The demands on maritime operations today are increasingly higher in terms of control, efficiency and cost. The margins for accidents and security incidents are therefore decreasing. In the area of ship safety the regulations, guidelines and methods have a history and culture of systematic research, development and implementation. In contrast, international security is highly politicized and therefore not as transparent. The result is that a tradition of ship security is not as well established. The overall aim of this thesis is to propose a method for ship security analysis that increases the overall safety of the crew and the ship. The objective is to develop a method that is systematic in order to ensure that assessment and response are complete and effective, and that the process is documented to provide evidence of decision-making. The method used is probabilistic risk assessment where quantitative analysis is central. The proposed approach is consistent with the requirements of maritime safety work. However, in the work here, the proposed methods are specifically tested for security cases. This is because hazards (without intent) and threats (with intent) evolve in different ways into risk. Therefore, they must be analysed differently in order to capture the causal relationship. The proposed approach consists of three steps: the first step consists of a threat description that documents qualitative and quantitative aspects that together describe how the threat most likely will act in relation to the ship’s vulnerability; the second step uses the threat description to define the system studied as well as the scenarios that collectively describe the harmful consequences; the third step evaluates the risk with tools from probabilistic risk assessment. The overall conclusion is that the proposed method brings the procedure and results of ship security analysis into the open and therefore allows for criticism, improvements and shared risk knowledge, not possible with less structured methods. The results also show that the calculated probabilities agree with available statistics, which indicates that the analysis succeeds in describing the central causal relationships of the scenarios modelled.

Föreliggande avhandlings centrala syfte är att undersöka säkerhetskultur ombord i fartyg vilka trafikerar Östersjön. Genomgående för fartyg i Östersjöfart är täta hamnanlöp, kustnära resor, trafik i tätt trafikerade områden samt små besättningar. Tidigare forskning antyder att det kan finnas ett systemfel i sjöfarten. Charles Perrow beskriver, till exempel, sjöfarten som ett felskapande system och menar att orsaken till detta är hur sjöfarten bedrivs. James Reason menar att värdering, attityd, kompetens och beteendemönster är fyra viktiga parametrar som definierar en säkerhetskultur. Sjöfartens säkerhetsstyrningssystem, International Safety Management Code (ISM) syftar till att en proaktiv och utvecklande säkerhetskultur skapas och upprätthålls inom sjöfarten. Resultaten av den här studien visar att sjöfarten saknar en framförhållning, ”failure of foresight”, där det proaktiva arbetssättet syftar till att incidenter och olyckor kan förutses. Studien har ett etnografiskt perspektiv vilket syftar till att skapa en så fullödig beskrivning över den kultur som studeras. Totalt ingår elva olika fartyg i studien, där besöken ombord varierat från någon timme till ett par dagar. Insamlad data har via en egenutvecklad analysmodell bearbetats för att försöka förklara säkerhetskulturen. I fokus i analysmodellen står hur information, feedback, ansvar, samarbete, uppföljning samt utveckling hanteras. Studien visar att det finns behov av att diskutera och förändra säkerhetskulturen i sjöfarten, både i stort som enskilt i fartygen. Det finns ett behov av vidare studier av hur säkerhetskulturen kan förbättras, samt ett behov av riktade utbildningsinsatser inom systemtänkande, organisationsteori och säkerhetskultur. / The main purpose of this thesis is to explore the safety culture onboard vessels trading in the Baltic Sea. The common denominator for vessels trading in the Baltic Sea is frequent port visits, coastal voyages, voyages in dense trafficked areas and small crews. Earlier research shows that there may be a system fault in the shipping industry. Charles Perrow describes the maritime industry as an error inducing system. He means that the cause for that is the way shipping is carried out. In a safety culture values, attitudes, competence and behavioral patterns are four important factors that define the safety culture. The maritime safety management system, International Safety Management Code (ISM) aims towards a proactive and evolutionally safety culture in the shipping industry. The results show that shipping today lacks a foresight, “failure of foresight”, where the proactive way of work leads to incidents and accidents being anticipated. This study has an ethnographic perspective, which aims to create a thick and substantial description of the culture that is being studied. Totally a number of eleven vessels participated in the study. The visits onboard reach from a couple of hours up to a few days. Collected data has been analysed through a self-developed model in an ambition to try to explain the safety culture. The model focuses on how information, feedback, responsibility, co-operation, follow-up and development are being handled. The study reveals that there is a need to discuss and change the safety culture in the shipping industry, in large as on the single vessel. As well as a need for further studies of how the safety culture can be improved and a need for education aimed towards system thinking, organizational theory and safety culture.

The accuracy in determined energy consumption and runningtime of trains, by means of computer simulation, is dependent upon the various models used. This thesis aims at developing validated models of running resistance, train and of a generaldriver, all based on full scale testing. A partly new simple methodology for determining running resistance, called by energy coasting method is developed and demonstrated. An error analysis for this methodis performed. Running resistance of high speed train SJ X2000, conventional loco hauled passenger trains and freight trains is systematically parameterised. Influence of speed, number of axles, axle load, track type, train length,and train configuration is studied. A model taking into account the ground boundary layer for determining the influence ofmeasured head and tail wind is developed. Different factors and parameters of a train, that are vital for the accuracy in computed energy consumption and runningtime are identified, analysed and finally synthesized into a train model. Empirical models of the braking and the traction system, including the energy efficiency, are developed for the electrical locomotive of typeSJ Rc4, without energy regeneration. Driver behaviour is studied for freight trains and a couple of driving describing parametersare proposed. An empirical model of freight train driver behaviour is developed from fullscale testing and observations. A computer program, a simulator, is developed in Matlabcode, making use of the determined runningresistance and the developed models of train and driver. The simulator calculates the energy consumption and running time ofa single train. Comparisons between simulations and corresponding measurements are made. Finally, the influence of driving on energy consumption and running time is studied and demonstrated in some examples. The main conclusions are that: The method developed for determining running resistanceis quite simple and accurate. It can be used on any train andon any track. The running resistance of tested trains includes some interesting knowledge which is partly believed to be new. Mechanical running resistance is less than proportional to the actual axle load. Air drag increases approximately linearly with train length and the effect of measured head and tail wind on the air drag can be calculated if the groundboundary layer is considered. The developed train model, including running resistance, traction, braking etc. is quite accurate, as verified for the investigated trains. The driver model together with the train model insimulations, is verified against measurements and shows good agreement for energy consumption and running time. It is recommended to use a driver model, when calculating energy consumption and running times for trains. Otherwise, the energy consumption will most likely be over-estimated.This has been demonstrated for Swedish ordinary freighttrains. / QC 20100526

Multidisciplinary design optimization (MDO) can be used in computer aided engineering (CAE) to efficiently improve and balance performance of automotive structures. However, large-scale MDO is not yet generally integrated within automotive product development due to several challenges, of which excessive computing times is the most important one. In this thesis, a metamodel-based MDO process that fits normal company organizations and CAE-based development processes is presented. The introduction of global metamodels offers means to increase computational efficiency and distribute work without implementing complicated multi-level MDO methods. The presented MDO process is proven to be efficient for thickness optimization studies with the objective to minimize mass. It can also be used for spot weld optimization if the models are prepared correctly. A comparison of different methods reveals that topology optimization, which requires less model preparation and computational effort, is an alternative if load cases involving simulations of linear systems are judged to be of major importance. A technical challenge when performing metamodel-based design optimization is lack of accuracy for metamodels representing complex responses including discontinuities, which are common in for example crashworthiness applications. The decision boundary from a support vector machine (SVM) can be used to identify the border between different types of deformation behaviour. In this thesis, this information is used to improve the accuracy of feedforward neural network metamodels. Three different approaches are tested; to split the design space and fit separate metamodels for the different regions, to add estimated guiding samples to the fitting set along the boundary before a global metamodel is fitted, and to use a special SVM-based sequential sampling method. Substantial improvements in accuracy are observed, and it is found that implementing SVM-based sequential sampling and estimated guiding samples can result in successful optimization studies for cases where more conventional methods fail.

Kongsberg Automotive is developing a brand-new actuator for engaging and disengaging a clutch for different driveline applications. This master thesis research improves the concept design of the shift fork for the new Dog-Clutch Actuator using Design for Manufacturability (DFM). Initially, the knowledge about the mechanism of the product is gained with the aid of the design team and the proper boundary conditions for the boundary value problem are obtained. The conventional die-cast materials are investigated, and appropriate material is selected to create the material model. Most of the traditional HPDC aluminum alloys are aluminum-silicon system; therefore, a detailed study on the nucleation of Silicon in the melt and how it influences the mechanical properties of the alloy is conducted. During gear engagement, the two rotating gears of the dog-clutch collide and synchronize the angular velocity of the hub and the input gear. The synchronization force is dynamic; therefore, explicit time integration is used to capture the system's response with the assistance of FEM software. As the shift fork undergoes cyclic load during the gear shift, the fatigue analysis is performed to evaluate the life (Nf) of the component using Wohler's curve. The value of the maximum principal stress at the critical spots like notch and its direction are determined using the 3D Mohr's circle. In this analysis, the endurance limit correction factors and notch factor (Kf) are used for the S-N curve correction, and Goodman's criteria are used to incorporate the mean stress effect. Fatigue analysis requires a very fine mesh to estimate the precise stress magnitude at the critical locations and, the structural optimization algorithm requires many iterations to determine the optimal layout of the shift fork. Therefore, the explicit integration scheme is not efficient as it will be computationally expensive and time-consuming to solve the problem. Hence, the equivalent static load is determined for the gear shift force at the peak load and used for calculations and product development. As the initial concept design of the shift fork is asymmetrical, it requires varying stiffness in its structure to transfer the force efficiently to the shift sleeve. The FEA results state that one prong of the shift fork experience up to 75% of the total load, which increases the overall stress of the component (up to 0.9Sy). The shift fork also doesn't have adequate torsional stiffness, and as a result, stress concentration has occurred in one of the fillets in the shift fork. The iterative design is set up to improve the design of the shift fork by optimizing the stiffness of the two prongs which provided the key observations that describe the design changes which improved the design. In this phase, the overall stress of the component is reduced by 20% and minimizes the difference in the load between the two prongs by 27.5% compared to the initial design. The shift fork needs to be light to achieve the necessary acceleration during the gear shift. Therefore, topology optimization using the projected subgradient method is implemented to optimize the mass and compliance of the improved design in the iterative design phase. Then the design realization phase is set up to implement the results obtained from the topology optimization to conceptualize the viable product. The optimized result decreased the overall stress and maximum deflection by 20%. It also reduced the load difference in the two prongs of the shift fork by 35% by maintaining the same mass as the initial concept design.

An emerging technology is the hybridization of wheel loaders. Since wheel loaders commonly operate in repetitive cycles it should be possible to use this information to develop an efficient energy management strategy that decreases fuel consumption. The purpose of this thesis is to evaluate if and how this can be done in a real-time online application. The strategy that is developed is based on pattern recognition and Equivalent Consumption Minimization Strategy (ECMS), which together is called Adaptive ECMS (A-ECMS). Pattern recognition uses information about the repetitive cycles and predicts the operating cycle, which can be done with Neural Network or Rule-Based methods. The prediction is then used in ECMS to compute the optimal power distribution of fuel and battery power. For a robust system it is important with stability implementations in ECMS to protect the machine, which can be done by adjusting the cost function that is minimized. The result from these implementations in a quasistatic simulation environment is an improvement in fuel consumption by 7.59 % compared to not utilizing the battery at all.

Heat transfer plays an important role in affecting an on-engine turbocharger performance. However, it is normally not taken into account for turbocharged engine simulations. Generally, an engine simulation based on one-dimensional gas dynamics uses turbocharger performance maps which are measured without quantifying and qualifying the heat transfer, regardless of the fact that they are measured on the hot-flow or cold-flow gas-stand. Since heat transfer situations vary for on-engine turbochargers, the maps have to be shifted and corrected in the 1-D engine simulation, which mass and efficiency multipliers usually do for both the turbine and the compressor. The multipliers change the maps and are often different for every load point. Particularly, the efficiency multiplier is different for every heat transfer situation on the turbocharger. The heat transfer leads to a deviation from turbocharger performance maps, and increased complexity of the turbocharged engine simulation. Turbochargers operate under different heat transfer situations while they are installed on the engines. The main objectives of this thesis are: heat transfer modeling of a turbocharger to quantify and qualify heat transfer mechanisms, improving turbocharged engine simulation by including heat transfer in the turbocharger, assessing the use of two different turbocharger performance maps concerning the heat transfer situation (cold-measured and hot-measured turbocharger performance maps) in the simulation of a measured turbocharged engine, prediction of turbocharger walls’ temperatures and their effects on the turbocharger performance on different heat transfer situations. Experimental investigation has been performed on a water-oil-cooled turbocharger, which was installed on a 2-liter GDI engine for different load points of the engine and different heat transfer situations on the turbocharger by using insulators, an extra cooling fan, radiation shields and water-cooling settings. In addition, several thermocouples have been used on accessible surfaces of the turbocharger to calculate external heat transfers. Based on the heat transfer analysis of the turbocharger, the internal heat transfer from the bearing housing to the compressor significantly affects the compressor. However, the internal heat transfer from the turbine to the bearing housing and the external heat transfer of the turbine housing mainly influence the turbine. The external heat transfers of the compressor housing and the bearing housing, and the frictional power do not play an important role in the heat transfer analysis of the turbocharger. The effect of the extra cooling fan on the energy balance of the turbocharger is significant. However, the effect of the water is more significant on the external heat transfer of the bearing housing and the internal heat transfer from the bearing housing to the compressor. It seems the radiation shield between the turbine and the compressor has no significant effect on the energy balance of the turbocharger. The present study shows that the heat transfer in the turbocharger is very crucial to take into account in the engine simulations. This improves simulation predictability in terms of getting the compressor efficiency multiplier equal to one and turbine efficiency multiplier closer to one, and achieving turbine outlet temperature close to the measurement. Moreover, the compressor outlet temperature becomes equal to the measurement without correcting the map. The heat transfer situation during the measurement of the turbocharger performance influences the amount of simulated heat flow to the compressor. The heat transfer situation may be defined by the turbine inlet temperature, oil heat flux and water heat flux. However, the heat transfer situation on the turbine makes a difference on the required turbine efficiency multiplier, rather than the amount of turbine heat flow. It seems the turbine heat flow is a stronger function of available energy into the turbine. Of great interest is the fact that different heat situations on the turbocharger do not considerably influence the pressure ratio of the compressor. The turbine and compressor efficiencies are the most important parameters that are affected by that. The component temperatures of the turbocharger influence the working fluid temperatures. Additionally, the turbocharger wall temperatures are predictable from the experiment. This prediction enables increased precision in engine simulations for future works in transient operations. / QC 20120504

In this thesis, the in-duct experimental methods for determining aeroacoustic N-ports of in-duct elements are discussed and improved. The scattering matrix determination methods and the related wave decomposition methods are evaluated from measurements in an empty duct carrying a mean flow. The improvements of a new over-determination method for the source part of the N-port is studied using simulations and measurements; in quiescent air as well as measurements of the flow associated noise of a mixer plate, here a triangular plate inserted at an angle in a duct. The new method is shown to improve suppression of random errors while no improvement is achieved for bias errors.   Further, the methods are applied in the study of two different aeroacoustic phenomena; one is the effect on the flow associated noise of the triangular plate achieved by varying the bending stiffness. For the most resilient plate tested, it is observed that when the Strouhal number of the flow noise coalesce with the Helmholtz number of a specific eigen-mode of the plate, the noise is drastically dampened. There is also a weaker broad band effect.   The other phenomena studied is the amplification and attenuation obtained for sound waves propagating in a T-junction of rectangular ducts. It is found that by adding only 10% of inflow in the side branch relative to that in the main branch, the amplification is heavily increased. By adding another 10% the amplification is again similar to that of no side branch flow. Adding further flow lessens the effects still. / QC 20101118 / Experimental characterization of aero-acoustic sources

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature. / Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

High speed in waves, necessary in for instance rescue or military operations, often result in severe loading on both the craft and the crew. To maximize the performance of the high-speed craft (HSC) system that the craft and crew constitute, balance between these loads is essential. There should be no overload or underuse of crew, craft or equipment. For small high-speed craft systems, man is often the weakest link. The human exposure to vibration and shock results in injuries and other adverse health effects, which increase the risks for non-safe operations and performance degradation of the crew and craft system. To achieve a system in balance, the human acceleration exposure must be considered early in ship design. It must also be considered in duty planning and in design and selection of vibration mitigation systems. The thesis presents a simulation-based method for prediction and evaluation of the acceleration exposure of the crew on small HSC. A numerical seat model, validated with experimental full-scale data, is used to determine the crew's acceleration exposure. The input to the model is the boat acceleration expressed in the time domain (simulated or measured), the total mass of the seated human, and seat specific parameters such as mass, spring stiffness and damping coefficients and the seat's longitudinal position in the craft. The model generates seat response time series that are evaluated using available methods for evaluation of whole-body vibration (ISO 2631-1 \&amp; ISO 2631-5) and statistical methods for calculation of extreme values. The presented simulation scheme enables evaluation of human exposure to vibration and shock at an early stage in the design process. It can also be used as a tool in duty planning, requirements specification or for design of appropriate vibration mitigation systems. Further studies is proposed within three areas: investigation of the actual operational profiles of HSC, further development of seat models and investigation of the prevailing injuries and health problems among the crew of HSC. / <p>QC 20150126</p>