationship between the load and strain for the PT bolt, AL bolt and DS bolt. Overall, the AL bolt is not suitable for replicating the PT bolt, whereas the DS bolt and SS bolt are suitable choices. The conclusions established in this study provide new measures for future research regarding laboratory bolting tests and even engineering bolting trials.

Structural health monitoring techniques based on vibration measurements have been receiving large attention in the last decades, including techniques for estimating bolted joint tightness and detecting loosened bolts. Due to the exposure of bolted joints to external forces, the bolts may loosen and therefore affect healthy functioning of the bolted structure. In this work a technique is proposed to estimate the level of bolt tightness and to quantify the tension based on the measured natural frequencies of the bolt, in particular the first transverse natural frequency. An experiment is performed on two structure specimens each clamped with a bolt of different length. The bolts bending vibrations are excited by impacting the bolts head along the transverse direction. The excited transverse natural frequencies are then recorded as the bolts are gradually tightened. The measured frequencies trends are explained by modeling the bolt as a pre-stressed one dimensional beam with elastic supports at both ends. The experimental results are reproduced using an analytical function that expresses the boundaries stiffness in terms of the bolt tension. The sensitivity of the measured bolt first transverse natural frequency demonstrates the potential of this frequency-based technique in estimating bolt tightness.

In the current European standards for design of timber structures, the issue of timber-to-timber joint type is addressed only to squared timber, which makes the pinpointing of the round timber bolted joints load carrying capacity near-unfeasible due to the insufficient support in the current standards. There have been made series of tests of round timber joints in different inclinations of the loading force and also the reference tests of squared timber joints to compare the behaviour of this type of joints. Mechanical behaviour of the round and the squared timber bolted joints was tested in the laboratory of the Faculty of Civil Engineering in Ostrava. This paper presents results of static tests in tension at an angle of 0 degrees, 90 degrees and 60 degrees to the grain of squared and round timber bolted joints. Load carrying capacity was determined according to the applicable standards and theories of fracture mechanics. The test results of laboratory tests were then compared with the results of theoretical calculations. Web of Science 39 61 56

Threaded fastener is one of the most common ways to join components. Having a method to test threaded fasteners is key when designing a joint and even more a nutrunner. A joint is often tightened by a torque applied on the head. The applied torque is equal to three quantities in the joint, the thread torque, the underhead torque and the clamp force. To measure these quantities are the propose of a friction test rig. A test rig was built last year to be able to do that in a flexible and effective way. But the test rig built last year does not have the possibility to measure the underhead torque. A new transducer is constructed to add that possibility. The transducer is constructed by using methods such as concept generation, strength calculations, FEM simulations and a comparison of sensors are made. An easy way to change the stiffness is also investigated but no possible solution could be found. Some modifications and trims are also done on the test rig and also a comparison with the older BLM rig. A validation is made of how good the rig perform is also done. The results shows in favour for the FTR but precise results is not possible to determine.

The stress concentration in the fillet under a bolt’s head is a critical issue for the fatigue life of this component. Remembering the variable notch radius solution observed in many biological structures to lower stress concentrations due to normal loads, this work proposes, examines and optimizes a double circular arc fillet, not re-entering the head. The work implements an ad hoc shape optimization procedure that combines a genetic algorithm (the particle swarm optimization) and a parametric, axisymmetric finite-element model of the bolt: by focusing on an M12 bolt, the analysis focuses on two issues: first, the optimization of the radius of each arc in the fillet; second, the optimization of the bolt’s head height and head’s diameter in combination with the fillet radiuses. By comparing the proposed solution with the fillet geometries for the bolt’s heads from the literature, it appears a noticeable stress reduction, about 14% lower than the standard circular fillet, combined with an easy manufacturing.

M8x100x1,25 – 6g 10.9 kalite cıvataların gevşeme hızları yapay sinir ağları yardımıyla tahmin edilmeye çalışılmıştır. İki farklı tipte kaplanmış cıvataların, beş farklı kilitleme boylarında, dört farklı kilitleme yüklerinde, iki farklı tipte kaplanmış somunlar ile tüm kombinasyonlarda bağlantıları yapılarak yanal yüklemeli titreşim testleri gerçekleştirilmiştir. Titreşim testleri sonucunda incelenen tüm parametrelerin gevşemeye olan etkilerine ulaşılmıştır. Test sonuçlarının %70'i; yapay sinir ağlarının eğitim verisi olarak kullanılmış, %30'u ise test ve doğrulama için kullanılmıştır. Performansları değerlendirilen yaklaşık 430.000 yapay sinir ağından en yüksek performansı gösteren ağ tespit edilmiştir. En yüksek performansı gösteren ağ, gerçek test sonuçlarına çok yakın, tatmin edici gevşeme hızları tahminleri yapmıştır. Yapılan tahminlerin ortalama kare hatası (MSE) 1,6652x10^(-5)'tir., prediction of loosening rates of M8x100x1,25 – 6g 10.9 bolts under the transverse loading vibration has been tried via artificial neural networks. The two different types of coated bolts with different clamping lengths, different clamping loads, different types of coated nuts fastened and transverse loading vibration tests were conducted in all combinations. In result of vibration tests, effects of all researched parameters to self-loosening were found out. 70% of test results were used for training data for artificial neural networks, 30% of test results were used for test and validation. Approximately, 430.000 neural networks' performances were evaluated and highest performance network was detected. The highest performance neural network predicted the loosening rates to real test results closely and satisfying. MSE (Mean Square Error) criteria of predictions is 1,6652x10^(-5).

Otomotiv sanayi birçok birleştirme tekniklerinin kullanıldığı bir endüstridir. Bu sektör de farklı ve aynı türdeki sacların birleştirilmesi işleminde kaynak ile birleştirme yöntemi sıklıkla kullanılmaktadır. En yaygın kaynak ile birleştirme yöntemi direnç (punta) kaynağı yöntemidir. Direnç kaynağında minimum 2 sac metal kaynak ile birleştirilir. Projeksiyon kaynağı ise direnç kaynağının alt kolu olup, somun veya cıvataların birleştirilmesinde kullanılmaktadır. Araç gövdesinde kaynak ile birleştirme yapılamayan ve belirli tork değerine sahip olması gereken noktalarda cıvata ve somun ile birleştirme yapılmaktadır. Yöntemin otomasyona uygunluğu, seri bir üretim yöntemi olması, çevre dostu ve temiz bir metot olması, işçi sağlığı ve emniyeti açısından risklerin az olması nedeniyle tercih edilen ve günümüzde de popülerliğini koruyan bir yöntemdir. Projeksiyon kaynağını belirleyen ana parametreler, kaynak akımı, kaynak zamanı, basınç ve malzeme türüdür. Bunların dışında kaynak makinasının tipi, parça kalınlığı, elektrot tipi gibi etkenlerde kaynak kalitesini etkilemektedir. Gelişen teknoloji ve değişen malzeme türleri, otomotiv endüstrisini alternatif parametre arayışlarına itmektedir. Malzeme mukavemetinin artması, kaynak kalitesini doğrudan etkilemekte ve standart sapması yüksek kalitesel sonuçlara neden olmaktadır. Bu çalışma da M6 cıvata kaynağında yaşanan varyasyon problemi incelenecek ve kaynak davranışına göre parametre optimizasyonu yapılacaktır. Anahtar Kelimeler: Birleştirme Teknikleri, Cıvata Kaynağı, Direnç Kaynağı, Projeksiyon Kaynağı. Many joining methods are being used in automotive industry. It's frequently used on joining of similar or dissimilar sheet metal parts in automotive industry. The most common joining method is resistence welding method. Minimum 2 sheet metals are joined in resistence welding. Projection welding which, is sub division of resistence welding, is used for joining of nut's and bolt's. At the point of which is not allowed to apply any welding methods or required certain torque, nut's and bolt's joining methods are often used in car body. The advantages of projection welding are as follows; it is rather clean and friendly process for environment, easy to automatisation and easily applicable method, less risk for operator healthy. Main parameters are welding current, welding time, pressure and material type is determine the quality of welding. Except those, type of welding machine, material thickness, electrode type are also effect quality of welding. Automotive industry is being forced to develope new parameters for catching new material trend. Due to hardness of material increasing, quality of spots have been effected directly. In this study, the varition problem of M6 bolt projection welding will be researched and paremeter optimization will be done.Keywords: Joining Methods, Bolt Welding, Resistence Welding, Projection Welding. 100

Bolted connections are applied in many aluminium structures. Stainless steel bolts are often preferred over carbon steel bolts in aluminium connections to prevent galvanic corrosion. However, current design standards and guidelines do not allow for using preloaded stainless steel bolts in slip resistant connections, mainly because of a lack of knowledge on the preload loss to be expected in these connections, and this limits the application field of this type of structure. This paper presents a combined empirical and analytical (i.e. mechanical) study into preload losses of stainless steel bolts in aluminium slip resistant connections caused by long-term effects (creep and relaxation), thermal expansion, and lateral contraction. It appears that stainless steel bolts can be applied in aluminium slip resistant connections, but a larger partial safety factor than standards currently prescribe is required for the slip resistance in ultimate limit state.

Bu çalışmada, titreşim altındaki cıvata bağlantılarında meydana gelen tork kayıpları incelenmiştir. Önce konu ilgili literatür araştırmaları yapılmış, daha önce yapılan çalışmalarda kullanılan yöntemler incelenmiştir. Daha önceki araştırmalarda kullanılan Junker Test Cihazı üzerinde durulmuş, bu test cihazına benzer fakat eksenel titreşimin yanında dikey yönde titreşim sağlayan bir cihazın yapılması öngörülmüştür. İstenilen test cihazının özellikleri belirlenmiş ve cihaz tasarlanıp üretilmiştir. Üretilen test cihazında çeşitli parametrelerde testler yapılmış ve sonuçlar analiz edilmiştir. Anahtar Kelimeler: cıvata, cıvata gevşemesi, cıvata sıkma torku In this study, the torque loss of bolted connections under vibration has been investigated.First, detailed literature search has been made and test methods of previous studies have been investigated.Junker Testing equipment which was used in previous studies, is considered but it is decided to make a new testing equipment which provides vertical vibration beside of axial vibration.Properties of desired testing equipment has been decided. Then, the equipment designed and produced.A series of tests have been performed with the new testing equipment and results have been reported.Key words: bolt, bolt nut loosening, bolt thightening torque 85

The paper deals with the assessment of the correct design methodology that allows selecting the appropriate screw (in terms of reference nominal diameter) to be used in high duty bolted joints. Some Standards or Guidelines are analysed and discussed although the most complete appears the VDI-2230 (February 2003); in many cases the simplifications adopted can only be effective in presence of steel screws clamped on steel plates (often considered as rigid in comparison to the screw) and by considering coefficients of friction which vary in a narrow range (0.15–0.20). Hence, the increasing use of lightweight materials in recent years (e.g. magnesium, aluminium and titanium), as well as design optimisations, is forcing the screw designers to perform an attentive selection of the most appropriate fastening connection. For these reasons, this contribution tries to give a compressed, but comprehensive and clearly structured view about the maximum equivalent stress acting on the bolt as a function of the actual joint parameters (e.g. ratio between tensile and shear forces acting on the joint, ratio between bolt and plates stiffness, effect of coefficient of friction, static or fatigue loads).

International audience; The fatigue behaviour of bolts under axial load has always been considered from the component point of view for which fatigue limit is usually taken equal to 50 MPa, and few results are available to designers for limited lifetimes. Here, we take up this problem from a material point of view using a local approach. For each case of fatigue testing, using finite‐element (FE) model of the bolt, we determine the stabilized local stress at the root of the first thread in contact with the nut. To characterize bolt behaviour with these numerical results, we use Dang Van multiaxial fatigue criterion for which we extend application to the medium fatigue life. These results can be correlated with the experimental numbers of cycles to failure to determine material parameters of the generalized criterion. Using statistical Gauss method, we can make lifetime predictions for any level of risk of failure. In addition, we propose an analytical model to rapidly determine the local stress condition from nominal loading data (mean stress and alternating stress). This model dispenses us from a new modelling if the bolt is stressed in the same manner as the bolts used for behaviour characterization. Using this model and the generalized criterion, it is extremely easy to make lifetime predictions whatever the risk considered.

A set of temperature-dependent friction coeffi- cients was developed to increase the accuracy of finite element (FE) simulations of cold bolt forging. The initially attained friction coefficients at different temperatures were calibrated with the iterations between the experimental and thermomechanical model extrusion test loads. The constant friction coefficient and the determined set of friction coef- ficients as function of temperature were then implemented to the simulations of the cold bolt-forging processes. Further calibrations and model validations were made based on the temperature measurements of the workpiece in the actual bolt-forging processes. To show the advantages of devel- oped temperature-dependent friction coefficients, the loads of four different bolt-forging processes were compared with the thermomechanical model loads calculated using the constant friction and temperature-dependent friction coeffi- cients. The modeling results indicated that the use of temperature-dependent friction coefficients in the FE simu- lations resulted in nearer temperature distributions and the loads of the workpiece during forging as compared with the use of a constant friction coefficient.

Bu çalışmada,yüksek dayanımlı cıvata malzemelerinden birisi olan 30MnB4 çeliğinin statik dayanım değerlerinin çeşitli ısıl işlem sıcaklıklarında nasıl değiştiği incelenmiştir.Temin edilen cıvata çeliğinden cıvatalar basılmış ve bu cıvatalar ısıl işleme tabi tutulduktan sonra çekme deneyine tabi tutulmuştur.Elde edilen değerler standart değerlerle karşılaştırıldıktan sonra cıvatanın kalitesi belirlenmiştir.Bu malzeme için hangi ısıl işlem sıcaklığında, hangi kalite cıvata elde edilebileceği belirlenmiş ve bunlar tablo haline getirilmiştir.Böylece yüksek dayanımlı cıvatalar hakkında daha önce eksikliği hissedilen bazı bilgiler literatüre kazandırılmıştır. This study, which is one of the high-strength bolts 30MnB4 steel materials of various heat treatment temperatures, the change in the static strength values were examined. pressed steel bolts and screws supplied bolt, after being subjected to heat treatment were subjected to tensile test.The values obtained were the quality of the bolt after comparison with standard values.This heat treatment temperature for the material which, which can be obtained quality bolts are determined and are tabulated.Thus, high-strength bolts lacking some information about earlier gained to literature. 97

Kompresör muhafazaları yüksek basınç ve sıcaklık altında çalışan ve motorçerçevelerine yük aktarımını sağlayan oldukça ince yapılardır. Bu sebeplemuhafazaların tasarımı pek çok parametrenin bir arada gözönünde bulundurulmasınıgerektirir ve en doğru konfigürasyonun seçilmesi büyük öneme sahiptir. Bu çalışmadaçeşitli konfigürasyonlar için sonlu elemanlar yöntemi ile analizler gerçekleştirilmiştir.Geometriler parametrik bir şekilde oluşturulmuş ve civata sayısı, kabuk kalınlığı, civataçapı, öngerilme yükü ve flanş boyutları ana parametreler olarak saptanmıştır. Sonuçlartoplam ağırlık ve yapısal dayanım baz alınarak değerlendirilerek gerilme, kaçaklar(sızıntı) ve ovalleşme gözönünde bulundurulmuştur.Anahtar kelimeler: Gaz Türbinli Motor, Kompresör, Kompresör Muhafazası, Doğrusalolmayan analiz, Civata, Önyük Compressor casings which are subject to high pressure and temperatures arevery thin elements and are responsible for transferring high engine loads to the frames.For this reason, in the design of the casings, a number of parameters should be takeninto account, and the selection of the most appropriate configuration is crucial. In thisstudy, finite element analyses are performed for various configurations. The geometriesare created in a parametric manner and the number of bolts, shell thickness, boltdiameter, preload, flange dimensions are selected as main design parameters. Overallweight and structural strength is evaluated considering the stress, the leakage and theovalizationKeywords: Gas Turbine Engine, Compressor, Compressor Casing, NonlinearAnalysis, Bolt, Preload 145

As the main form of structure assembly, the stability of bolt joint is directly related to the per- formance of spacecraft. This essay is used to analyze the cause of standard torque spanner which is not suitable to the tightening torque and summarized according to different operating conditions. Based on thorough analysis of fastening principles and principle of type serialization, a scheme of integrated L Lever is established. The re- sults of experimentation indicate that the scheme of integrated L Lever is reasonable along with the requirement of developing long-life and high-reliability spacecraft. Therefore, the stability of fasteners is greatly enhanced.

CİVATALI BAĞLANTILARDA BİRLEŞTİRİLEN ELEMANLARIN DİRENGENLİĞİNİN SONLU ELEMANLAR YÖNTEMİ VE YAPAY SİNİR AĞLARI SİSTEMİ İLE BELİRLENMESİ VE CİVATA TASARIMI (Doktora Tezi) Murat Tolga ÖZKAN GAZİ ÜNİVERSİTESİ FEN BİLİMLERİ ENSTİTÜSÜ Ağustos 2003 ÖZET Civatalı bağlantılardaki eleman direngenliğini (member stiffness) belirlemek için Sonlu Elemanlar Yöntemi kullanılarak, ANSYS paket programında 3 boyutlu olarak; cıvata çapı, delik çapı, baş altı çapı, eleman kalınlıkları tasarım parametrelerine bağlı olarak civatalı bağlantılar modellenmiştir. Bu modelde 3 mm lik vida delik çapından 30 mm lik vida delik çapına kadar değişik eleman kalınlıklarında ve değişik elastikiyet modülü ve Poisson oranlarında eleman direngenliği belirlenmiştir. İstenilen her çeşit ölçü ve malzeme değişikliğinde eleman direngenliğim belirlemek için sonlu elemanlarla elde edilen veriler basınç dağılım açısını da verebilecek şekilde yapay sinir ağı sistemlerine uygulanmıştır. Elde edilen sonuçlar literatür ile karşılaştırılmıştır. Visual Basic programında, yapay sinir ağlan sistemi kullanarak, değişken eksenel dış yük ve kesme yükü taşıyan civatalı bağlantılar için bir tasarım programı hazırlanmıştır. Program değişik çentik faktörlerini de yapay sinir ağları siteminden alarak civatalı bağlantı tasarımım gerçekleştirmektedir. Bilim Kodu : 708 Anahtar Kelimeler : Eleman Direngenliği, Sonlu Elemanlar Yöntemi, Civatalı Bağlantı, Yapay Sinir Ağı Sistemi Sayfa Adedi : 132 Tez Yöneticisi :Prof. Dr. Kürşad DÜNDAR Prof. Dr. Mahmut GÜLESİN n DETERMINATION OF MEMBER STIFFNESS OF ELEMENTS JOINTED BY BOLTS USING FINITE ELEMENT METHODS AND NEURAL NETWORK SYSTEM AND BOLT DESIGN (Ph.D Thesis) Murat Tolga ÖZKAN GAZI UNIVERSITY INSTUTE OF SCD2NCE AND TECHNOLOGY July 2003 ABSTRACT Bolted joints have been modelled in 3D, using Finite Element Method (FEM) in ANSYS program according to design parameters namely bolt diameter, screw hole diameter, bolt head diameter and element thickness in order to determine member stiffness in bolted joints. In these models, member stiffness was determined for various materials,thicknesses, modulus of elasticity, Poisson ratios and hole diameters ranging from 3 mm to 30 mm. The data obtained from FEM were applied to Neural Network System so that it gives the conical frustrum angle to determine member stiffness for various dimensions and materials. The results obtained were compared to the literature. A design program for bolted joints, carrying axial loading and shear loading status was prepared in Visual Basic program. The program provides bolted joint designs receiving stress concentration factor from Neural Network System. Bilim Kodu : 708 Anahtar Kelimeler : Member Stiffness, Finite Element Method, Bolted Joint, Neural Network System Sayfa Adedi : 132 Tez Yöneticisi :Prof. Kürşad DÜNDAR Prof. Mahmut GÜLESİN 132

IV ÖZET Bu çalışmada, eksenel yüklere maruz civatalarda üç boyutlu gerilme analizi yapılmıştır. Civata başlarında ve civata dişlerindeki gerilmeler incelenmiştir. Ci vatanın düzgün dairesel kesitli kısmından (dişsiz kısım) baş kısmına geçişte oluşturulan radyüs yarıçaplarına göre değişimleri incelenmiş ve gerilme yığılma katsayıları hesaplanmıştır. Çözümde Sonlu Elemanlar Metodu kullanılmıştır. Sonlu elemanlar Metodunu paket programı olan SAP90 programı kullanılarak bilgisayarla gerilme değerleri hesaplanmıştır. SAP90 programı kullanılırken Q Edit kelime işlemcisinden civatalar tanımlanmış ve bu veriler SAP90 da kullanılmıştır. Üç değişik çaplı civata (M10, M12, M16) ile değişik radyüsler kullanılarak sonuçlar irdelenmiştir. Anahtar Kelimeler : Civata, Üç Boyutlu Gerilme Analizi, Sonlu Elemanlar Metodu STRESS ANALYSIS IN BOLTS WITH FINITE ELEMENT METHOD SUMMARY In this study three dimensional stress analysis has been made, tn the bolts subjected to the axial loads stresses have been investigated in the bolt heads and threads. These stresses are examined according to the radii that pass from uniform circular cross section area of the bolt to head area. In the solution, The Finite Element Method is used. Stress values are calculated with Computer which has software of Finite Element Method (SAP90). While SAP90 is used, bolts are descripted by Q Edit word processor and these data are used in SAP90. The results are discussed by using the bolts with three different diameters, (M10, M12, M16), were used, and their head radii. Key Words : Bolt, Three Dimnesional Stress Analysis, Finite Element Method 68

ÖZET BİLGİSAYAR YARDIMIYLA KULLANICI ETKİLEŞİMLİ STANDART CIVATA SEÇİMİ VE CİVATALI BA5LANTILARIN ANALİZİ YILMAZ, Levent Yüksek Lisans Tezi, Mak. Müh. Bölümü Tez Yöneticisi t Doç. Dr. R. Orhan Yıldırım Nisan 1990, 141 sayfa Bu çalışmada çeşitli yüklemeler altındaki bası civatalı bağlantıların bir IBM-XT uyumlu mikroilgisayar kullanarak standart civata, pul, somun seçimi ve analizleri yapılmıştır» Bu amaçla 6W-Basic programlama dilinde kullanıcı etkileşimli bir bilgisayar programı hazırlanmıştır. Başlıca vidalı bağlama elemanları olarak civatalar, somunsus vidalar, saplamalar ve diş tipi olarak dünyadaki yaygın kullanımı nedeniyle, `ISO-Metric` seçilmiştir. Programda çekme, kesme, ve bileşik yükleme altındaki contalı ve contasıs civatalı bağlantılar gözönüne alınmıştır. Eğilme gerilmelerinin etkisi bağlantının emniyet katsayısının artırılması ile karşılanmıştır. -v-Bağlantıdaki hem statik hem de dinamik ( sıfır ile maximum bir değer arasında tekrarlanan ) yükler gözönüne alınmıştır. Dinamik yük altındaki bağlantıların sonlu ve sonsuz ömür kıstaslarına göre tasarımı yapılabilmektedir. Civatalı bağlantıların sağlamlığı yükleme durumunda olduğu kadar ön sıkma durumunda da incel enmektedir. Seçim ve analizde civata güvenilir yükü, ilk sıkma yükü, en az sıkıştırma yükü, ve en çok civata yükü ana parametreler olarak gözönüne alınmıştır. Program iki amaçla kullanılabilmektedir. Birincisi, verilen yükleme ve geometrik kısıtlamalar gözönüne alınarak standart civata, pul ve somunun, sayı, tip ve boyutlarının civatalı bağlantı için belirlenmesidir, ikincisi ise, varolan bir bağlantının değişen girdilere göre analizini yapmaktır. Anahtar kelimeler bilgisayar yardımıyla standart civata seçimi, civata, ayrılabilir bağlantı, civatalı bağlantı Bilim Kodu : 625.02.07 -vı- ABSTRACT INTERACTIVE COMPUTER AIDED SELECTION OF STANDARD BOLTS AND ANALYSIS OF BOLTED JOINTS YILMAZ, Levent M.S. in Mechanical Engineering Supervisor s Assoc. Prof. Dr. R. Orhan YILDIRIM April 1990, 141 pages In this study, the selection of standard bolts, nuts, and washers and the analysis of certain bolted joints under various types of loading have been performed by using an IBM-XT compatable micro- computer. For this purpose, an interactive computer program has been prepared in GW-Basic language» Bolts, cap screws, and studs are selected as the basic types of screw fasteners, and ISO-Metric thread type is considered due to its world-wide use. In the program, metal to metal and gasketed types of bolted joints under pure tension, pure shear, and combined loading are considered. The effect of bending stresses is compensated by increasing the overall safety factor of the joint. -in-Both static and fatigue ( varying between zero and a maximum value ) loadings of joints are taken into, account. For the -fatigue loading, the joint can be designed -for in-finite li-fe or -finite life. The strength of the bolted joints is examined during loading as well as during tightening. Bolt proof load, initial tightening load, minimum clamping load, and maximum bolt load are considered to be the basic parameters in the selection of bolts and analysis of the joint. The program has two modes of operation. First one is the selection of number, size and type of standard bolts, nuts and washers for a bolted joint under consideration with given loading conditions and geometric limitations. The second one is to analyse an already existing joint for changing inputs. Key words t computer aided selection of standard bolts, bolt, detachable joint, bolted joint Science Code ! 625.02.07 -iv- 141