Aviation is known to have some of the most stringent structural health monitoring standards in the world. An example of this would be the fact that certain bolts in the aircraft assembly must be periodically removed and inspected for fatigue damage. This can be a very costly endeavour: a case in point being the Hercules C130 aircraft, which requires approximately 200 man hours of down-time for the inspection of the bolts that attach the wings to the fuselage. The substitution of TRIP (Transformation Induced Plasticity) steel bolts for the current HSLA steel (AISI 4340) from which the bolts are manufactured, allows the bolt to act in the capacity of load bearing member as well as damage detector. This unique feature is a consequence of the transformation characteristic exhibited by TRIP steels when they are strained: an irreversible change within their microstructure from paramagnetic austenite parent phase to permanent ferromagnetic state occurs in direct proportion to the peak strain. This property allows us to establish a relationship from which the service life of the component can be determined. A prototype of a smart aircraft bolt and washer system has been developed, where the bolt acts as damage detector and the washer effectively examines the health of the bolt by reading the changing magnetic susceptibility of the bolt. This study presents both material development and product development phases of the Smart Aircraft Bolt prototype. A prediction of transformation characteristic due to deformation is carried out using finite element analysis (mechanical model) and a constitutive model (strain induced martensitic transformation kinetics) to predict the best situation for the smart washer. In addition, experimental work is performed in the form of cyclic temperature testing (with and without external loading) and tension-tension fatigue testing. For both sets of experimental testing, two positions of washer placement are tested. A correlation between volume fraction of martensite present and remaining life, is therefore possible. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 24, 2007) Includes bibliographical references.

Na maioria das construções utilizam-se estruturas de madeira para coberturas e muitas são executadas no sistema convencional, empregando treliças. Com o avanço da arquitetura, no que diz respeito a empregabilidade da madeira, outras formas vêm sendo utilizadas, tornando o ambiente mais livre e harmônico, e para isso, a necessidade de vigas maiores, para vencer maiores vãos. Desta forma, os materiais dos elementos estruturais têm importante papel, a fim de demandar continuidade das peças, dentro dos padrões de segurança. As Normas Brasileiras apresentam formas de ligações onde, o emprego da madeira e o aço, garantem a estabilidade para ambos os materiais, visto a utilização de parafusos e pinos como elemento de ligação, empregados nas construções. Neste trabalho, a proposta é avaliar os conjuntos dos materiais de ligações aparafusadas entre madeira/madeira e compará-la com a ligações madeira/chapa de aço/madeira; a chapa dobrada a frio e prensada entre as peças não está aparente. Portanto, a ligação ficará a cargo dos parafusos, mas, com a chapa a resistência será maior suportando aos esforços cortantes causados pela flexão dos parafusos e inserida diretamente na madeira, que tem grande importância quanto à direção das fibras e do esforço aplicado. / In most constructions are used wooden structures for roofs and many are executed in the conventional system using trusses. With the advancement of architecture, with regard the employability of timber, other ways have been used making the free and harmonious environment, and for this, the need for larger beams, to win larger spans. Therefore, the materials of the structural elements have an important role in order to demand continuity of parts with in the safety standards. Brazilian Standards of forms of links where the use of timber and steel, ensure stability for both materials, as the use of bolts and pins as liaison, used in buildings. In this paper, the proposal is to assess the joint of bolted connections materials between timber / timber and compare it with the connections timber / steel plate / timber; the folded plate and cold pressed between the parts is not apparent. Therefore, the connection will fall on the bolts, but with the plate resistance will be higher by supporting the shearing caused by the bending of the bolts and inserted directly on timber, which is very important as to the direction of the fibers and of the applied load.

The search for new and additional sources of energy -- from sun, wind, waves, and ocean currents -- is necessitating the development of structures in the open environment of the oceans as well as on land. The advantages of round or tubular members for use in such structures are shown; and to avoid the uncertainties of welded joints, two bolted connections are proposed and their feasibility explored.

ABSTRACT The task was to design and assess the supporting structure of the lookout tower. Material steel and wood. The lookout tower is 27.22 m high and decreases in height from the base of the srka. Construction system with continuous columns and horizontal reinforcement.

At the calculations group in Sigma Industry East North, the traditional method for evaluating fasteners has been by use of the VDI2230 manual. As the complexity of a model increases the evaluation also becomes harder. The goal of this thesis is to set a robust evaluation method by combining the VDI2230 with the Finite Element (FE) method. Varied topics such as fastener and plate compliance, embedding effect, forces through the fastener and plate, minimum thread engagement length, service loads and the fatigue effect in fasteners is discussed. The flowchart discusses the process flow, as in, where to use the VDI2230 and where the FE method comes into use. The thesis also helps to understand designing of bolts like selection of the bolt diameter of varied applications and is user friendly to handle. The focus is also on reducing the time taken for fastener evaluation and setting up of an in-house technique for the evaluation. The evaluation method is verified using a test case. / På beräkningsgruppen på Sigma Industry East North har den traditionella metoden för utvärdering av fästelement varit att använda sig av manualen VDI 2230. Ökad komplexitet gör utvärderingen svårare att genomföra. Målet med detta examensarbete är att föreslå en robust utvärderingsmetod som kombinerar VDI 2230 med Finita Element-Analys (FEA). Olika ämnen såsom vekhet för fästelement och plåtar, sättningar, kraftvägar genom fästelement eller plåtar, minsta ingreppslängd, laster och utmattningseffekter diskuteras. Flödesdiagrammet avhandlar processflödet, det vill säga var man ska använda VDI2230 och när FE-metoden bör användas. Examensarbetet är också till för att skapa förståelse för hur man konstruerar skruvar, såsom val av skruvdiameter vid olika tillämpningar. Fokus har också varit att minska tidsåtgången för utvärdering av fästelement och att sätta upp tekniker för utvärdering att användas i den dagliga verksamheten. Utvärderingsmetoden verifieras med hjälp av ett provfall.

An analytical and experimental investigation was conducted to study the six bolt flush moment end-plate connection configuration which is used in steel frame construction. The limit states of plate yielding and bolt fracture were analyzed using yield-line theory to predict endplate thicknesses and a split-tee analogy to develop a method to predict bolt forces. Five experimental tests were conducted on four configurations within a matrix of geometric parameters. The predicted ultimate moment showed good . correlation to the yield moment obtained from the experimental deflection plots. The experimental bolt forces correlated well with the predicted bolt forces when plotted versus the applied moment. Additionally, an equation to model the moment-rotation relationship was developed from a regression analysis to determine the construction type suitable for a given connection configuration. Finally, a method of designing the six-bolt flush end-plate configuration is presented and an example given. / Master of Science

Elektrische Verbindungen in der Elektroenergietechnik sind aus technologischen und konstruktiven Gründen beim Zusammenschalten von Betriebsmitteln in Schaltanlagen und auf den Übertragungswegen bei Kabeln und Freileitungen notwendig. Als elektrischer Kontakt wird die Berührung zweier stromführender Leiter verstanden. Eine Verbindungsart, die häufig bei Stromschienen eingesetzt wird, ist die Schraubenverbindung. Um eine Lebensdauer dieser Verbindung von üblicherweise 50 Jahren und mehr zu gewährleisten, ist es notwendig, die Alterung abhängig von der Zeit und der Temperatur zu kennen. Neben dem Kraftabbau und den chemischen Reaktionen / Fremdschichtbildung bei Verbindungen mit Kupfer- oder Aluminiumleitern ist die Interdiffusion bei Bimetallverbindungen und bei Verbindungen mit beschichteten Kontaktpartnern von Bedeutung. In dieser Arbeit wurde der Kraftabbau bei Schraubenverbindungen mit Stromschienen aus Cu-ETP (Werkstoff-Nr. CW004A) und CuAg0,1P (Werkstoff-Nr. CW016A) im Temperaturbereich zwischen 105 °C und 160 °C untersucht. Es wurde die Kraft und der Widerstand an stromdurchflossenen Verbindungen abhängig von der Zeit bis zu 2,4 Jahren gemessen. Des Weiteren wurde der Einfluss von verschiedenen federnden und nicht federnden Elementen im Verbindungssystem auf den Kraftabbau untersucht. Es wurde eine statische Mindestverbindungskraft bestimmt, der Kraftabbau bis zu einer Lebensdauer von 50 Jahren berechnet und daraus eine Grenztemperatur für diese Verbindungsart bestimmt. Neben dem Kraftabbau wurde die Alterung durch Interdiffusion an Schraubenverbindungen mit verzinnten und versilberten Cu-ETP Stromschienen im Temperaturbereich zwischen 115 °C und 140 °C untersucht. Es wurde an stromdurchflossenen und im Wärmeschrank gelagerten Verbindungen der Verbindungswiderstand abhängig von der Zeit bis zu 2 Jahren gemessen. Die Langzeitversuche wurden durch mikroskopische Untersuchungen ergänzt, in denen die Dicke der sich gebildeten intermetallischen Phasen gemessen und bewertet wurde. Ergänzend zu den Langzeituntersuchungen wurden aktuelle Erkenntnisse zu den chemischen Reaktionen / Fremdschichtbildung auf Kupfer-, Silber- und Zinnoberflächen zusammengestellt und bewertet. / Electrical joints are necessary for technological and design reasons to connect electric equipment and to realize the transmission of electrical energy by cables and overhead lines. The contact between two current-flown electrical conductors is called electrical joint. One joint type often used is the bolted joint. To allow a lifetime of this joint of 50 years and longer it is necessary to know the ageing depend on time and temperature. In addition to ageing by force reduction and the chemical reactions / impurity layers at joints with copper und aluminium conductors, the interdiffusion has a great influence at bi-metal joints and joints with plated conductors. In this work the force reduction was analysed at bolted joints with bus bars made of Cu-ETP (material number CW004A) and CuAg0.1P (material number CW016A) in a temperature range between 105 °C and 160 °C. The joint force and the joint resistance were measured time-depended at current-flown joints up to 2.4 years. Furthermore the influence on the force reduction by different resilient und non-resilient elements in the joint system was tested. There was a minimum static joint force appointed and the force reduction calculated to a lifetime of 50 years. Out of these results a category temperature for these joints was defined. Additionally the ageing due to interdiffusion at bolted joints with tin and silver plated Cu-ETP bus bars was analysed at the temperatures 115 °C and 140 °C. At joints aged by current-flown and in the heating cabinet the joint resistance was measured time-dependent up to 2 years. These long-term tests were supplemented by microscopic examinations. The thickness of the grown intermetallic compounds was measured and stated. Additional to the long-term tests the topical knowledge to chemical reactions / impurity layers at copper, silver and tin surfaces was composed and stated.

The use of the cold-formed steel sheet bolted connections without washers is so significant; however, the North American Specifications for the Design of Cold Formed Steel Structural Members, NASPEC, doesn't provide provisions for such connections. The bearing failure of sheet and the shear failure of sheet were considered in this study. For the sheet shear strength, it was found that the NASPEC (2007) design provisions can be used for oversized holes in both single and double shear configurations and for the double shear connections on short slotted holes. For the sheet bearing strength, a new design method was proposed to be used for low and high ductile steel sheets. The method was compared with the NASPEC and the University of Waterloo approach. Washers were still required for single shear connections on short slotted holes. Besides, connections using ASTM A325 bolts yielded higher bearing strength than connections using ASTM A307 bolts.

In cold-formed steel (CFS) construction, bolted connections without washers for either oversized or slotted holes may significantly expedite the installation process and lower the cost. However, the North American Specification (AISI S100, 2007) for the Design of Cold-Formed Steel Structural Members requires washers to be installed in bolted connections with oversized or slotted holes. A research project (Phase 1) sponsored by American Iron and Steel Institute (AISI) was recently completed at the University of North Texas (UNT) that investigated the performance and strength of bolted CFS connections with oversized and slotted holes without using washers. The research presented in this thesis is the Phase 2 project in which the bolted CFS connections were studied in a broader respect in terms of the failure mechanism, the material thickness, and the hole configurations. Single shear and double shear connections without washers using oversized holes, oversized combined with standard or slotted holes were experimentally examined. Combined with Phase 1 results, the Phase 2 gives a comprehensive evaluation of the behavior and strength of bolted CFS connections with oversized and slotted holes without using washers. Revisions to the existing AISI North American Specification requirements for bolted connections are proposed to account for the reduction in the connection strength caused by the oversized and slotted hole configurations without washers. Specific LRFD and LSD resistance factors and ASD safety factors for different hole configurations in terms of the new proposed methods were presented.