Fábio Gonçalves Teixeira

Experimental Analysis of the Influence of Hydrostatic Stress on the Behaviour of an Adhesive Using a Pressure Vessel

The modelling of the non-linear behaviour of ductile adhesives requires a large experimental database in order to represent accurately the strains which are strongly dependent on the tensile-shear loading combination. Various pressure-dependent constitutive models can be found in the literature, but only a few experimental results are available, for instance, to represent accurately the initial yield surface taking into account the two stress invariants, hydrostatic stress, and von Mises equivalent stress. This paper presents the possibility of combining the use of tests on bulk specimens and tests on bonded assemblies, which strongly limit the influence of the edge effects, with a pressure vessel especially designed to study the influence of hydrostatic stress. The latter allows pressures up to 100 MPa to be applied during mechanical testing. For a given strain rate of the adhesive, experimental results using various stress paths are presented in order to analyse the influence of the hydrostatic stress on the mechanical behaviour of an adhesive. The analysis of the results focuses herein on the modelling of the initial yield surface, but such results are also useful for the development of the flow rules in the case of 3D pressure-dependent models.

Study of Influence of Substrate Topography on Stress Distribution in Structural Adhesive Joints

This paper analyses the influence of surface roughness on adhesive bond strength. Numerical simulations were performed to evaluate the influence of geometry on the performance of structural adhesive joints. The objective is to create a model to describe the behaviour of the interphase of adhesive joints according to its geometry. Two-dimensional simulations with theoretical geometries were performed considering parameters of roughness, stress distribution, and contact area to verify the qualitative influence of substrate topography on the adhesion of a joint. Numerical analyses were done to verify the effect of the interpenetration of materials on the mechanical properties of the interphase.

Inspædia: [Almost] Everything About Simplicity, Playfulness and Inspiration

The aim of this paper is to disclose the new research developments and the results from the systematization of experience and user interaction with the Inspaedia (a new web knowledge “Agora”), to inspire a dynamic, collaborative, and interactive intelligence among the inspaediers. We will explain in detail and describe the design process and discuss the ultimate design interaction concept and development regarding (almost everything about) simplicity and playfulness of the inspaediers’ experience to transform relevant information (related > meanfull > useful) in productive knowledge (inspiration > insight > foresight) in a very easy and quick way (usability: learnability; understandability; operability; attractiveness…), with a smile in the face (satisfaction) and a wow in the mind (or in the soul).

A color model in the usability of computer interface applied to users with low vision

This paper presents the results of a research on the usability of computer interfaces through colors for Low Vision users. It describes the methodology used, the 3 web interfaces tested for usability with the users in question, showing the results for the development of a prototype interface with colors as the main aspect. The prototype developed is presented with the usability test carried out with it. As a result of the work, a proposed color model is presented that includes Low Vision users in the construction and upgrading of computer interfaces, aimed at the usability of web interfaces.

Web-Based Learning Design Tool.

Purpose – The purpose of this paper is to propose a web‐based tool that enables the development and provision of learning designs and its reuse and re‐contextualization as generative learning objects, aimed at developing educational materials.Design/methodology/approach – The use of learning objects can facilitate the process of production and delivering of educational material and their reuse and re‐contextualization in different scenarios – such process is due to the current development stage of information and communication technologies (ICTs), which allow easy access to products and services related to them. ICTs combined with instructional design theories, lead to the emergence of new generations of distance learning, which add educational content to web‐based services. From this combination rises a hybrid mode of education, which combines tools for face‐to‐face and distance learning (blended learning).Findings – The use of the web as a platform for production and management of learning objects comes...

Design-Based Learning Supported by Empirical-Concrete Learning Objects in Descriptive Geometry

Undergraduate programs in Engineering, Architecture, and Design offer courses on Descriptive Geometry and Technical Drawing at early stages, to provide students with basic knowledge to deal with subjects related to representation throughout their careers. However, first and second-year students face some problems, as they have small (or none) experience with orthographic views and need to learn this form of communication at the same time they are learning it. A way to diminish the level of abstraction of those courses is to engage the students in meaningful activities and hands-on experiences, providing them with empirical-concrete resources, so they can manipulate and analyse tangible objects, instead of devising abstract elements. This paper proposes a way to ease the transition from 3D objects to 2D views, leveraging the spatial abilities and reasoning of the students, using constructive blocks through a design-based learning approach. The blocks are provided at the beginning of the course and serve as support for the classroom activities.

A Multiview Interactive Interface for the Solution of Descriptive Geometry Problems

Descriptive Geometry (DG) is the knowledge base for the design process (Engineering, Architecture, and Design). Despite its importance, in many universities, its teaching has been neglected and often has disappeared as a discipline, and its content has been integrated into more comprehensive courses such as technical drawing and CAD. We believe that the DG teaching-learning process should be improved so that the disciplines of technical drawing and computational drawing tools can be better used in the education of designers. For this reason, we developed the HyperCAL3D, an application that performs all DG processes in multiple projections in a virtual environment. Although it is a software to aiding learning DG, its use depends on the knowledge of DG, because there are no automatic solution tools, the user must know the DG solution processes. Thus, this desktop application has allowed teachers and students to use DG knowledge to solve design problems quickly, directly in a virtual environment. This implementation is a milestone for the teaching of DG, as it allows the solution of complex problems in a few seconds, with high precision and with the understanding of the process being carried out. Such approach is a significant improvement because without the aid of the software the student must use the manual drawing as the only alternative, which is slow and laborious, and hinders the learning process.

AVALIAÇÃO DE MODELOS OBTIDOS POR DIFERENTES SISTEMAS DE DIGITALIZAÇÃO 3D PARA PRODUTOS PERSONALIZADOS

O objetivo e avaliar modelos obtidos por diferentes sistemas de digitalizacao tridimensional e verificar se as variacoes geometricas podem gerar implicacoes nas medidas antropometricas para o projeto de produtos personalizados. Para as comparacoes e analises, a perna direita de um sujeito foi digitalizada, pelo scanner 3D de luz branca (Artec Eva) e pelo scanner por infravermelho (kinect da Microsoft). Os modelos 3D obtidos foram comparados atraves do software Geomagic Q ualify . Tambem, atraves da usinagem CNC foram realizadas comparacoes de analises visuais, por mapeamento de pressao e por termografia. Os resultados obtidos foram satisfatorios tanto para o uso do scanner Kinect quanto para o Artec Eva. Porem, houve uma diferenca dimensional de aproximadamente 7 mm entre os modelos 3D, o que demonstra uma maior precisao de medidas nos modelos obtidos pelo scanner Artec Eva. No entanto, nao invalida o uso do Kinect para o desenvolvimento de projetos de produto personalizados. O que ira determinar qual o scanner 3D mais adequado para cada tipo de produto e a necessidade do grau de precisao para que o produto desempenhe sua funcao com maior conforto e eficiencia.