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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The relationship between the MCMI-III and the MMPI-2 in a chronic pain population.

Hardie, John C. 12 1900 (has links)
The purpose of the present study was to study the relationship of MCMI-III clinical scales with MMPI-2 clusters in a chronic pain population. Data was obtained through assessment data (N = 242) from the Dallas Spinal Rehabilitation Center (DSRC), that included MMPI-2 and MCMI-III, as well as pre-and post-assessment information (n = 21) and follow-up questionnaires (n = 19). Subjects' age ranged from 18 to 64. Each patient had a primary diagnosis related to a back and/or a cervical injury, a chronic pain diagnosis, and often medical prescription dependency and/or addition. Each has experienced back pain in the lumbar region (L1 to L5) or cervical region (C1 to C7) for an average of 32 months. Patients with thoracic (mid-spine) and carpal tunnel pain were excluded from this study. A multivariate cluster analysis procedure was performed that yielded 3 homogeneous female MMPI-2 clusters and 4 MMPI-2 homogeneous male clusters. Seven multiple regression analyses were performed to determine which MCMI-III clinical scales predicted cluster membership in the MMPI-2 clusters. Results indicated that MCMI-III clinical scales "7" Compulsive, "X" Validity and "C" Borderline were predictors for membership in the male MMPI-2 clusters. Membership in the female MMPI-2 clusters were predicted by MCMI-III clinical scales "4" Histrionic, "T" Drug Dependence and "2A" Avoidant. Nineteen pre-and post-MCMI-IIIs were analyzed for change after participants completed the six-week pain management program. Paired-sample t-tests were performed on these data and revealed that significant change was noted on 10 MCMI-III clinical scales. Follow-up data questionnaires were available on these same individuals. Results from a correlation analysis indicated that patients who reported having supportive relationships with their spouse and family and a secure source of income report better quality of sleep, better mood, are able to relax and are believe that they are able to manage their pain. Participants who were able to relax and remain calm report better quality of sleep, exercise frequently, report better quality of mood and believe that they will return to work soon. Findings from this study suggest that rather than using the MCMI-III as a diagnostic tool, a more efficient use of this instrument would be to understand maladaptive coping styles that may be present under stressful situations. This study's findings suggest that pain treatment program staff could utilize follow up information, as well as diagnostic information about coping strategies that might appear under stress, to shape interventions. Future research might focus on investigation of factors that predict both improvement and program failure, especially those present at initial intake.
42

Validez de constructo y eficacia diagnóstica de las escalas depresión mayor y trastorno de ansiedad del inventario clínico multiaxial de Millon III (MCMI-III)

Otiniano Campos, Fiorella 21 August 2012 (has links)
La presente investigación tuvo como objetivo determinar la validez de constructo y la eficiencia diagnóstica de las escalas Depresión Mayor y Trastorno de Ansiedad del Inventario Clínico Multiaxial de Millon-III (MCMI-III). Para ello, se aplicó el MCMI-III, el Inventario de Depresión de Beck y el Inventario de Ansiedad de Beck a 100 pacientes ambulatorios de un hospital de salud mental de Lima Metropolitana. La muestra estuvo conformada por 68 mujeres y 32 hombres, cuyas edades fluctúan entre los 18 y 56 años (M=30.53; DE=10.11). Al calcularse la validez de constructo, se encontró que las escalas del MCMI-III presentaban correlaciones convergentes con las otras medidas de depresión y ansiedad utilizadas; sin embargo, también mostraban una pobre habilidad para discriminar la sintomatología del trastorno que dicen medir y la de otra patología considerada en esta investigación. Asimismo, al calcular los criterios que sustentan la efectividad diagnóstica (sensibilidad, especificidad, poder predictivo positivo y poder predictivo negativo) para cada escala, se obtuvo que la escala Trastorno de Ansiedad presenta una mayor eficacia diagnóstica que la escala Depresión Mayor. No obstante, la escala Trastorno de Ansiedad brinda un porcentaje alto de falsos positivos; mientras que la escala Depresión Mayor brinda falsos negativos.
43

El inventario clínico multiaxial de Millon- II (MCMI - II) : validez y confiabilidad en pacientes de dos hospitales de salud mental de Lima Metropolitana

Solís Manrique, Carmen Angélica 11 October 2013 (has links)
El campo de la personalidad es uno de los temas dentro de la psicología que a lo largo de los años no ha recibido consenso entre los investigadores. En la actualidad existen numerosas teorías que intentan aproximarse al constructo, en esta investigación se tomará como punto de partida la estrategia de las disposiciones que asume las características de personalidad de un individuo como más o menos estables a lo largo del tiempo (SánchezLópez y Casullo, 2000) y sirve de base para explicar el surgimiento de la teoría de Theodore Millon, quien da nuevas luces para entender el fenómeno de la personalidad. La personalidad es definida por el autor como un patrón continuo de características psicológicas profundas, que son mayoritariamente inconscientes y difíciles de cambiar y se expresan en casi todas las áreas de funcionamiento del individuo (Millon, 1998 a). Según su modelo, las personas deben pasar por cuatro etapas y cumplir un conjunto paralelo de cuatro tareas para desenvolverse de forma adecuada en la vida. Cada fase evolutiva se recapitula y se expresa ontogenéticamente; en cada etapa se adquieren disposiciones personológicas que representan el equilibrio o la predilección hacia una de las dos tendencias polares del continuum.
44

Caractérisation d'une population de délinquants sexuels évalués en période présententielle avec l'inventaire clinique multiaxial de millon-II (MCMI-II)

Dompierre, Renée-Claude 02 March 2021 (has links)
Ce mémoire a pour objectif l'identification de profils de personnalité distincts au sein d'un échantillon de 105 délinquants sexuels évalués en période présententielle au moyend e l’Inventaire Clinique Multiaxial de Millon-II (MCMI-II). Une analyse de regroupement multivariée de type k-means est appliquée aux échelles de personnalité du MCMI-II. Lesclasses repérées à l'aide de cette procédure confirment l'hétérogénéité de la population et reproduisent les résultats obtenus par une procédure de regroupement de nature plus clinique. Trois profils d'agresseurs se dégagent de l’analyse : le profil contenu, le profil antisocial-colérique et le profil de rapprochement-évitement. Ces classes de sujets se distinguent significativement sur 22 des 26 échelles du test et sur quelques variables externes de type sociodémographique et criminologique. Une présentation de soistratégique incarnée dans une exagération de symptômes est repérable chez le profil antisocial-colérique, alors que le profil contenu démontre surtout de la désirabilité sociale. Le profil de rapprochement-évitement manifeste à la fois les deux modes de présentation stratégique. En somme, cette étude démontre l'utilité potentielle du MCMI-II à la création d'une typologie de délinquants sexuels évalués en période présententielle
45

Behavior of plain and steel fiber reinforced concrete under multiaxial stress

Tawana, Siyd S. January 1995 (has links)
No description available.
46

Multiaxial Fatigue and Deformation Including Non-proportional Hardening and Variable Amplitude Loading Effects

Shamsaei, Nima 03 September 2010 (has links)
No description available.
47

Fatigue optimization of an induction hardened shaft under combined loading

Le Moal, Patrick 01 October 2008 (has links)
An integrated procedure, combining finite element modeling and fatigue analysis methods, is developed and applied to the fatigue optimization of a notched, induction hardened, steel shaft subjected to combined bending and torsional loading. Finite element analysis is used first to develop unit-load factors for generating stress-time histories, and then, employing thermo-elastic techniques, to determine the residual stresses resulting from induction hardening. These stress fields are combined using elastic superposition, and incorporated in a fatigue analysis procedure to predict failure location and lifetime. Through systematic variation of geometry, processing, and loading parameters, performance surfaces are generated from which optimum case depths for maximizing shaft fatigue performance are determined. General implications of such procedures to the product development process are discussed. / Master of Science
48

Couplages thermomécaniques dans les alliages à mémoire de forme : mesure de champs cinématique et thermique et modélisation multiéchelle / Thermomechanical coupling in shape memory alloys : thermal and kinematic full field measurements and multi-scale modeling

Maynadier, Anne 30 November 2012 (has links)
L’utilisation croissante des Alliages à Mémoire de Forme (AMF) dans des structures de plus en plus complexes, notamment en vue d'applications médicales, rend nécessaire la compréhension des phénomènes régissant leur comportement et plus précisément la pseudo-élasticité. Le fort couplage thermomécanique, résultant de la transformation de phase martensitique, est un point clé de ce comportement. Les travaux de thèse présentés sont consacrés à l’étude et la modélisation de ce couplage. Tout d’abord, la transformation de phase martensitique provoque une déformation et une émission de chaleur couplées qui peuvent se localiser en bandes de transformation sous sollicitation uniaxiale. Une partie de cette thèse a été consacrée au développement de la Corrélation d’Images InfraRouge, qui permet à partir d’un unique film IR de mesurer conjointement, en une seule analyse, les champs cinématiques et thermiques discrétisés sur un même maillage éléments finis. Une application à l’analyse d’un essai de traction sur AMF de type NiTi a été réalisée. Le comportement pseudo-élastique a aussi été abordé d’un point de vue modélisation. Une large part de ce travail de thèse a donc été consacrée à l’élaboration d’un modèle multiéchelle et multiaxial, décrivant le comportement d’un VER à partir de la physique de la transformation martensitique à l’échelle de la maille cristalline. L’approche est inspirée de modèles multiéchelles développés pour la modélisation d’autres couplages multiphysiques et notamment magnéto-élastique. La troisième partie de cette thèse a été consacrée à l’élaboration d’un modèle de structure 1D sous traction uniaxiale. Dans un premier temps un modèle de thermique 1D ainsi qu’un modèle mécanique phénoménologique à seuils ont été développés. Les simulations rendent compte des phénomènes de transformation diffuse accompagnant l’élasticité puis de la transformation localisée. L’algorithme est notamment capable de gérer les deux sens de transformation. Ce modèle met en compétition les deux phénomènes transitoires de génération et évacuation de la chaleur par la transformation de phase et les échanges thermiques avec l’environnement. Ainsi, il est capable de reproduire la relation liant le nombre de bandes de transformation générées à la vitesse de sollicitation et aux conditions aux limites thermiques. Un travail été initié pour coupler ce modèle de structure et de gestion de la thermique au modèle monocristallin multiaxial. Sans encore reproduire la localisation de la transformation en bande, les simulations de traction montrent un hystérésis, issu des pertes thermiques dans l’air ambiant, bien que le modèle de comportement multiéchelle élémentaire soit écrit dans un cadre réversible, l’irréversibilité et la localisation étant avant tout des effets de transferts. Le couplage thermomécanique à la source des comportements si spécifiques des AMF que sont la super élasticité et la mémoire de forme ont donc été étudiés sous divers points de vue : expérimentalement, par l’établissement de modèles de comportement, par la simulation de structures 1D et des échanges thermiques mis en jeu. Les outils et modèles ont été appliqués à l’étude du Ni49,75at%Ti, support de ce travail, mais sont facilement adaptables à tout autre AMF. L’approche utilisée pour la modélisation multi-échelle peut être étendue à d’autres couplages, par exemple en cumulant les couplages thermo- et magnéto- mécaniques en vu de l’étude des Alliages à Mémoire de Forme Magnétiques par exemple. / The increasing use of Shape Memory Alloys (SMA) for complex structure, especially for medical applications, requires a better understanding of the phenomena governing their behaviors and particularly the super-elasticity. The strong thermomechanical coupling resulting from the martensitic phase transformation is a key point of this behavior. The thesis is devoted to the study and modeling of this coupling. First, the martensitic phase transformation causes coupled local deformation and heat emission that can locate onto transformation bands when structure undergoes uniaxial stress. A part of this thesis has been devoted to the development of InfraRed Image Correlation (IRIC). This technique permits us to measure by a single analysis, from a single IR film, both kinematic and thermal fields discretized on the same finite element mesh. An application to the analysis of a tensile test on a NiTi type AMF has been made. Superelastic behavior is also discussed from a modeling point of view. A large part of this work has been devoted to the development of multiaxial multiscale model describing the behavior of a RVE from the description of martensitic transformation at the crystal scale. The approach is inspired from multiscale models developed for modeling other multiphysic couplings especially the magneto-elastic coupling. It is based on the comparison of the free energies of each component, without any topological description. A probabilistic comparison is made, using a Boltzmann distribution, to determine the internal variables : the volume fractions. Interfaces are not taken into account. This model allows the simulation of the effect of any thermo-mechanical loading. It well gives account of the superelasticity, including the asymmetry in tension / compression ... The third part of this thesis has been devoted to the development of a one dimensional model for structure under uniaxial tension. In a first step, a 1D thermal model and a phenomenological mechanical model, based on the Clausius Clapeyron diagram have been developed. The simulations account for the diffuse transformation accompanying the elasticity at the very beginning of stress-strain behavior, and localized phase transformation afterthat. The algorithm is capable of handling two-way transformation. This model emphasizes competition both transient phenomena : generation and heat dissipation by the phase transformation and heat exchange with environment. Thus, it is able to reproduce relationship linking the number of nucleated transformation bands to the strain rate and the thermal boundary conditions. A study has been initiated to couple this model to the singlecrystalline multiaxial RVE model detailed in the previous part. It is currently not able to model the localization phenomenon, but the simulations show a tensile hysteresis issued from the thermal losses in the air. Indeed, even if the local multiscale model is written in a reversible way, irreversibility and the localization are primarily structural effects. The thermomechanical coupling is at the origin of the so specific AMF behavior (super elasticity and shape memory effect), it has been studied from various points of view: experimentally, by establishing RVE models, by simulating 1D structures and heat exchange. Developed tools and models have been applied to the study of Ni49, 75at% Ti, but are easily adaptable to other AMF. The approach used for the multi-scale modeling can be extended to other couplings, such as couplings cumulating the thermo-and magneto-mechanical aspect for the study of Magnetic Shape Memory Alloys for example.
49

Metodologia moderna para análise de fadiga baseada em elementos finitos de componentes sujeitos a fadiga uni e multiaxial. / Modern methodology for FE-Based Fatigue analysis of components under uni- and multiaxial fatigue.

Takahashi, Bruno Ximenes 04 July 2014 (has links)
Grande parte dos componentes mecânicos e estruturas são solicitados por carregamentos que variam com o tempo e frequentemente falham por fadiga. Neste sentido, é indubitável que o modo de falha por fadiga seja considerado no projeto mecânico de componentes, equipamentos e estruturas sujeitas a carregamentos cíclicos. Os livros de projetos de máquinas ainda são os mais utilizados na indústria como referência teórica e prática ao dimensionamento contra a fadiga de produtos. Entretanto, muitos deles ainda não incluem as últimas descobertas e metodologias mais modernas para o cálculo de durabilidade de estruturas. Adicionalmente, de uma maneira geral, grande parte dos livros especializados em fadiga também não trazem informações detalhadas sobre a previsão de vida em fadiga sob a ótica do projeto mecânico, como a análise utilizando critérios de Fadiga Multiaxial e a análise de fadiga baseada em Elementos Finitos (FE-Based Fatigue Analysis). Baseado neste cenário, este trabalho tem o objetivo de propor um procedimento para avaliar a vida em fadiga de componentes e estruturas reunindo os métodos mais recentes utilizados nesta área. Dentre os vários assuntos incluídos no procedimento proposto, destacam-se: as importantes contribuições propostas pelo Conselho Alemão de Pesquisa em Engenharia (FKM-Guideline); a utilização de Análise por Elementos Finitos (FEA) na previsão de vida em fadiga; o cálculo do fator de tensão média utilizando pseudo tensões provenientes de FEA; a contabilização do efeito de entalhe em componentes com geometria complexa utilizando o Método do Gradiente de Tensão Relativo em conjunto com FEA, que pode ser aplicado tanto em carregamento uniaxial quanto em carregamento multiaxial; a contabilização do dano por fadiga em carregamento multiaxial de amplitude variável; a densidade da malha de elementos finitos adequada para utilizar em fadiga computacional; e a aplicação da teoria e dos critérios de Fadiga Multiaxial, principalmente em FE-Based Fatigue Analyses, cuja utilização é imprescindível em estruturas sujeitas a tensões cíclicas em mais de uma direção (x,y,z). / Most of mechanical components and structures are subjected to time varying loading and therefore often present fatigue failure. Therefore, it is essential to consider the fatigue failure mode in the project of components, machines and structures under cyclic loading. Design of Machine Elements books are still the most used in industry as theoretical and practical reference for designing products against fatigue. However, many of them still do not include the latest findings and methodologies used in fatigue life assessment of structures. Additionally, overall, most of the specialized fatigue books also do not include detailed information about fatigue life assessment in a mechanical project view, as the fatigue analysis using Multiaxial Fatigue criteria and the fatigue life prediction using the Finite Element Method (FE-Based Fatigue Analysis). Based on this fact, this thesis proposes a procedure for predicting component and structures fatigue life, gathering together the most recent methods used in the fatigue area. Among the several subjects included in this procedure, we can highlight: the important contributions of the German Engineering Research Council (FKM-Guideline); the use of Finite Element Analysis (FEA) in the fatigue life assessment; the calculation of the mean stress factor using the pseudo stresses from FEA; the computation of the notch eect in geometrically complex components using the Relative Stress Gradient Method in conjunction with FEA, method which can be applied both in uniaxial loading and multiaxial loading; the estimation of the fatigue damage in structures under variable amplitude multiaxial fatigue loading; the selection of an adequate Finite Element mesh density to use in computational fatigue; and the aplication of the Multiaxial Fatigue theory and criteria, specially in FE-Based Fatigue Analyses, of which use is essential in structures under ciclic stresses in 2 or 3 directions (x,y,z).
50

Metodologia de análise de fadiga para o desenvolvimento de componentes via CAE e medições estruturais / Fatigue analysis methodology for components development via CAE and structural measurements

Scozzafave, Caio de Carvalho 06 October 2014 (has links)
Esse trabalho propõe uma metodologia de otimização no processo de aprovação de componentes estruturais submetidos a carregamentos cíclicos que já tiveram a primeira rodada de testes físicos e falharam sem atingir os critérios de aprovação previamente estabelecidos. Os estudos de caso utilizados na aplicação do método foram dois componentes de suspensão de veículos comerciais. A metodologia proposta tem em sua base diversos tópicos da engenharia, como o estudo dos materiais dos componentes, análise de tensão e fadiga via elementos finitos, medição e análise de sinal de deformação e força, teste de durabilidade acelerado, além de correlação entre simulação e realidade. No âmbito da fadiga, a análise foi efetuada em ambiente virtual, através de um programa capaz de importar as tensões da simulação numérica e medições estruturais. É utilizada a metodologia S-N (tensão vida), através da criação de curvas S-N locais sintéticas, alteradas da curva original via fatores de influência como gradiente de tensão, tensão média (via diagrama de Haigh), rugosidade superficial e também pela distribuição estatística das propriedades do material. Por se tratar de carregamentos cíclicos aleatórios, uma análise de proporcionalidade do sinal é feita, além da utilização da previsão de vida em fadiga abordando os conceitos da fadiga uniaxial (utilizando tensão principal e von Mises) e também no caso multiaxial (utilizando o método dos planos críticos e tensão normal escalonada). Um grande grau de correlação entre simulação de tensão e testes físicos foi encontrado (pelo menos 90%). A previsão de falha por fadiga para os dois casos teve seus melhores resultados utilizando o método dos planos críticos. Os dois componentes encontram-se homologados por essa metodologia e atualmente são utilizados por veículos comerciais de série sem falhas observadas em campo, mostrando uma tendência de assertividade do método. / This work proposes a methodology to optimize the approval of structural components subjected to cyclic loadings that have had the first round of physical testing and failed to achieve the approval criteria previously established process. The case studies used in the application of the method were two commercial vehicle suspension components. The proposed methodology has its base in various engineering topics such as the study of the component materials, stress analysis and fatigue via finite elements, measurement and signal analysis of deformation and strength, accelerated durability test, and correlation between simulation and reality. Within the fatigue, the analysis was performed in a virtual environment, through a software able to import the stresses of numerical simulation and structural measurements. The S-N method (stress life) is used, through the creation of local synthetic S-N curves. The curve is modified from the original via influence factors such as gradient stress, mean stress (via Haigh diagram), surface roughness and also the statistical distribution of material properties. Because of the random cyclic loading, an analysis of the proportionality sign is made, in addition of the use of the fatigue life prediction by uniaxial fatigue (using principal stress and von Mises) and also in the multiaxial case (using the critical plans method and normal scaled stress). A high degree of correlation between stress and physical simulation tests was found (at least 90%). The prediction of fatigue failure for the two cases had their best results using the critical plans method. The two components are approved by this methodology and are currently used by commercial vehicles series without failures observed in the field, showing an assertiveness trend of the method.

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