In current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This often results in oversized link elements, which leads to over-designed structures and foundations. In addition, the beams are expected to sustain significant damage through repeated inelastic deformations under design level earthquakes, and thus the structure may require extensive repair or need to be replaced. These drawbacks can be mitigated by designing EBFs with replaceable shear links. Two different replaceable link types with alternate section profiles, connection configurations, welding details and intermediate stiffener spacing were tested. A total of 13 cyclic quasi-static full-scale cyclic tests were performed, which included tests on eccentrically braced frames with the replaceable shear links, to study their inelastic seismic performance. The links exhibited a very good ductile behaviour, developing stable and repeatable yielding. Additional inelastic rotation capacity can be achieved with bolted replaceable links when allowing bolt bearing deformations to occur. The on-site replaceability of the link sections is confirmed even in the presence of residual deformations of 0.5% drift.

In current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This often results in oversized link elements, which leads to over-designed structures and foundations. In addition, the beams are expected to sustain significant damage through repeated inelastic deformations under design level earthquakes, and thus the structure may require extensive repair or need to be replaced. These drawbacks can be mitigated by designing EBFs with replaceable shear links. Two different replaceable link types with alternate section profiles, connection configurations, welding details and intermediate stiffener spacing were tested. A total of 13 cyclic quasi-static full-scale cyclic tests were performed, which included tests on eccentrically braced frames with the replaceable shear links, to study their inelastic seismic performance. The links exhibited a very good ductile behaviour, developing stable and repeatable yielding. Additional inelastic rotation capacity can be achieved with bolted replaceable links when allowing bolt bearing deformations to occur. The on-site replaceability of the link sections is confirmed even in the presence of residual deformations of 0.5% drift.

The threaded fasteners are one of the most versatile methods for assembly of structural components. For example, in bridges large bolts are used to fix base columns and small bolts are used to support access ladders. Naturally not all bolts are critical for the operation of the structure. Fasteners loaded with small forces and present in large quantities do not receive the same treatment as the critical bolts. Typical maintenance operations such tension measurements, internal stress checking or monitoring of crack development are not practical due to cost and time constrains. Although failure of a single non-critical fastener is not a significant threat to the structure's stability, massive malfunction may cause structural problem such as insufficient stiffness or excessive vibrations. The health of bolted joints is defined by a single parameter: the clamping force (CF). The CF is the force that holds the elements of the joint together. If the CF is too low, separation and bolt fatigue may occur. On the other hand, excessive CF may produce damages in the structural members such as excessive distortion or breakage. The CF is generated by the superposition of the individual tension of the bolts. The bolt tension, also referred as bolt preload, is the actual force that is stretching the bolt body. Maintaining the appropriate tension in bolts ensures a proper CF and hence a good health of the joint. In this thesis, a novel methodology for estimating the tension in bolts using surface acoustic waves (SAWs) is investigated. The tension is estimated by using the reflection of SAWs created by the bolt head interference. Increments in the bolt tension raise the points of interaction between the waves and the bolt head (real area of contact), and hence the position of the reflective boundaries. The variations are estimated using the "conventional linear synthetic array" imaging technique. A singular transducer is actuated from predefined positions to produce an array of signals that are subsequently arranged and added to construct an acoustic image. Three sets of experiment are presented in this research for validating the proposed concept: tension estimation of a ¼ inch stainless steel bolt, a ½ inch stainless steel bolt and ¼ inch grade 8 bolt. Acoustic images of the surface of the clamped plate illustrate a clear trend in the position of the reflective boundary when torque is changed. In all cases, the torque increments increase the real area of contact and therefore the position of the reflective boundary. As expected, the real area of contact grew from the bolt head center to the perimeter, which causes an effect of apparent movement of the boundary. This research proves the potential of the ultrasonic imaging methodology to measure applied tension. The result showed that the system can be used to successfully inspect tension in bolts of ½ and ¼ inches. The methodology investigated in this thesis is the first steps towards the development of bolt tension sensor based on surface acoustic waves.

Schlachtrinder werden in Deutschland gegenwärtig fast ausnahmslos mittels Bolzenschuss betäubt. Gründe dafür sind neben der guten Handhabbarkeit und Zuverlässigkeit der Geräte die hohe Betäubungssicherheit bei richtig gewähltem Ansatz des Gerätes am Kopf des Tieres. Dessen ungeachtet kommt es, durch menschliche als auch technische Fehler bedingt, immer wieder vor, dass Rinder nach dem ersten Schuss nicht oder nur unzureichend betäubt sind. Laut einschlägiger Literatur sind teilweise bis zu 32 % der Rinder von einer suboptimalen Betäubung betroffen, sowie bis zu 7 % von einer völlig fehlenden Betäubungswirkung nach dem ersten Schuss. Aus Sicht des Tier- als auch des Arbeitsschutzes ist es notwendig alle Tiere genauestens auf Anzeichen zu beobachten, die auf eine mangelhafte Betäubung oder auf ein Wiedererlangen der Wahrnehmungs- und Empfindungsfähigkeit hindeuten und diese Tiere gegebenenfalls nachzubetäuben. Ziel der vorliegenden Arbeit war es zu prüfen, ob eine Automatisierung der Betäubungsüberwachung mithilfe eines Wiegesystems möglich ist. Hierzu wurden Wiegezellen unter einer Betäubungsfalle installiert, um den Verlauf des Niederstürzens der Tiere nach erfolgter Betäubung aufzuzeichnen. Durch das zunächst ruckartige Anziehen der Gliedmaßen und das darauf folgende Zusammenbrechen der Tiere entsteht ein charakteristischer Gewichtskurvenverlauf, welcher mit der Betäubungsqualität korreliert wurde. Hierfür wurden umfangreiche Daten zur Betäubungseffektivität an 10.154 Jungbullen an einem kommerziellen Schlachtbetrieb erhoben und im Zusammenhang mit den aufgezeichneten Wiegeprotokollen ausgewertet. Herangezogen wurden zur Beurteilung des Betäubungserfolges sowohl bewährte Parameter (u. a. sofortiges Niederstürzen, negativer Corneal- bzw. Palpebralreflex und Verlust der regelmäßigen Atmung) als auch weniger übliche oder umstrittene Befunde, deren Aussagekraft geprüft werden sollte (u. a. Pupillenform, Zungen-, Ohr- und Schwanztonus, Restatemzüge und Reaktion auf Entblutestich). Anhand der insgesamt 21 erhobenen Befundparameter wurden die Tiere zum Zwecke der Auswertung in ein Schema eingeteilt. Demnach war die Betäubungswirkung nach dem ersten Schuss bei 0,3 % der Jungbullen fehlend, bei 1,8 % mangelhaft, bei 4,1 % fraglich und bei 7,4 % tadellos. 82,2 % der Tiere waren ausreichend betäubt, zeigten jedoch mindestens einen der zu prüfenden Befunde. Nachbetäubt wurden insgesamt 4,6 % der Rinder. Die zu prüfenden Parameter „keine runde, dilatierte Pupille“, „Pupille schlitzförmig“, „Ohrtonus“ und „deutliche Reaktion auf Entblutestich“ traten signifikant häufiger bei Tieren mit unzureichender Betäubungstiefe auf, während bei „Zungentonus“, „Schwanztonus“, „Restatemzügen“ und „deutlicher Erregung vor dem Schuss“ keine Korrelation erkennbar war. Die Ergebnisse zeigten auch, dass v. a. die Parameter „Schwanztonus“ und „aktives Hochziehen“ von verschiedenen Personen sehr subjektiv wahrgenommen wurden. Besondere Beachtung wurde dem Parameter „wiederkehrende regelmäßige Atmung“ geschenkt, da er erst zu einem relativ späten Zeitpunkt nach der Bolzenschussbetäubung auftritt. Eine solche wiederkehrende Atmung ca. 60 s nach der Betäubung trat bei 19 % der als unzureichend betäubt eingestuften Jungbullen sowie bei insgesamt 1,2 % aller untersuchten Tiere auf. 38 % dieser Tiere wies vorher bereits eine Bulbusrotation auf, sowie 22 % Nystagmus, während lediglich 4 % bzw. 2 % der Tiere ohne wiederkehrende Atmung diese Befunde zeigten. Zwischen der Länge des „stun-to-stick-Intervalls“ und dem Befund „wiederkehrende regelmäßige Atmung“ wurde kein verlässlicher Zusammenhang hergestellt. Nach den Ergebnissen dieser Untersuchung sind die Parameter „Zungentonus“, „Schwanztonus“, „Restatemzüge“, „deutliche Erregung vor dem Schuss“ und „aktives Hochziehen“ folglich wenig oder gar nicht aussagekräftig in Bezug auf die Betäubungsqualität. Im Gegensatz dazu sollte bei Bulbusrotation, Nystagmus und erhaltenem Ohrtonus eine sehr gewissenhafte weitere Beobachtung des Tieres bzw. eine „Sicherheits-Nachbetäubung“ erfolgen, um einem Wiederkehren der Wahrnehmungs- und Empfindungsfähigkeit des Rindes zuvorzukommen. Darüber hinaus scheint eine präzise Betäubung und sorgfältige Beobachtung der Tiere bis zum Ende der „Schwall-Entblutung“ zudem zielführender im Hinblick auf den Tierschutz als eine rigide Einhaltung des vorgeschriebenen „stun-to-stick-Intervalls“ von 60 s. Anhand der aufgezeichneten Wiegeprotokolle konnten 94 % der Tiere mit fehlender Betäubungswirkung bei einer Spezifität von 98 % korrekt als solche erkannt werden. Für Tiere mit mangelhafter Betäubungswirkung betrug die Sensitivität lediglich 49 %, bei einer Spezifität von 78 %. Nach den Ergebnissen der vorliegenden Arbeit ist das entwickelte Wiegesystem folglich zur Echtzeit-Analyse der Betäubungstiefe in dieser Form wenig geeignet, da Rinder mit gering ausgeprägten Anzeichen unzureichender Betäubungstiefe nicht mit ausreichend hoher Sensitivität und Spezifität erkannt werden konnten. Echte Fehlbetäubungen allerdings (kein Niederstürzen der Tiere beim ersten Betäubungsversuch) sind mithilfe des erläuterten Wiegesystems überwiegend gut identifizierbar. Eine kontinuierliche statistische Erfassung dieser Fehlbetäubungsrate, wie sie mit Beschluss 672/12 vom Bundesrat gefordert wird, wäre durch das entwickelte System daher möglich. / In Germany, slaughter cattle are stunned by captive bolt with almost no exceptions. Reasons for this are the good practicability and reliability of the (stunning) device, as well as the high stunning safety when a correct positioning of the device on the animal’s head is ensured. Due to human or technical faults it can still happen that cattle are not at all or not sufficiently stunned after the first shot. According to relevant literature, in some cases up to 32 % of the cattle are affected by suboptimal stunning, and up to 7 % by complete stunning failure at the first shot. Both from an animal welfare and working safety point of view, it is necessary to thoroughly monitor all animals for signs of insufficient stunning or recovery of consciousness and, if necessary, to re-stun them. The aim of this study was to determine if the monitoring of stunned cattle could be automated with the help of a weighing system. For this purpose, a weight scale was installed under the stunning box to plot the animals’ collapsing after the stun. The jerky lifting of the limbs and the following collapse create a characteristic weight curve, which was correlated to the stunning efficiency. For this purpose extensive data referring to the stunning efficiency were collected in 10,154 young bulls on a commercial slaughtering plant and interpreted in context with the recorded weight protocols. For the assessment of stunning efficiency, both established (e.g. immediate collapse, negative corneal- and palpebralreflex, cessation of rhythmic breathing) as well as less proved parameters (e.g. form of pupils, muscle tone of tongue, ears and tail, post stun exhalation, reaction to sticking), were used and the significance of the latter was investigated. On the basis of the 21 assessed parameters the animals were classified in a scheme for further analysis. According to this scheme, the stunning effect of the first shot was totally absent in 0.3 % of the young bulls, incomplete in 1.8 %, doubtful in 4.1 % and perfect in 7.4 %. 82.2 % of the animals were adequately stunned, but showed at least one of the parameters to be checked. In total 4.6 % of the cattle were re-stunned. The parameters “pupils not round and dilatated”, “pupils slit-like”, “ear muscle tone” and “clear reaction to sticking” appeared significantly more often in animals with imperfect concussion, while muscle tone of tongue and tail, post stun exhalation, and clear excitement before stunning could not be correlated with the stunning efficiency. The results showed also that the parameters “muscle tone of tail” and “lifting on the bleeding rail” in particular, were judged very subjectively between different persons. Special attention was paid to the parameter “regular breathing regained” as it occurs at a quite late stage after captive bolt stunning. Such recurring breathing about 60 s after stunning appeared in 19 % of young bulls classified as imperfectly stunned as well as in 1.2 % of all examined animals. Before regaining regular breathing, 38 % of these animals showed a rotation of the eye and 22 % showed nystagmus whereas only 4 % and 2 % respectively of the animals without recurring breathing showed these results. No reliable correlation was found between the length of the stun-to-stick intervals and the parameter “regular breathing regained”. According to the findings of this study the parameters “muscle tone of tongue and tail”, “post stun exhalation”, “clear excitement before stunning” and “lifting on the bleeding rail” are either not, or only slightly, conclusive as to the stunning efficiency. In contrast to that, there should be a very careful observation of the animals showing “rotation of the eye”, “nystagmus” or “ear muscle tone”, or a safety re-stun to prevent the cattle from regaining consciousness and sensibility. Furthermore a careful observation of the animals until the end of bleeding seems to be more important in terms of animal welfare than the rigid fulfilling of the prescribed stun-to-stick-interval of 60 s. With the help of the weight protocols, 94 % of the animals with absent stunning effect could be correctly identified, with a specificity of 98 %. For animals with incomplete stunning effect the sensitivity was only 49 %, with a specificity of 78 %. According to the results of this study, the developed system is not suitable in this form as a real-time-surveillance system to decide whether there should be a re-stun or not, as cattle with less distinctive signs of imperfect stunning efficiency could not be recognized with sufficiently high sensitivity and specificity. However, complete stunning failures (no collapse after first stun) are predominantly well detectable with the explained scale system. A continuous statistical recording of stunning failures, as demanded by the Bundesrat in the resolution (Beschluss) 672/12, would therefore be possible with the developed system.

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This study aims to validate a screw joint simulation model used by BAE Systems in LS-DYNA during blast simulations. It is important that the screw joint simulation model is physically correct, since the simulation results can influence major design decisions. The study provides a short overview on the subject of bolts and screws, material deformation and stress and strain in materials, of the finite element method (FEM) and on some specific numerical methods used in this study. BAE Systems started a validation project of the screw joint simulation model in 2015, but it was not finished due to other priorities. In this older project some drop-tower tests measuring the axial force in a screw joint were conducted. These old tests can now serve as validation data for the screw joint simulation model. The screw joint simulation model used by BAE Systems is dependent on a special kind of finite element formulation; a so called beam element. This study provides a finite element analysis on this simulation model, which is implemented through an established industry FEM solver called LS-DYNA. The validation of the screw joint simulation model is done against three drop-tower experiments performed at 900, 1000 and 1100mm drop height respectively. The drop-tower experiments were replicated in LS-DYNA, with a prescribed velocity on the falling parts rather than simulating a free fall and non-elastic impact. A comparison between the simulation model using beam elements, that is used by BAE Systems, and a similar simulation model using solid elements is presented as part of the validation. To make sure that the result of the study is confident, a local mesh convergence study and a study of the mass scaling numerical method in LS-DYNA is also presented. The results show that the screw joint simulation model using beam elements is valid according to the available experimental data. In one of the experiments, where the drop-test was performed twice, an average maximum force on the screw was measured to be 33.5+-4.8 kN. Simulations of the same case, under the same conditions, using beam elements resulted in a maximum force on the screw of 35.4 kN, well within the experimental result range. In the other two drop-tower experiments, the simulated results showed correlation considering the error sources in the simulation model and the statistical spread that is present in the experimental results. The simulation model using beam elements is also similar to the results using solid elements, which also indicates that the beam model is valid. All in all, it is shown that the beam model can be used to produce safe results that either overestimate or place the simulations of the axial force in the screw in the upper spread of the measurements.

Joints are the most critical elements in a steel framed structure. In most design guides or codes, the joints are assumed to a have higher fire resistance than the connected structural members because of the lower temperatures in the joints. However, in severe fire conditions, a connected beam's temperature may be higher than its limiting temperature and the beam may develop catenary action when the beam’s axial shortening from large deflections becomes greater than the beam’s thermal expansion. This beam catenary action force could fracture the joints, increasing the risk of progressive collapse. This research focuses on the interaction between joints and the connected steel beams and columns in steel framed structures in fire, including how the behaviour of a joint-beam assembly may be efficiently analyzed and how the joints may be constructed to achieve high degrees of catenary action. Three methods of simulating the joint behaviour in fire have been developed and implemented in the commercial finite element software ABAQUS. In the first modelling method, all structural members, including the connections, were simulated using detailed solid elements to enable detailed behaviour of the structure to be faithfully represented. In the second method, the columns were represented by conventional line (beam) elements, the joints were represented using springs (Connector Elements) based on the component based method, and the beam was modelled using solid elements. In the third method, the joints were modelled using springs as in the second method and the beam and columns were simulated using line (beam) elements. As expected, the detailed simulation method was extremely time-consuming, but was able to produce detailed and accurate results. The simulation results from the second and third methods contained some inaccuracies, but depending on the simulation objective, their simulation results may be acceptable. In particular, the third simulation method was very efficient, suitable for simulating complete frame structures under very large deflections in fire. The first method (detailed finite element method) was then used to investigate how to change the joint details to increase the survivability of restrained steel beams and beam-column assemblies at high temperatures since it enables detailed behaviour of the structure to be faithfully represented. It is found that by improving joint deformation capacity, in particular, using extended endplate connection with fire resistant bolts, very high temperatures can be resisted. The frame robustness in fire was investigated using the third simulation method to save computation time. The simulation structure was three-bay by three-floor and different scenarios of fire location, fire spread and initial structural damage were considered. The simulation results show that once failure of a column occurs, progressive collapse of the structure could be easily triggered and it would be rather futile to only enhance the joint capacity. Therefore, in addition to the measures of improving joint capacities (both rotation and strength), design of the affected columns should include consideration of the additional catenary forces from the connected beams and the increased effective lengths. Furthermore, the lateral bracing system should be ensured to provide the structure with lateral restraint.

Tunnels and anthropogenic underground cavities are a very natural part of our everyday modern life. Especially in larger cities such as Stockholm where the infrastructure reaches far above ground level as well as deep below the surface. Metro, commuter train, cars along with many other ways of transportation have been moved below the surface the last century. Before then there were neither the technology nor the knowledge of how tunnels and underground cavities should be constructed so that the safety is not neglected. Several different forces are present in the bedrock below us, such as the weight of the overlying rock/strata and stresses due to tectonic, thermal, or hydrostatic forces among other. Knowledge of these forces and stresses are essential so that you will not get a piece of rock falling on your head on your way home from work with the metro. In most of the cases the roof of tunnels or underground cavities are shaped like an arch, and the stability of these arches depends on several aspects. At excavation of rock, there are natural arches in the bedrock. However, the stability of these arches depends on stresses, amount of overlying rock and the presence of rock joints and fractures (amount, directions and the characteristics of rock joints and fractures are important). These among other aspects determine the stability and the size of the arch. The natural arch in a manmade underground cavity or tunnel is seldom sufficient for it to be safe enough for humans to be in. There is a need for reinforcement of different kinds, where rock bolting is one of the most common. This bachelor’s thesis used a model to simulate arches in tunnels and cavities. The model which simulated an arch was an uplifted box (820x820x250 mm) with railroad macadam, pressure gauges and systematically placed bolts (threaded rods with nuts and washers at each end). The bottom part of the uplifted box could be removed. With a torque wrench the macadam was subjected to different torques, and the bolts were then removed according to a pattern to see at which torques and stresses the model held. The purpose of the thesis was to develop a refined method for bolt model so that controlled experiments could be done. The purpose was as well to determine how important the stresses in the rock is for the span of the arch. The thesis should also function as an instruction for future experiments at the university.  According to the results of the experiments, both lower stresses and higher stresses gave rise to a large arch span. In many cases, an even stress distribution in the model resulted in a greater arch span, but in some cases not. More experiments would have to be done to reach a reliable result. Therefore, there is great potential for other students to continue these experiments. / Tunnlar och bergrum är i modern tid så vanliga att många knappt märker att en befinner sig i ett bergrum i sin vardag. Inte minst i större städer såsom Stockholm där infrastrukturen sträcker sig högt över markytan såväl som långt ner i berggrunden. Tunnelbana, biltrafik, tågtrafik är några transportsätt som ofta har förflyttats under jord det senaste århundradet. Innan dess fanns varken tekniken eller kunskapen om hur tunnlar och bergrum ska konstrueras för att säkerheten ska vara tillräckligt hög. I berget under oss finns det flera krafter som verkar, däribland vikten från ovanliggande berg, spänningar av tektoniska, termala eller hydrostatiska ursprung. Kunskap om dessa spänningar är väsentliga för att du inte ska få ett bergblock i huvudet när åker hem från jobbet med tunnelbanan. I de allra flesta fall har bergrummet eller tunneln ett tak format som ett valv, och stabiliteten av dessa valv beror på flera aspekter. När berguttag sker finns det en naturlig valvverkan som existerar i berget. Höga spänningar, mängden överliggande berg och förekomsten av sprickor (mängd, riktningar och egenskaper hos sprickorna) är några faktorer som påverkar stabiliteten av valvet och hur stort valvet kan vara. Den naturliga valvverkan i en antropogen tunnel är sällan tillräcklig för att valvet ska hålla och vara säkert för människor ska vistas i. Det krävs bergförstärkning av olika typer, där bultförstärkning är vanligt förekommande.  Arbetet gick ut på att simulera valv i berg med hjälp av en modell. Modellen efterliknar ett tunneltak och består av en upphöjd låda (820x820x250mm) med järnvägsmakadam, systematiskt placerade bultar (stänger med bricka och mutter i varje ände) och tryckmätare. Lådan har en avtagbar botten. Experimentet gick ut på att spänna upp makadammet med olika vridmoment, och se vid vilka moment det håller när bultarna succesivt tas bort i en viss ordning. Syftet med arbetet var att ta fram en förfinad metodik för bultmodell så att kontrollerade försök kan genomföras samt fastställa spänningars betydelse för spännvidd av valv. Uppsatsen ska även kunna användas som instruktion för framtida försök vid universitetet.  Resultatet visade att en stor spännvidd uppstod vid både höga och låga spänningar. En jämnare spänningsfördelning gav i flera fall en större spännvidd, men i andra fall inte. Fler försök hade behövt göras för att säkerställa ett pålitligt resultat och det finns därmed stor potential att bygga vidare på experimenten som gjorts.

The present Master thesis entitled "Engineering Design and Optimization of Injector Holder" deals with the design of clamping holder, whose function is to ensure the exact position of injector system Common Rail. The shape of the injector holder is designed in the modelling program, both with respect to the installation space of internal combustion engine and also the method of manufacture. The proposed geometry is then subjected to stress analysis in the program using FEM. The final design phase is to optimize the geometry of the injector holder using the same method with the aim to reduce the weight of the component.

The diploma thesis deal with design of a technological building in Ostrava serving for the sorting of slag to enagle its sequential use. Geometry of the structure was customized to technological requests. Static system was considered in two versions – joint connections with vertical bracing and omni-directional frame. For detail processing was chosen the joint one, besause it showed up as more advantageous. Static calculation was performed by Scia Engineer 14 software, then some typical connections and drawings were manually designed.