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Itoh, Yoshito, Yasuo Kitane, and Xiao Chen. "Evaluation of repair design on corrosion-damaged steel pipe piles using welded patch plates under compression." 土木学会, 2011. http://hdl.handle.net/2237/18848.
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Lewis, Bridget A. "Measurement of stress in weldments by magnetoacoustic emission." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360391.
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Nezo, Janos. "Virtual fabrication of full size welded steel plate girder specimens." Thesis, Heriot-Watt University, 2011. http://hdl.handle.net/10399/2433.
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The use of virtual experiments of welded steel plate girders are commonplace in modern structural research. One key factor in the success of using such numerical analysis is the availability and reliability of input data including imperfections such as initial deformations and residual stresses. In this research a methodology combining experimental and numerical work is developed in order to use virtually fabricated welded specimens, which include the imperfections as a result of the manufacturing process, in virtual experiments. A series of experiments are performed to calibrate and validate the numerical models. Temperature measurements are conducted in a steel structure factory during the welding of plate girders. The measurement methodology developed combines two types of measurements using an infrared thermometer without disturbing the fabrication process itself. The residual stresses are measured using a modified hole drilling method. Geometrical imperfection measurement results are also available from other related projects. For the numerical simulation of welding a mixed time integration scheme is proposed. For the modelling of the heat source of welding an “equivalent prismatic heat source model” is developed, which is very robust and allows for very simple calibration. Both thermal and thermal stress analyses of the welding process are performed including a large number of parametric studies. The residual stress measurements are also numerically investigated and calibration tables are developed to evaluate the measurements considering inaccuracies in their execution. The fabrication of full size plate girders is simulated. The calculated and measured web deformations are compared and reasonable agreement is found. Finally, to demonstrate and summarise the achievements of this research, a virtual specimen is used in a virtual experiment in which the ultimate behaviour of a plate girder is studied.
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Ifland, Chad. "TENSILE STRENGTH OF STEEL PLATES USING LONGITUDINAL WELDS." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/800.
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When a tension steel plate is welded to a gusset steel plate and a tension load is transmitted to the gusset plate by longitudinal welds along both edges at the end of the tension plate, the shear lag factor (U) is used to determine the design tensile strength for the plate. The shear lag factor is determined from the American Institute of Steel Construction (AISC) Manual. The shear lag factor is selected from the table based on the length of the weld and the width of the steel plate that is in tension. The thickness of the plates, boundary condition of the gusset plate, the size and strength of the weld is not taken into account when determining the shear lag factor. This study will investigate if these factors will affect the design tensile strength for a tension plate welded to a gusset plate by longitudinal welds. NISA, finite element analysis software, will be used to determine the ultimate load the tension plate can handle before it fractures. Then the results will be compared to the design strengths calculated by using the shear lag factors earlier stated.
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Meads, David. "P-DELTA EFFECTS ON STEEL MOMENT FRAMES WITH WELDED FLANGE PLATE CONNECTIONS." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/555.
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The P-Delta effect occurs when a frame or structure is laterally displaced by either seismic or wind loadings. As the structure is being displaced laterally, gravity begins to act on the members causing a secondary effect of the forces and moments which in turn cause additional displacement. The purpose of this study is to investigate the P-Delta effect on multi-story steel framed structures with welded flange plate connections. The traditional method regarding the calculation of the P-Delta effect assumes the lateral displacement of the steel columns is due to lateral deflection only and does not take joint rotation into account. In this study, a finite element analysis using computer models will be used to investigate the additional lateral displacement from the P-Delta effect due to the addition of joint rotation.
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Petersen, Troy A. "The displacement ductility of steel moment resisting frames using welded flange plate connections /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1136091371&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Blumenbaum, Stephen E. "Response of Cyclically Loaded Extended End-Plate Moment Connections When Used With Welded Built-Up Sections." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10060.
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An experimental investigation was conducted to study the behavior of extended end-plate moment connections subjected to cyclic loading. Eleven specimens were tested, representing typical connection configurations used in the metal building manufacturing industry. Four of the beams were shallow (30 in. or less), and seven were deep (60 in. or more). Two of the beams had compact webs, two had non-compact webs, and seven had slender webs. All specimens were designed according to the "thick plate" procedure contained in AISC Design Guide 16, Flush and Extended Multiple-Row Moment End-Plate Connections. A displacement-controlled history was used to load the specimens. Experimental maximum moments were compared to analytical predictions of beam and connection strength. Also, each moment versus rotation relationship was analyzed for compliance with the requirements of Ordinary, Intermediate, and Special Moment Frames, as defined by AISC in the Seismic Provisions for Structural Steel Buildings.
The experimental results demonstrated that the thick plate procedure in Design Guide 16 is an accurate model for predicting the strength of the connection elements, and the procedure is recommended for designing connections subject to cyclic (seismic) loads. The connection design moment should be based on the expected plastic strength of the beam, regardless of the equations governing nominal beam strength.Master of Science
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Boutzas, John-Alexander, and Dafina Zeka. "Patch loading resistance of welded I-beams : with respect to misaligned web stiffeners." Thesis, KTH, Stålbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199213.
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When a concentrated load is introduced perpendicular to the flanges of a steel beam, this condition is referred to as Patch loading (Gozzi, 2007). This occurrence is common in many steel structures, for example at supports or during launching of bridges. Because of the usual slenderness of I-beams and other plated structures, these are sometimes reinforced with stiffeners in order to avoid buckling. Modifications, such as adding stiffeners to a beam, are done to make greater plastic deformations possible before buckling can occur; thereby increasing the resistance against failure. Transverse stiffeners are added in areas where the beam is exposed to concentrated loads (Lagerqvist, 1994). The descriptions of calculating patch loading in the Eurocode are presented for cases of double stiffeners, with the load applied in between two stiffeners with same distance to each of them, or when there is one single stiffener that is acting in line with the load. In the Eurocode there are also descriptions on how to calculate on the resistance against patch loading when there are no stiffeners added. However, the Eurocode lacks descriptions for cases when the stiffeners are misaligned. The purpose of this paper is the evaluation of the impact from transverse stiffeners to the resistance of welded I-beams, when the stiffeners are misaligned and where the length of the beam varies. Because of the complexity of such of problems it is almost impossible to find theoretical solutions (Lagerqvist & Johansson, 1996). Therefore, in this study as well as in almost all studies that aim to predict the ultimate resistances of steel beams subjected to patch loading, the results are gained empirically. The tests herein were done by FE-modeling and the results from the physical experiments done in Lagerkvist’s doctoral thesis were used for validation of the model, as conducting experiments ourselves was not economically possible. 6 The study was made in two steps. In the first step FE-models were produced under the same circumstances as the results obtained by Lagerqvist (1994). Those analyses were not part of the aim of the study; the intention for making the initial analyses was to strengthen the reliability of the results. From there, the final analyses were made with the aim in investigating the influence of stiffeners on the resistance, when these are misaligned. In this step, observations were also made with regards to the impact of the bending moment of the beam on its resistance. The initial analyses, which were made for validation of the modeling, had a satisfying correspondence to the physical experiments; hence the final analyses are assumed valid of acceptance. From observations of the results in the final analyses it is noticed that adding stiffeners is a highly preferred way of increasing the resistance for slender beams. For full utilization it is however important to have the stiffeners optimally placed, because a small deviation from this position gives an unwanted decrease in resistance.
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Hosseinioun, M. M. "The influence of welding parameters and parent plate metallurgical characteristics on solidification of austenitic stainless steel weld metals." Thesis, Brunel University, 1988. http://bura.brunel.ac.uk/handle/2438/5394.
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The present work reports the effect of heat input, cooling rate, parent plate deformation and restraining conditions on the formation and morphology of delta ferrite in welds on AISI 318L and 321 steels. The experiments were carried out on commercially produced plates in the following conditions: (i) as received condition (ii) further deformed by cold rolling. (iii) further deformed by hot rolling. The effect of heat input and cooling rates were examined using bead-onplate Submerged Arc welds on the same parent plate material. The parent plate condition was assessed using bead-on-plate metal Inert Gas (MIG) and Subm rged Arc butt welds. The results suggest that 1. The weld metal solidification proceeds epitaxially from the existing unmelted base metal. The weld exhibited surface marking i.e. deformation bands or close packed plane, in the austenite matrix, but not passing through delta ferrite phase. 2. The solidification substructure, the ferrite content, and morphology are influenced by tile (i) thermal stress induced during welding, (ii) parent plate chemical composition, (iii) the parent plate microstructural and deformation characteristics i.e. strain energy. 3. Rapidly cooled welds have lower ferrite content than welds produced with slower cooling rates. The randomly distributed elongeed ferrite with some lath type ferrite morphology was predominantly attributed with the welds produced with high cooling rates. 4. The ferrite is the first solidified phase to form and austenite is formed from the liquid rather than by solid phase transformation of primary ferrite to austenite. 5. The ferrite formation is a diffusion controlled phase transformation, the degree of its dendrites development depends upon the welding parameters i.e. heat input, cooling rates. 8. Two types of ferrite morphology were observed: (a) elongated type dendrites identified as vermicular by previous investigators and (b) the cellular type morphology which has not been classified in previous investigations.
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Ferrari, Marcello. "Soldagem de chapas grossas em aço baixa liga temperado e revenido ASTM A514 com aço carbono ASTM A36 pelo processo arame tubular." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-31032017-141554/.
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Neste trabalho foram determinadas as condições para a soldagem de chapas grossas de aço carbono ASTM A36 com aço baixo-liga temperado e revenido ASTM A514 Grau Q empregando-se o processo arame tubular. Para tanto foram soldadas diversas peças de testes com o intuito de se avaliar as condições mais adequadas de preparação e soldagem de juntas dissimilares destes materiais. A preparação foi realizada por meio de corte térmico. A temperatura de preaquecimento foi determinada através de modelos matemáticos, pelas recomendações das normas AWS D1.1 e DIN EN 1011-2 sendo posteriormente avaliada por intermédio do teste de soldabilidade tipo CTS Controlled Thermal Severity. Os parâmetros de soldagem foram determinados a partir da qualificação de um procedimento de soldagem, conforme a norma AWS D1.1. Foram avaliadas as consequências do emprego do tratamento térmico de alívio de tensões após soldagem (TTAT), pelos testes de dureza Vickers e impacto Charpy. A caracterização microestrutural foi realizada por meio de microscopia óptica e microscopia eletrônica de varredura. A caracterização das superfícies oxicortadas evidenciou os efeitos da descarbonetação e também da carbonetação. A temperatura de pré-aquecimento de 160°C determinada por meio da metodologia recomendada pelas normas AWS D1.1 e DIN EN 1011-2 mostrou-se satisfatória nos testes de soldabilidade. Foi possível a qualificação do procedimento de soldagem (EPS) com requisitos de impacto na condição \"como soldado\", porém na condição \"após TTAT\", os baixos valores de tenacidade obtidos no metal de solda, inferiores a 27J, não permitiram a qualificação de uma EPS com requisitos de impacto. Foi observada a ausência de trincas intergranulares tanto na zona afetada pelo calor quanto no metal de base ASTM A514, porém foi revelada a presença de microfases frágeis no metal de solda na condição \"como soldado\", especificamente na região da raiz, intensificadas pelo efeito da diluição. O aumento do teor de carbono na raiz, a presença de microfases frágeis, a grande fração de grãos colunares e de ferrita proeutetóide combinados com a baixa fração de ferrita acicular no metal de solda contribuíram para os baixos valores de tenacidade encontrados na condição \"como soldado\". Após o TTAT observou-se uma queda acentuada da tenacidade, inferior a 27J, do metal de solda devido à fragilização provocada pela precipitação e coalescimento de carbonetos de ferro.In this work it was determined the conditions for welding thick plate of ASTM A36 carbon steel with quenched and tempered low-alloy steel ASTM A514 Grade Q employing the Flux Cored Arc Welding (FCAW) process. For that several coupons of tests were welded in order to evaluate the most appropriate conditions for preparation and welding of these dissimilar materials. The preparation was carried out by means of thermal cutting. The preheat temperature was determined by mathematical models, the recommendations of standards AWS D1.1 and DIN EN 1011-2 being further evaluated using the CTS type weldability test - Controlled Thermal Severity. The welding parameters were determined by qualifying a welding procedure (WPS), according to AWS D1.1. The effects of post weld heat treatment (PWHT) were evaluated by Vickers hardness tests and Charpy. Microstructural characterization was performed by optical microscopy and scanning electron microscopy. The characterization of oxi-fuel cut surfaces showed the effects of decarburization and also carburization. The preheating temperature of 160 °C determined by calculation and the methodology recommended by the standards was satisfactory in weldability tests. It was possible qualification of welding procedure (WPS) with impact requirements in the condition \"as welded\" but the condition \"after PWHT\" low toughness values obtained in the weld metal, less than 27J, did not allow to qualify a WPS with toughness requirements. The absence of intergranular cracking was observed in both the heat affected zone as the base metal ASTM A514, but the presence of fragile microphase in the weld metal was revealed in the weld metal in the condition \"as welded\" specifically in the root region, intensified by the effect of dilution. The carbon increase at root, the presence of fragile microphase, the large fraction of columnar grains and proeutectoid ferrite combined with the low fraction of acicular ferrite in the weld metal contributed to the low toughness values found in the condition \"as welded \". After PWHT there was a sharp drop in toughness, less than 27J, in the weld metal due to embrittlement caused by precipitation and coarsening of iron carbides.
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Walimbe, Anmol. "Investigation of Shear Lag and Eccentric Weld Demands on Top Chord Knife Connections in Open Web Steel Joist Girders." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623165008367418.
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Cikánek, Ondřej. "Studie styčníků rámových ocelových konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265499.
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Master's thesis „Study of joints of frame steel structures“ examine certain analysis types of frame steal joints, which are analysed both by component method and by specialized software IDEA RS. Obtained results are compared by both methods, in terms of load-bearing capacity and in terms of stiffness. Theoretical joints stiffness calculation according to standard ČSN EN 1993-1-8 is included in the introductory part of the thesis. In the second part, joints are designed to bear inner forces and moments, which were created by load combination effects and then analysed.
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Družbík, Jiří. "Sportovní hala v Písku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225533.
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The theme of the master’s thesis is to design steel structures sports hall. The proposal is developed in three variants according to ČSN EN. The work addresses the static effect of the steel structure and design of parts and materials design. Plan dimensions are 60x38m, max. internal height is 9,3m. The structure is designed for ultimate limit states and serviceability. The supporting structure is designed as roof arches surround an elliptical girder. In both gable walls are designed steel columns. The work also details and solution design. Sports hall was solved in Scia Engineer 2011 and includes a drawing documentation.
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Thomanková, Lucie. "Nosná ocelová konstrukce prodejny a opravny automobilů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225691.
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Diploma thesis includes design and examination of steel load-carrying structure. Construction includes car deal warehouse and car repair shop with extension for car varnishing. Car deal warehouse has ground dimensions 22 x 30 m and total high 10 m. Main frame is composed of Vierendeel trusses with arc shape. Car repair shop has ground dimensions 20 x 30 m and total high 10 m. Main frame is composed of truss girders and web-plate columns. Frame extension has ground dimension 20 x 10 m and total high 6,4 m. Cladding is composed of sandwich panels. Store´s gable wall and a part of the roof are glass. Climatic load is intended for locality Ostrava.
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Mannem, Rajaprakash. "Shear lag effects on welded steel angles and plates /." 2002.
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Wei, Ber-Lin. "The static in-plane strength of welded steel plate I-girders under bending /." Diss., 1998. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9914252.
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Chen, Yu, and 陳佑. "An Investigation on Microstructure of High Heat Input Welded Steel Plates with Ti、B、Nb." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/51705115553236427538.
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碩士國立臺灣大學
材料科學與工程學研究所
97
To support the recent construction and transportation industries, a high strength steel plate associated with the high heat input welding technique has been developed. By alloy design, controlling austenite grain size and desired microstructure, the toughness in heat affected zone has been largely improved. The high heat input welded steel plate is produced by China Steel Corporation.In one aspect, the purpose of this study is to understand the relationship among microstructure of welded zone, microstructure of heat affected zone and the excellent mechanical properties after welding. In the other aspect, this study aims to elucidate the transformation mechanism of intragranular ferrite(IGF) in the heat affected zone. The microstructure of welded and heat affected zone have been investigated by optical microscope and transmission electron microscope. The acicular ferrite in welded zone and intragranular ferrite in heat affected zone both have high dislocation density. By addition of Ti, Nb, B, the prior austenite grain size can be refined to 500μm. Besides, the amount of widmenstatten ferrite can be reduced and further increase the amount of Intragranular ferrite by the present alloy design. Such a fine microstructure in the heated affected zone achieves excellent toughness superior to the toughness in welded zone. In order to study the transformation mechanism of intragranular ferrite, Gleeble machine was used to simulate the practical welding condition and the microstructure was studied by step quenching method using OM and TEM. During the cooling process, the complex carbonitrides (Ti,Nb)(C,N) precipitated from austenite grain with the cube-to-cube orientation relationship. These carbonitrides act as the nucleation sites for intragranular ferrite. The intragranular ferrite precipitating on the carbonitrides with the Baker-Nutting orientation relationship is called primary IGF. The following Intragranular ferrite called secondary IGF can transform by sympathetic nucleation and adopt K-S orientation relationship with the prior austenite grain.
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Ngoc, Minh Tran, and 陳玉明. "Behavior of High Performance Steel with Thick Plate Welded by High Heat Input." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/a2bknz.
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碩士國立臺灣科技大學
營建工程系
100
High performance steel (HPS) are steel which exhibit improved strength, weld ability, ductility and energy absorption. These enhanced properties compared to conventional steel may give HPS protective properties against extreme loads that may occur in earthquakes. For high-rise building in Taiwan, HPS has many further practical applications. However, the cause of brittle failure in box columns-beams welded joints still exits such as fracture at column and diaphragm electro gas welding (EGW) cause of the effect of high heat input welding and welding defects. Furthermore, the impact of this effectiveness in the intersection area will be more serious under seismic loading because the swing of beam establishes the forces which directly go through column beam joint welded. In order to ensure the structural stability and ductility requirement, the damage should not occur at the junction and make beam getting to plastic period. In this study, the structural characteristics of welded joint area were investigated through experimental and analytical procedures, including (a) behavior of jumbo specimen under series of loading test, (c) analytical model studying stress intensity factor of welding joint.
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Marquez, Alberto C. "Finite element analysis of welds attaching short doubler plates in steel moment resisting frames." Thesis, 2014. http://hdl.handle.net/2152/28259.
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A number of recent research studies have investigated the performance of panel zones in seismic-resistant steel Special Moment Resisting Frames (SMF). These recent studies investigated various options for attaching doubler plates to the column at beam-column joints in SMF for purpose of increasing the shear strength of the panel zone. This previous work was primarily focused on doubler plates that extend beyond the top and bottom of the attached beams, and considered cases both with and without continuity plates. As an extension to this previous research, this thesis explores the situation when a doubler plate is fitted between the continuity plates. The objective of this research was to evaluate various options for welding fitted doubler plates to the column and continuity plates through the use of finite element analysis, and to provide recommendations for design. The development and validation of the finite element model are described, along with the results of an extensive series of parametric studies on various panel zone configurations and attachment details for fitted doubler plates. Based on the results of these analyses, recommendations are provided for design of welds used for attaching fitted doubler plates in the panel zone of SMF systems.text
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Chou, Wei-Chuan, and 周煒筌. "Residual stress of low-carbon steel pipe/plate welded after the vibratory stress relief treatment." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/56912311134334585148.
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碩士國立中興大學
材料科學與工程學系所
104
This study investigates ASTM A285 Gr.C low-carbon steel by Shielded Metal Arc Welding (SMAW) to simulate the real state heat exchanging pipes in nuclear power plant. It carries out vibratory stress relief (VSR) after welding and further use X-ray of the Cr target-cosα law to measure residual stress and metal magnetic memory (MMM) of the stress concentration zone (SCZ) non-destructive testing (NDT), which compares the relationship between residual stress, mean-full width at half maximum (FWHM) and magnetic intensity of MMM. According to the results that SCZ of weld piece can be learned by MMM and find the SCZ of magnetic intensity of weld fusion zone(WFZ)(width:12mm) of pipe weld piece is wider with residual stress distribution. However, the SCZ of magnetic intensity of WFZ (width:10mm) of pipe/plate weld piece is more narrow. It is possible to have a qualitative relationship between the magnetic intensity and residual stress. In residual stress of pipe-pipe welding analysis that rare compressive stress occurs and the maximum compressive stress in the center-WFZ occurs as well between -200MPa and -279MPa；After handling by VSR , the maximum stress can be relaxed up to 40% due to the largest initial residual stress. From the residual stress of pipe/plate welding analysis, it is theoretical tensile stress. The maximum tensile stress is at the upper-WFZ when between 211MPa and 254MPa. The heat-affected zone (HAZ) has the best stress relaxation rate with more than 45% after VSR. Through the analysis as aforementioned, the study found that it is not appropriate to use relaxation rate to represent the effect of relaxation, the amount of relaxation should be the one to be represented. The higher the initial residual stress is, the greater the amount of relaxation being measured. From the mean-FWHM analysis of pipe weldments, HAZ has a larger amount of change in the mean-FWHM(0.05 degrees to 0.25 degrees). When the changing amount of mean-FWHM of WFZ is less than 0.05 degree, which means the effect of thermal cycling in HAZ leading to non-uniform grain size inside, and resulted to be divided into the grain growth zone, recrystallization zone and recovery zone. Additionally, keeping away from heat received by the heat is different that the lattice strain state is more complex in the HAZ. Consequently, defects will also affect the state of mean-FWHM. The numbers of defects in WFZ are less than HAZ and the main dislocations are decomposed into partial dislocations that reduce strain energy and strain degree during VSR process in HAZ. Therefore, the experiment confirms that it can improve the non-uniform state of strain of HAZ after VSR process. Hence, the HAZ have a large amount of changes in the mean-FWHM.
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Chiou, Rong-Chieh, and 邱榮杰. "Performance Assessment of Steel Coupler and Investigation of the Strength of Welds Used to Connect Coupler and Steel Plate." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/92892738859988497708.
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碩士國立台灣工業技術學院
營建工程技術研究所
85
In this study, the strength of welds connecting steel plate and steelcoupler is investigated. A total of 88 specimens, including partial penetration groove welds with single-J bevel and fillet welds, using #10 steel coupler are tested. Test results show that：(1) AWS prequalified partial penetration groove welds with single-J bevel is suitable for assemblage of couplers and steel. (2) The formula suggested in chapter 4 gives a good estimation of the weld strength of partial penetration groove welds with single-J bevel couplers, (3) In the practical range, the thickness combination of box column plate and diaphragm does not influence the strength of welds. (4) Eccentricity, between coupler and diaphragm, smaller than 7 mm, does not decrease the strength of welds.
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Kleineck, James Robert. "Galvanizing crack formation at base plate to shaft welds of high mast illumination poles." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-3966.
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High mast illumination poles (HMIPs) are tall cantilevered structures used to efficiently illuminate large portions of highways and interchanges. Great interest in the performance of HMIPS has arisen from the discovery of extensive premature cracking at the toes of base plate to pole shaft welds of poles currently in service. These cracks, in some cases, have become so severe that HMIPs have actually collapsed, and therefore present a great threat to public safety.
Previous research at the University of Texas at Austin sought to solve the design problems posed by these pole failures by conducting both full-scale and analytical tests on optimized designs of HMIPs for fatigue loads. These studies indicated that using full penetration welds to connect 3" thick base plates to relatively thin shaft walls minimized warping of the base plate during fatigue loading, and maximized fatigue performance.
Toward the end of these studies when researchers sought to test an uncoated optimized HMIP back-to-back against a galvanized HMIP of the same design and material, researchers discovered the galvanized specimen had cracked during the galvanizing
process. This finding prompted an in-depth study to determine the cause of these cracks, and to determine if practices could be implemented to prevent crack formation.
Initially, bend radius, chemistry, and shaft to base plate thickness studies were conducted to find how these parameters affect HMIPs during galvanizing. These parameters were found to play a minor role in the cracking of HMIPs relative to the thermal effects induced during the galvanizing process. Full-scale and analytical tests verified the impact of thermal straining within HMIPs during galvanizing. Instrumenting HMIPs and smaller HMIP stub sections with thermocouples and strain gages provided temperature and initial strain gradients resulting from exposure to the molten zinc bath. This data, as well as observations of cracks in the tested HMIP sections, aided the development of a finite element parametric study comparing HMIPs of the same 150' length and 80 mph design but varying shaft thicknesses. This research concludes that reducing the pole shaft diameter to thickness ratio reduces the likelihood of galvanizing crack formation.text
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Neilson, David Andrew Hunter. "Welding of light gauge infill panels for steel plate shear walls." Master's thesis, 2010. http://hdl.handle.net/10048/1436.
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Ductile steel plate shear walls are an established lateral load resisting system. Past research indicates that cold-rolled infill panels less than 1 mm in thickness present one solution to an overstrength problem arising from selecting an infill panel thickness based on ease of welding and handling. This research program examines several possible welding procedures and joint geometry to connect the thin infill panel to the thick boundary elements.
Primary welding parameters include short-circuiting gas metal arc welding process, electrode and shielding gas selection, heat input, and use of a chill strip. Four configurations of the infill panel-to-boundary element joint and two configurations of a lap splice joint between two sheets of thin steel in the infill panel were tested in monotonic tension and cyclic tension-compression. A quasi-static cyclic test of a single-storey moment resisting frame steel plate shear wall validated the use of one welding procedure and joint geometry.Structural Engineering
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Huang, Chun-Chieh, and 黃軍傑. "The Stress and Strain Analysis of SUS304 Steel Plate With T-joint Fillet Weld." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/t3v6k6.
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碩士國立高雄應用科技大學
機械工程系
105
In this paper, we study the residual stress and deformation of welding of SUS304 steel plate by using MSC.MARC finite element software and SE-FIT surface fluid simulation software. In this paper, by using Surface SE-FIT to establish a more accurate bead shape, and then use the common file IGES to import MSC.MARC finite element software analysis welding simulation, to explore the different weld bead shape, different absorption power, warm up ... and so on. The results show the following points, First , by the SE-FIT simulation bead and the post-test specimen is basically the same shape of the weld bead. Second, the fixed welding speed, the welding absorption rate of each rise of 0.1 its peak temperature will rise about 200 ℃ or so. Third, the welding preheating temperature of 200 degrees C, the residual stress after welding the most obvious decline.
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Voth, Andrew Peter. "Branch Plate-to-circular Hollow Structural Section Connections." Thesis, 2010. http://hdl.handle.net/1807/26253.
Full textAbstract:
Although branch plate connections with circular hollow section (CHS) members are simple to fabricate and cost-effective, they are generally very flexible under low load application resulting in the limit states design resistance being governed by an imposed deformation limit. Restricting the ultimate capacity of a branch plate connection by a deformation limit results in the inherent strength of the CHS member being
under-utilized, highlighting the need to develop connection stiffening methods. Two methods to stiffen branch plate-to-CHS connections are examined: a through plate connection and a grout-filled CHS branch
plate connection. Further, the current design guidelines of various plate-to-CHS connection types are reexamined including the effect of chord axial stress and chord length on connection behaviour. Finally, the
behaviour of connections with non-orthogonal or skew plate orientation, which has not previously been examined, was studied in depth.The behaviour of these uniplanar connection types under quasi-static axial loading was studied through 16 large-scale laboratory experiments and 682 numerical finite element analyses, as well as an extensive review of all previous international experimental and numerical findings. The extensive study formed the
basis for a complete set of proposed design guidelines and provided insight into plate-to-CHS connection behaviour. For all plate-to-CHS connection types, the plate thickness is shown to effect connection capacity, though previously this was thought not to have significant impact on connection behaviour. The existing ideology of using the same design recommendations for tension- and compression-loaded connections, which was developed from compression results, under-utilizes an inherent increase in capacity provided by a connection primarily loaded in tension. As such, the recommended design guidelines split the two load senses into separate expressions that reflect the difference in behaviour. Stiffened through plate connection behaviour was determined to be the summation of branch plate behaviour in compression and tension, leading to a significant increase in capacity and identical behaviour regardless of branch load sense. The skewed branch plate connection behaviour was found to relate directly to the established behaviour of longitudinal and transverse plate connections. A design function was developed that interpolates the capacities of intermediate angles by using the proposed design recommendations of the two extreme connection types. Finally, the examination of chord axial stress and chord length for plate-to-CHS connections yielded results similar to previous international studies on CHS-to-CHS connections. The effect of chord length, however, has wide-reaching implications as to how experimental and numerical FE research programs are developed.
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Pepin, Joel. "Effects of Submerged Arc Weld (SAW) Parameters on Bead Geometry and Notch-Toughness for X70 and X80 Linepipe Steels." Master's thesis, 2009. http://hdl.handle.net/10048/665.
Full textAbstract:
For the manufacture of higher strength pipelines to be feasible, a better understanding of the effects of welding on toughness is necessary. Bevel submerged arc welds were performed on X80 grade steel. The subsequent Charpy V-notch (CVN) test results indicated that the notch placement in the various heat affected zone regions, and hence the bead geometry, affected the test results. A series of bead-on-plate (BOP) submerged arc welds then were performed on X70 grade steel plate to determine the effects of current, voltage, heat input, polarity, and waveform manipulation (i.e., balance, offset, and frequency) on both single and tandem weld bead geometry. A new bead profile characteristic, the SP ratio, is proposed to describe weld bead geometry, and its relationship with welding parameters is discussed. Sub-size CVN specimens, pulled from many of the BOP weld coupons, were then tested. The greatest subsize CVN fracture energies were achieved when the bead was produced using lower heat input, and when the bead profile possessed a greater SP ratio.Materials Engineering
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Ling, Kuo-Hsia, and 凌國夏. "Groove Configurations and multi-pass Temper Bead in Flux Cored Arc Welding Process Used in Thick Steel Plate Welds of Large Structures: Mechanical properties and Metallurgical Studies." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/97kur4.
Full textAbstract:
博士國立中央大學
機械工程學系
104
Ships, bridges, pressure vessels, industrial machinery, automobile, rolling stock and many other fields are all produced by welding technology. The common problem in these fields is associated with welding process. The maximum hardness of the heat affected zone (HAZ) and the cold cracking susceptibility of welds are results in Weldability of steel. This paper utilized a flux-cored arc welding (FCAW) technique and investigated various groove configurations as well as multi-pass welding sequences to create welding specifications in the mechanical press industry. Experimental investigations were conducted to examine the influence of three different groove configurations of JIS SS400 structural steel welded joints on mechanical and metallurgical properties. Mechanical properties of the welded joints were evaluated by uniaxial tensile testing and Charpy V-notch (CVN) impact testing at room temperature. Simultaneously after a multi-pass welding sequence, various degrees of thermal treatments such as tempering or normalization inevitably occur in the heat affected zone (HAZ). The unfavorable microstructures in the HAZ and reheated zones can be intentionally modified via the above procedure such that the toughness and microhardness of the HAZ improves. The experimental results revealed that of the three types of groove configurations (C1, C and F), groove type C1 possessed the maximum yield strength (YS) and ultimate tensile strength (UTS) while groove type F possessed the highest CVN values tested at room temperature. The fundamental reason may be attributed to heat dissipation characteristics of each groove configuration and associated exertion of the multi-pass welding sequence. Microstructural and morphological features as revealed through an optical microscope also indicate a significant influential factor of these joints among the different groove configurations. Therefore, grain refinement of varying degrees can be obtained due to the variation of thermal characteristics of heat input/dissipation and thus, various mechanical and CVN impact properties can be obtained. It further examined the effects of temper bead welding (TBW) made with two different welding processes, namely with 4 Layers 4 Passes (4L4P) and 4 Layers 10 Passes (4L10P). Thermocouples were fixed to measure the thermal cycles, and the temperature distribution curves along the weld seams were measured by Infrared Radiation (IR) images. All welded samples were checked using nondestructive Phased Array Ultrasonic Testing (PAUT) to ensure defect-free samples before the experiments commenced. The Charpy impact tests were finished in 20 and -20°C respectively. Vickers microhardness measurement was carried out at room temperature. The 4L4P welding process was found to improve the impact toughness of the welding joints. In addition, it was found that the 4L4P welding process produced an overall lower hardness than the 4L10P welding process.