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Wind energy is one of the most promising sources of renewable energy worldwide. Its utilization has substantially increased for the last decades, both onshore and offshore. Offshore wind energy will have a lot to offer within the following decades, thus their foundations need to be prepared. Some of the current wind farms and wind turbines are now reaching their lifespan and, the turbines’ market is developing itself so rapidly that current turbines are getting behind the times with tremendous ease. It is here where the scope of this Master Thesis comes: what shall we do? Should we dismantle wind farms when they reach their lifespan, or should we maybe try to give them a further use? Accommodating for a new a larger wind turbine will need to account for new and higher climate actions and loads, namely winds, waves, ocean currents, the water level variation and the always difficult to predict ice actions. What is aimed in this Master Thesis is to set the basis for a procedure to dimension and define feasible solutions for the offshore wind turbines Gravity-Based Foundations to be expanded, avoiding the necessity of replacing them completely, with the environmental and economic benefits this would have. As this could turn to be an unmanageable problem to be solved, a Case Study where details can be set is performed at the Lillgrund Wind Farm site, in the south-west coast of Sweden, in the Öresund that separates Copenhagen and Malmö. A thorough description of the climatic actions and surrounding aspects is performed, while always dealing with uncertainties. With all that information, an analytical stability analysis is performed to account for three failure modes, namely: sliding, tilting andground failure. Additionally, a numerical FE-model is carried out in ANSYS in the aim of assessing the stresses and deformations that this kind of structure will suffer. Four alternatives are evaluated, and their behaviour is assessed based on the new external design actions. Analytical results show stability difficulties in two of the geometries inspected, while assure it in the other two. The FE-analyses show high concentrations of stresses on the GBS shaft, while model affordable deformations under the load combinations inspected. These results are also compared and contrasted in between them, and sensitivity analyses for the FE-models are performed in order to assure their good behaviour and development, and the trustworthiness ofthe results found. Based on these results, some conclusions are drawn from the developed processes. The main finding is the width and weight dependence of the solution, as well as the shape and dimensions. Future research needs such as scouring effects are finally accounted for necessary inspection to be made as continuation of the work here presented.

yes / This paper considers the importance of applying sound instructional systems design to the development of a learning intervention aimed at developing skills for the effective deployment of an enhanced methodology for engineering systems design analysis within a Product Development context. The leading features of the learning intervention are summarised including the content and design of a training course for senior engineering management which is central to the intervention. The importance of promoting behavioural change by fostering meaningful learning as a collaborative process is discussed. Comparison is made between the instructional design of the corporate learning intervention being developed and the systems engineering based product design process which is the subject of the intervention.

Plane strain deformations of an elastoplastic material are studied using numerical methods. In the first chapter, a meshless formulation of the static small strain elastic-plastic problem is formulated using the meshless local Petrov-Galerkin method. The code is validated against the small strain plasticity routines in the commercial finite element code ABAQUS for two basic configurations with loading, unloading, and reloading. The results are found to agree within 5%. The validated code is then used to analyze the stress intensity factor (SIF) in a double edge-cracked plate. Deformations of the plate are studied both with and without exploiting the symmetry conditions. The penalty method is used to enforce the essential boundary condition in the former case. When analyzing the deformations of the entire plate, the diffraction method is employed in order to introduce the discontinuity in the displacement field across the crack faces. The log-log and a higher order extrapolation technique due to Dally and Berger (1996) are used to calculate the SIF. It is found that the penalty method was inadequate to enforce the essential boundary conditions in the vicinity of the crack tip and that in this region the deformations were oscillatory. Consequently, the SIF calculation using the higher order technique was not accurate. It is also found that for a small plastic zone (3% of the cracked length) the SIFs do not differ significantly from their values for the corresponding linear elastic problem. In the second chapter, a finite element formulation of the dynamic deformations of a micro-porous thermoviscoplastic solid is formulated. The heat conduction in a material is assumed to be governed by a hyperbolic heat equation; thus thermal and mechanical waves propagate with finite speeds. The formation and propagation of an adiabatic shear band (ASB) inplane strain tensile deformations is studied for eleven materials. The ASB is assumed to form when the maximum shear stress has been reduced to 80% of its peak value at a point and it is deforming plastically. The materials are ranked according their susceptibility to the formation of an ASB. A parametric study of the effect of the initial defect strength where the defect is assumed through an initially inhomogeneous distribution of porosity, the thermal conductivity, the thermal wave speed, and the applied strain-rate upon the ASB initiation and propagation is conducted. It is found that the susceptibility ranking for this configuration differs somewhat from that previously found for simple shear and torsion of thin-walled tubes. It is also found that thermal conductivity influences ASB initiation and propagation only for materials with large values of · and that for such materials an adiabatic model may not be adequate. The effects of initial defect strength and the nominal strain-rates are both found to be consistent with simple shearing studies except that the ASB propagation speed was found to decrease with increasing nominal strain-rate. It is found that the criterion employed for ASB initiation accurately predicts the onset of the collapse of the total axial load applied to the body. In the final chapter, the formulation from the previous chapter is modified to permit the formation and propagation of brittle and ductile fracture. Deformations of the impact loaded double edge-crack specimen of Kalthoff and Winkler (1987) are studied. The brittle to ductile failure mode transition with increasing impact speed was found. Previous studies have focused on identifying the transition speed and did not allow for crack propagation. In this study, crack propagation is achieved through a nodal release algorithm and interpenetration of the crack surfaces is prevented using stiff-spring contact elements. Brittle fracture is assumed to occur when the maximum tensile principal stress achieves a critical value and the ductile fracture is assumed to occur when the effective plastic strain reaches a critical value. It is found that the transition speed for 4340 steel is approximately 54 m/s. For the brittle failure, the stress field is found to be significantly modified by the propagating crack and in the vicinity of the propagating crack the field is mode-I dominant. The crack formed through brittle fracture is found to completely propagate through the plate. For the ductile failure, the distribution of effective plastic strain about the crack tip is not significantly altered by the formation of the crack. The temperature rise in the vicinity of the ductile crack is found to be approximately 45% of the melting temperature of the material. / Ph. D.

Increasing interest, from the U.S. Army Corps of Engineers (USACE) and other agencies, in using deep-mixing methods (DMM) to improve the stability of levees constructed on soft ground is driven by the need to reduce levee footprints and environmental impacts and to allow for more rapid construction. Suitable methods for analysis and design of these systems are needed to ensure that the DMM technology is properly applied. DMM shear walls oriented perpendicular to the levee alignment are an effective arrangement for supporting unbalanced lateral loads. Shear walls constructed by overlapping individual DMM columns installed with single-axis or multiple axis equipment include vertical joints caused by the reduced width of the wall at the overlap between adjacent columns. These joints can be made weaker by misalignment during construction, which reduces the efficiency of the overlap. Depending on the prevalence and strength of these joints, complex failure mechanisms, such as racking due to slipping along vertical joints between adjacent installations in the shear walls, can occur. Ordinary limit equilibrium analyses only account for a composite shearing failure mode; whereas, numerical stress-strain analyses can account for other failure modes. Five case studies provided by the USACE were analyzed to evaluate the behavior of levee and floodwall systems founded on soft ground stabilized with DMM shear walls. These identified and illustrated potential failure mechanisms of these types of systems. Two-dimensional numerical stability and settlement analyses were performed for the case studies using the FLAC computer program. The key findings and conclusions for the individual case studies were assessed and integrated into general conclusions about design of deep-mixing support for levees and floodwalls. One of the significant findings from this research was to identify the potential for a partial depth racking failure, which can control design when the DMM shear walls are socketted into a relatively strong bearing layer. The potential for partial depth racking failure is not discussed in the literature and represents a new failure mode identified by this research. This discovery also highlights the importance of adapting suitable methods for analysis and design of these systems to address all potential failure modes. / Ph. D.

Fiber reinforced polymer (FRP) composites are considered very promising for infrastructure applications such as repair, rehabilitation and replacement of deteriorated bridge decks. However, there is lack of proper understanding of the structural behavior of FRP decks. For example, due to the localization of load under a truck tire, the conventionally used uniform patch loading is not suitable for performance evaluation of FRP composite deck systems with cellular geometry and relatively low modulus (compared to concrete decks). In this current study, a simulated tire patch loading profile has been proposed for testing and analysis of FRP deck. The tire patch produced significantly different failure mode (local transverse failure under the tire patch) compared to the punching-shear mode obtained using the conventional rectangular steel plate. The local response of a cellular FRP composite deck has been analyzed using finite element simulation and results are compared with full scale laboratory experiment of bridge deck and structure. Parametric studies show that design criteria based on global deck displacement is inadequate for cellular FRP deck and local deformation behavior must be considered. The adhesive bonding method is implemented for joining of bridge deck panels and response of structural joint analyzed experimentally. Strength, failure mode and fatigue life prediction methodologies for a cellular FRP bridge deck are presented in this dissertation. / Ph. D.

Water plays a critical role in every aspect of civilization: agriculture, industry, economy, environment, recreation, transportation, culture, and health. Much of America's drinking water and wastewater infrastructure; however, is old and deteriorating. A crisis looms as demands on these systems increase. The costs associated with renewal of these aging systems are staggering. There is a critical disconnect between the methodological remedies for infrastructure renewal problems and the current sequential or isolated manner of renewal analysis and execution. This points to the need for a holistic systems perspective to address the renewal problem. Therefore, new tools are needed to provide support for wastewater infrastructure decisions. Such decisions are necessary to sustain economic growth, environmental quality, and improved societal benefits. Accurate prediction of wastewater pipe structural and functional deterioration plays an essential role in asset management and capital improvement planning. The key to implementing an asset management strategy is a comprehensive understanding of asset condition, performance, and risk profile. The primary objective of this research is therefore to develop protocols and methods for evaluating the wastewater pipe performance. This research presents the life cycle of wastewater pipeline identifying the causes of pipe failure in different phases including design, manufacture, construction, operation and maintenance, and repair/rehabilitation/replacement. Various modes and mechanisms of pipe failure in wastewater pipes were identified for different pipe material which completed with results from extensive literature reviews, and interviews with utilities and pipe associations. After reviewing all relevant reports and utility databases, a set of standard pipe parameter list (data structure) and a pipe data collection methodology were developed. These parameters includes physical/structural, operational/functional, environmental and other parameters, for not only the pipe, but also the entire pipe system. This research presents a development of a performance index for wastewater pipes. The performance index evaluates each parameter and combines them mathematically through a weighted summation and a fuzzy inference system that reflects the importance of the various factors. The performance index were evaluated based on artificial data and field data to ensure that the index could be implemented to real scenarios. Developing a performance index led to the development of a probabilistic performance prediction model for wastewater pipes. A framework would enable effective and systematic wastewater pipe performance evaluation and prediction in asset management programs. / Ph. D.

No / Failure Mode and Effects Analysis (FMEA) is a proactive risk assessment tool used to identify potential vulnerabilities in complex, high-risk processes and to generate remedial actions before the processes result in adverse events. FMEA is increasingly used to proactively assess and improve the safety of complex health care processes such as drug administration and blood transfusion. A central feature of FMEA is that it is undertaken by a multidisciplinary team, and because it entails numerous analytical steps, it takes a series of several meetings. Composing a team of busy health care professionals with the appropriate knowledge, skill mix, and logistical availability for regular meetings is, however, a serious challenge. Despite this, information and advice on FMEA team assembly and meetings scheduling are scarce and diffuse and often presented without the accompanying rationale. The Multidisciplinary Team Assemble an eight-member team composed of clinically active health care staff, from every profession involved in delivery of the process—and who regularly perform it; staff from a range of seniority levels; outsider(s) to the process—and perhaps even to health care; a leader (and facilitator); and researchers. Scheduling Plan for 10–15 hours of team meeting time for first-time, narrowly defined FMEAs, scheduled as four to six meetings lasting 2 to 3 hours each, spaced weekly to biweekly. Meet in a venue that seats the team around one table and is off the hospital floor but within its grounds. Conclusions FMEA, generally acknowledged to be a useful addition to the patient safety toolkit, is a meticulous and time- and resource-intensive methodology, and its successful completion is highly dependent on the team members’ aptitude and on the facility’s and team members’ commitment to hold regular, productive meetings.

No / Objectives: To empirically compare 2 different commonly used failure mode and effects analysis (FMEA) scoring procedures with respect to their resultant failure mode scores and prioritization: a mathematical procedure, where scores are assigned independently by FMEA team members and averaged, and a consensus procedure, where scores are agreed on by the FMEA team via discussion. Methods: A multidisciplinary team undertook a Healthcare FMEA of chemotherapy administration. This included mapping the chemotherapy process, identifying and scoring failure modes (potential errors) for each process step, and generating remedial strategies to counteract them. Failure modes were scored using both an independent mathematical procedure and a team consensus procedure. Results: Almost three-fifths of the 30 failure modes generated were scored differently by the 2 procedures, and for just more than one-third of cases, the score discrepancy was substantial. Using the Healthcare FMEA prioritization cutoff score, almost twice as many failure modes were prioritized by the consensus procedure than by the mathematical procedure. Conclusions: This is the first study to empirically demonstrate that different FMEA scoring procedures can score and prioritize failure modes differently. It found considerable variability in individual team members' opinions on scores, which highlights the subjective and qualitative nature of failure mode scoring. A consensus scoring procedure may be most appropriate for FMEA as it allows variability in individuals' scores and rationales to become apparent and to be discussed and resolved by the team. It may also yield team learning and communication benefits unlikely to result from a mathematical procedure.

Riskanalysverktyget failure mode and effects analysis (FMEA) som analyserar kompo-nenter och signaler är beroende av att designen av fordonets elsystem finns tillgängligt och utförs därför sent i utvecklingsprocessen av elsystem. Detta medför att vissa fel inte analyseras i tid och kanske måste designas bort i efterhand vilket kan leda till ökad sy-stemkomplexitet samt längre och dyrare utvecklingsprocesser.Målet med examensarbetet är att genom en litteraturstudie ta reda på om det finns me-toder eller arbetssätt som gör att Scania tidigt i utvecklingsprocessen av elsystem kan genomföra funktionsanalyser i sitt riskanalysarbete med FMEA samt analysera dessa.Resultatet av detta examensarbete visar att det är möjligt att påbörja FMEA-arbetet tidigt i utvecklingsprocessen av elsystem om ingenjörerna utgår från ett funktionsperspektiv i riskanalysarbetet där de listar och rangordnar de funktioner som tillsammans realiserar en eller flera funktionaliteter samt deras felmoder, feleffekter, feldetektering, allvarlighet, sannolikhet och frekvens. Med hjälp av en FFMEA kan ingenjörerna tidigt i utveck-lingsprocessen av elsystem snabbt och effektivt hantera de identifierade säkerhetskritiska funktionerna.En befintlig funktionalitet på Scania har brutits ned i funktioner och en FFMEA har genomförts på dessa som en demonstration på hur en FFMEA kan genomföras och se ut. / The risk analysis tool failure mode and effects analysis (FMEA) that analyzes the com-ponents and signals of a electrical system is design dependent and are therefore per-formed late in the development process of electrical systems. This could lead to that some errors are not analyzed in time and may need to be designed away which can lead to increased system complexity as well as longer and more expensive development proc-esses.The objective of this study is that through a literature review identify if there are any methods or approaches that enables Scania to implement a functional hazard analyzes early in the development process of electrical systems and to analyze these.The results of this thesis shows that it is possible to start the FMEA process early in the development process of the electrical system if the engineers have a functional perspec-tive in mind when performing the risk analysis where they list and rank the functions that is provided by the electrical system and their failure modes, failure effects, failure de-tection, severity, probability and occurrence.By using a function based FMEA, the engineer(s) can identify and promptly handle the safety critical functions early in the development process of a electrical system.A existing functionality at Scania has been broken down into functions and a functional hazard analysis has been performed on these as a demonstration of how a function based FMEA can be carried out and look like.