This thesis focuses on practical and quantitative methods for measuring effectiveness in naval ship design. An Overall Measure of Effectiveness (OMOE) model or function is an essential prerequisite for optimization and design trade-off. This effectiveness can be limited to individual ship missions or extend to missions within a task group or larger context. A method is presented that uses the Analytic Hierarchy Process combined with Multi-Attribute Value Theory to build an Overall Measure of Effectiveness and Overall Measure of Risk function to properly rank and approximately measure the relative mission effectiveness and risk of design alternatives, using trained expert opinion to replace complex analysis tools. A validation of this method is achieved through experimentation comparing ships ranked by the method with direct ranking of the ships through war gaming scenarios. The second part of this thesis presents a mathematical ship synthesis model to be used in early concept development stages of the ship design process. Tools to simplify and introduce greater accuracy are described and developed. Response Surface Models and Design of Experiments simplify and speed up the process. Finite element codes such as MAESTRO improve the accuracy of the ship synthesis models which in turn lower costs later in the design process. A case study of an Advanced Logistics Delivery Ship (ALDV) is performed to asses the use of RSM and DOE methods to minimize computation time when using high-fidelity codes early in the naval ship design process. / Master of Science

In this work minimally supported D-optimal designs for response surface models with spatially correlated errors are studied. The spatially correlated errors describe the correlation between two measurements depending on their distance d through the covariance function C(d)=exp(-rd). In one dimensional design space, the minimally supported D-optimal designs for polynomial models with spatially correlated errors include two end points and are symmetric to the center of the design region. Exact solutions for simple linear and quadratic regression models are presented. For models with third or higher order, numerical solutions are given. While in two dimensional design space, the minimally supported D-optimal designs are invariant under translation¡Brotation and reflection. Numerical results show that a regular triangle on the experimental region of a circle is a minimally supported D-optimal design for the first-order response surface model.

No description available.

Nine independent and four dependent variables are used to build a response surface to calculate strip crown using the difference in the industry standard strip height measurements. The single element response surface in use provides the advantages of continuous derivatives and decouples rolling load from the determination of exit height. The data points to build the response surface are the product of a calibrated finite element model. The rolling dynamics in the finite element model creates a transient that requires nonlinear regression to find the system steady-state values. Weighted-least squares is used to build a response surface using isoparametric interpolation with the non-rectangular domain of the mill stands represented as a single element. The regression statistics, the 1-D projections, comparisons against other response surface models and the comparisons against an existing strip crown model are part the validation of the response surface generated. A four-high mill stand is modeled as a quarter-symmetry 3-D finite element model with an elastic-plastic material model. A comparison of the pressure distribution under the arc of contact with existing research supports the pressure distribution found with experiments conducted by Siebel and Lueg [16] and it also suggests the need for one improvement in the initial velocity for the strip in the finite element model. The strip exit heights show more sensitivity to change than strip exit crown in seven out of the nine independent variables, so a response surface built with the strip exit height is statistically superior to using the derived dependent variable strip exit crown. Sensitivity of strip exit crown and the strip exit heights to changes in work-roll crown are about equal. Backup-roll diameter sensitivity is small enough that oversampling for the mean trend has to be considered or ignore backup-roll altogether. Strip entry velocity is a new independent variable, unless the response surface is built from the derived variable, strip exit crown. A problem found is that the sensitivity of strip entry crown and work-roll crown requires a larger than typical incremental change to get a reliable measure of the change strip exit crown. A narrow choice of high and low strip entry crowns limits the usefulness of the final response surface. A recommendation is to consider the use of the strip cross-section as an exit crown predictor. / Master of Science

The purpose of this research is to investigate the influence of stitching architectures by using different stitching periodic patterns on the in-plane and out-of-plane mechanical properties. By using the inherent periodic architecture of these composites, their mechanical properties may be tailored for specific applications. Composite structures are extensively used in several industries such as aerospace, automotive, sports, and construction due to their many advantages, which include tailorable mechanical properties, high strength-to-weight ratios, and high specific stiffness. However, due to their low interlaminar tensile strength, composites are prone to delaminations, which can degrade the overall mechanical performance of the structure. Through-thickness stitching provides the third-direction reinforcement to enhance the interlaminar tensile and shear strengths. In this study, quasi-isotropic composite test articles were manufactured and stitched through-thickness using different chain stitch patterns. Full-field surface strain measurements were collected through the non-contact digital image correlation (DIC) technique. A design of experiments (DoE) approach was used to investigate the stitch parameters, such as stitch density (number of stitches per unit area), stitch angle (stitch seam orientation), and linear thread density (thread diameter), and their interactions on the in-plane and out-of-plane mechanical properties. Experimental results are then used to develop a statistically informed response surface model (RSM) to find optimal stitching parameters based on a maximum predicted tensile strength, tensile modulus and flexural strength.

Liquid chromatography (LC) coupled to mass spectrometry (MS) offers highly selective and sensitive analysis of a wide variety of compounds. However, the use of hyphenated experimental set-ups implies that many parameters may have an effect on the studied response. Therefore, in order to determine optimized experimental conditions it is of vital importance to incorporate systematic procedures during method development. In this thesis, a generic stepwise optimization strategy is proposed that aims at high chromatographic quality, as well as high mass spectrometric response. The procedure comprises (i) screening experiments to identify the most important parameters, (ii) LC studies to ensure sufficient chromatographic separation, (iii) extended infusion experiments in order to maximize precursor signal(s), and in the case of tandem MS (iv) extended infusion experiments to determine optimal conditions for collision induced dissociation and when applicable also ion trap settings. Experimental design and response surface methodology is used throughout the procedure. Further, the general applicability of LC-MS is demonstrated in this thesis. Specifically, a novel quantitative column-switched LC-MS method for ferrichrome, ferrichrysin and ferricrocin determination is presented. Using the method it was shown how the siderophore content varies with depth in podzolic soil profiles in the north and south of Sweden. The parallel approach using LC coupled to both inductively coupled plasma (ICP) mass spectrometry, and electrospray ionization (ESI) tandem MS is also evaluated as a tool to identify unknown siderophores in a sample. Additionally, different trypsin digestion schemes used for LC-ESI-MS peptide mapping were compared. By multivariate data analysis, it was clearly shown that the procedures tested induce differences that are detectable using LC-ESI-MS. Finally, the glutathione S-transferase catalyzed bioactivation of the prodrug azathioprine was verified using LC-MS.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A identificação de danos estruturais é uma questão de fundamental importância na engenharia, visto que uma estrutura está sujeita a processos de deterioração e a ocorrência de danos durante a sua vida útil. A presença de danos compromete o desempenho e a integridade estrutural, podendo colocar vidas humanas em risco e resultam em perdas econômicas consideráveis. Técnicas de identificação de danos estruturais e monitoramento de estruturas fundamentadas no ajuste de um Modelo de Elementos Finitos (MEF) são constantes na literatura especializada. No entanto, a obtenção de um problema geralmente mal posto e o elevado custo computacional, inerente a essas técnicas, limitam ou até mesmo inviabilizam a sua aplicabilidade em estruturas que demandam um modelo de ordem elevada. Para contornar essas dificuldades, na formulação do problema de identificação de danos, pode-se utilizar o Modelo de Superfície de Reposta (MSR) em substituição a um MEF da estrutura. No presente trabalho, a identificação de danos estruturais considera o ajuste de um MSR da estrutura, objetivando-se a minimização de uma função de erro definida a partir das frequências naturais experimentais e das correspondentes frequências previstas pelo MSR. Estuda-se o problema de identificação de danos estruturais em uma viga de Euler-Bernoulli simplesmente apoiada, considerando as frequências naturais na formulação do problema inverso. O comportamento de uma viga de Euler-Bernoulli simplesmente apoiada na presença de danos é analisado, com intuito de se verificar as regiões onde a identificação dos mesmos pode apresentar maior dificuldade. No processo de identificação de danos, do presente trabalho, são avaliados os tipos de superfícies de resposta, após uma escolha apropriada do tipo de superfície de resposta a ser utilizado, determina-se a superfície de resposta considerando os dados experimentais selecionados a partir do projeto ótimo de experimentos. A utilização do método Evolução Diferencial (ED) no problema inverso de identificação de danos é considerado inerente aos resultados numéricos obtidos, a estratégia adotada mostrou-se capaz de localizar e quantificar os danos com elevada acurácia, mostrando a potencialidade do modelo de identificação de danos proposto. / The identification of structural damage is an issue of fundamental importance in engineering, since a structure is subject to deterioration processes and to the occurrence of damage throughout its useful lifetime. The presence of damage compromises the performance and structural integrity, may put human lives at risk and may result in considerable economic losses. Damage identification and structural health monitoring techniques built on Finite Element Model (FEM) updating are constant in the specialized literature. However, the problem generally rank deficient and the high computational cost, inherent to these techniques, limit or even render their applicability in structures that require a high order model. To circumvent these difficulties, in the formulation of the damage identification problem, one may use a Response Surface Model (RSM) in place of a FEM of the structure. In the present work, the identification of structural damage considers the update of a RSM of the structure, with the aim at minimizing an error function defined from the experimental natural frequencies and the corresponding natural frequencies prescribed by a RSM. The problem of structural damage identification in a simply supported Euler-Bernoulli beam is studied, taking into account the natural frequencies in the inverse problem formulation. The behavior of a simply supported Euler-Bernoulli beam, in the presence of damage, is analyzed, in order to verify the identification of regions where the damage identification may present greater difficulties. In the damage identification process, in the present work, after a suitable choice of the type of the response surface model, the surface model is derived considering the experimental data selected from an optimal design of experiments. The use of the Differential Evolution (DE) method in the inverse problem of damage identification is considered. Considering the numerical results obtained, the strategy adopted proved to be able to locate and quantify the damage with high accuracy, showing the capability of the proposed damage identification model.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A identificação de danos estruturais é uma questão de fundamental importância na engenharia, visto que uma estrutura está sujeita a processos de deterioração e a ocorrência de danos durante a sua vida útil. A presença de danos compromete o desempenho e a integridade estrutural, podendo colocar vidas humanas em risco e resultam em perdas econômicas consideráveis. Técnicas de identificação de danos estruturais e monitoramento de estruturas fundamentadas no ajuste de um Modelo de Elementos Finitos (MEF) são constantes na literatura especializada. No entanto, a obtenção de um problema geralmente mal posto e o elevado custo computacional, inerente a essas técnicas, limitam ou até mesmo inviabilizam a sua aplicabilidade em estruturas que demandam um modelo de ordem elevada. Para contornar essas dificuldades, na formulação do problema de identificação de danos, pode-se utilizar o Modelo de Superfície de Reposta (MSR) em substituição a um MEF da estrutura. No presente trabalho, a identificação de danos estruturais considera o ajuste de um MSR da estrutura, objetivando-se a minimização de uma função de erro definida a partir das frequências naturais experimentais e das correspondentes frequências previstas pelo MSR. Estuda-se o problema de identificação de danos estruturais em uma viga de Euler-Bernoulli simplesmente apoiada, considerando as frequências naturais na formulação do problema inverso. O comportamento de uma viga de Euler-Bernoulli simplesmente apoiada na presença de danos é analisado, com intuito de se verificar as regiões onde a identificação dos mesmos pode apresentar maior dificuldade. No processo de identificação de danos, do presente trabalho, são avaliados os tipos de superfícies de resposta, após uma escolha apropriada do tipo de superfície de resposta a ser utilizado, determina-se a superfície de resposta considerando os dados experimentais selecionados a partir do projeto ótimo de experimentos. A utilização do método Evolução Diferencial (ED) no problema inverso de identificação de danos é considerado inerente aos resultados numéricos obtidos, a estratégia adotada mostrou-se capaz de localizar e quantificar os danos com elevada acurácia, mostrando a potencialidade do modelo de identificação de danos proposto. / The identification of structural damage is an issue of fundamental importance in engineering, since a structure is subject to deterioration processes and to the occurrence of damage throughout its useful lifetime. The presence of damage compromises the performance and structural integrity, may put human lives at risk and may result in considerable economic losses. Damage identification and structural health monitoring techniques built on Finite Element Model (FEM) updating are constant in the specialized literature. However, the problem generally rank deficient and the high computational cost, inherent to these techniques, limit or even render their applicability in structures that require a high order model. To circumvent these difficulties, in the formulation of the damage identification problem, one may use a Response Surface Model (RSM) in place of a FEM of the structure. In the present work, the identification of structural damage considers the update of a RSM of the structure, with the aim at minimizing an error function defined from the experimental natural frequencies and the corresponding natural frequencies prescribed by a RSM. The problem of structural damage identification in a simply supported Euler-Bernoulli beam is studied, taking into account the natural frequencies in the inverse problem formulation. The behavior of a simply supported Euler-Bernoulli beam, in the presence of damage, is analyzed, in order to verify the identification of regions where the damage identification may present greater difficulties. In the damage identification process, in the present work, after a suitable choice of the type of the response surface model, the surface model is derived considering the experimental data selected from an optimal design of experiments. The use of the Differential Evolution (DE) method in the inverse problem of damage identification is considered. Considering the numerical results obtained, the strategy adopted proved to be able to locate and quantify the damage with high accuracy, showing the capability of the proposed damage identification model.