The objective of this research is to assess the performance of interface elements in the finite element method. Interface elements are implemented in the finite element codes such as MSC.NASTRAN, which is used in this study. Interface elements in MSC.NASTRAN provide a tool to transition between a shell-meshed region to another shell-meshed region as well as from a shell-meshed region to a solid-meshed region. Often, in practice shell elements are layered on shell elements or on solid elements without the use of interface elements. This is potentially inaccurate arising in mismatched degrees of freedom. In the case of a shell-to-shell interface, we consider the case in which the two regions have mismatched nodes along the boundary. Interface elements are used to connect these mismatched nodes. The interface elements are especially useful in global/local analysis, where a region with a dense mesh interfaces to a region with a less dense mesh. Interface elements are used to help avoid using special transition elements between two meshed regions. This is desirable since the transition elements can be severely distorted and cause poor results. Accurate results are obtained in shell-shell and shell-solid combinations. The most interesting result is that not using interface elements can lead to severe inaccuracies. This difficulty is illustrated by computing the stress concentration of a sharp elliptical hole.

Šiame darbe nagrinėjamos vieno vektorinės grafikos formato – SVG – taikymo galimybės kuriant žiniatinklio aplikacijas, svetaines. Darbe pateikti keturi SVG taikymo variantai – „SVG panaudojimas su JavaScript ir CSS“, „SVG paslėpimas po JavaScript objektais“, „SVG paslėpimas po XBL elementais“, „SVG ir elementai symbol/use“. Kiekvienu atveju nurodoma, kaip galima realizuoti naudotojo sąsajos elementus, išvardinti metodo privalumai, trūkumai. Taip pat visais keturiais metodais realizuotas veikiantis pavyzdys – vektorinės grafikos redaktorius, kuris parodo, kad jau šiandien SVG galima taikyti savo projektuose. Darbe aprašomi bendri SVG integravimo į žiniatinklio turinį principai, trumpai palyginama SVG ir Flash technologija, susipažinama su minėtais realizavimo variantais, naudotojo sąsajos elementais, pagal tam tikrus kriterijus pateikiamos rekomendacijos, kada koks SVG taikymo variantas yra parankesnis. / This work covers applications of one of the vector graphics format – SVG in internet applications, sites. The work presents four SVG usage variants – “SVG with JavaScript and CSS”, “SVG behind JavaScript objects”, “SVG behind XBL elements”, “SVG and symbol/use elements”. In every case examples of implementing user interface elements are given. Also advantages and disadvantages are listed for mentioned methods. As an example vector graphics redactor was implemented in four different ways, which shows that SVG can be used for today’s applications. The work describes common SVG integration principles in the web, briefly compares SVG and Flash, introduces four SVG usage variants, user graphics interface elements, gives recommendations which method is better according to chosen criteria.

[pt] Este trabalho consiste no desenvolvimento de um modelo numérico para simular o fraturamento em estruturas de concreto. Como ferramentas principais são utilizados o Método dos Elementos Finitos (MEF) e alguns conceitos da Mecânica da fratura aplicada ao concreto. A principal palavra-chave que caracteriza este trabalho é o -elemento de interface-. Este elemento finito permite modelar descontinuidades na malha de elementos finitos entre as arestas dos elementos. Neste trabalho, estes elementos são utilizados para representar fissuras em estruturas de concreto. A modelagem destas fissuras é suportada por um conceito de fissura discreta, o qual está acoplado a um modelo constitutivo elástico com amolecimento, específico para a fissura ou para o elemento de interface.Neste trabalho, as análises não-lineares abrangeram sistemas estruturais com modo de fraturamento I. / [en] This work consists in the development of a numerical model in order to simulate the fracture process in concrete structures. This model is supported by concepts of the Finite Element Method and the Fracture Mechanics applied to concrete. The main keyword which characterizes this work is interface element. This finite element permits the modelling of discontinuities in the finite element mesh among the edges of the elements. In this work, these elements are used to represent cracks in concrete structures. The cracks modelling is supported by the discrete crack concept, which is associated to a constitutive model called elastic-softening, specific for the crack or for the interface element. In this work, the nonlinear analyses were limited to structural systems under fracture mode I.This work consists in the development of a numerical model in order to simulate the fracture process in concrete structures. This model is supported by concepts of the Finite Element Method and the Fracture Mechanics applied to concrete. The main keyword which characterizes this work is interface element. This finite element permits the modelling of discontinuities in the finite element mesh among the edges of the elements. In this work, these elements are used to represent cracks in concrete structures. The cracks modelling is supported by the discrete crack concept, which is associated to a constitutive model called elastic-softening, specific for the crack or for the interface element. In this work, the nonlinear analyses were limited to structural systems under fracture mode I.This work consists in the development of a numerical model in order to simulate the fracture process in concrete structures. This model is supported by concepts of the Finite Element Method and the Fracture Mechanics applied to concrete. The main keyword which characterizes this work is interface element. This finite element permits the modelling of discontinuities in the finite element mesh among the edges of the elements. In this work, these elements are used to represent cracks in concrete structures. The cracks modelling is supported by the discrete crack concept, which is associated to a constitutive model called elastic-softening, specific for the crack or for the interface element. In this work, the nonlinear analyses were limited to structural systems under fracture mode I. / [es] Este trabajo consiste en el desarrollo de un modelo numérico para simular fracturas en extructuras de concreto. Se utilizan como herramientas principales el Método de los elementos Finitos (MEF) y algunos conceptos de la Mecánica de la fractura aplicada al concreto. La principal palabra clave que caracteriza este trabajo es el -elemento de interfaz-. Este elemento finito permite modelar discontinuidades en la malla de elementos finitos entre las aristas de los elementos. En este trabajo, los elementos son utilizados para representar fisuras en extructuras de concreto. El modelo de estas fisuras se soporta por un concepto de fisura discreta, que está acoplado a un modelo constitutivo elástico, específico para la fisura o para el elemento de interfaz. En este trabajo, los análisis no lineales consideran sistemas extructurales con modo de fractura I.

During an extravehicular activity (EVA), the role of an astronaut involves a multitude of complex tasks. Whether that task is a science experiment aboard the International Space Station, or traversing extraterrestrial terrain – attention, communication, and instruction are essential. As an aid, augmented reality (AR) can portray suit informatics and procedures within line-of-sight while minimizing attentional loss. Currently, there exists little research highlighting the human systems considerations to qualify AR systems for space suit applications. This study quantifies user interface (UI) and human performance measures for an AR prototype on the Mark III space suit. For user testing, 21 military pilots and personnel (11 men, 10 women) evaluated UI search tasks and completed a series of AR-instructed EVA dexterity tasks in an elevated luminosity, background clutter, and workload scenario. UI results suggest correlations for readability and usability; whereas, human performance results provide situational awareness, workload, and task performance data.