Developments on Shell and Solid-Shell finite elements technology in nonlinear continuum mechanics

Tese de mestrado. Faculdade de Engenharia. Universidade do Porto. 199

Immersive training weeks in doctoral education

Ph.D. training worldwide, including Doctoral education in Marketing or Engineering fields, has been in trouble for some time. These last turbulent times (pandemic, energy, inflation, and war crises) have only increased the problems previously reported by the 3rd cycle students and early career researchers, including chronic lack of support and poor-quality supervision, with senior researchers rarely trained in mentorship. It is also reported that Ph.D. candidates are inadequately prepared for the cross-disciplinary working and large teams that characterize cutting-edge science today. In the last two decades, opposite decisions took place in Europe concerning the curricula of Doctoral programs. In the 2010s, a large number of classes was added to the Ph.D.s, contributing to almost residual time for thesis research in the first year of the programs. However, ten years later, an abrupt change took place and almost all classes were removed from the Ph.D. curricula, creating a void in (hard and soft skills) training and leaving all the responsibility of training to the supervisor. Ph.D. students reported guidance and isolation issues in the first year. Moreover, today’s little Ph.D. training is fully dedicated to the obtention of their Ph.D. and not to their role in society after the Ph.D. defense. This work discusses a new approach to doctoral education which started first at a professional doctorate implemented at University of Aveiro, Portugal, where few classes take place. This approach considers a novel Ph.D. training, both hard and soft skills development, through special intensive weeks, called Immersive Weeks. In these, distributed during the first year, Ph.D. students exclusively participate in several workshops, acquiring the tools for accomplishing both a successful Ph.D. and a future job. Pilots of this approach took place at the University of Aveiro with large success, while some improvement suggestions have also been pointed out by students.publishe

Development of shear locking-free shell elements using an enhanced assumed strain formulation

The degenerated approach for shell elements of Ahmad and co-workers is revisited in this paper. To avoid transverse shear locking effects in four-node bilinear elements, an alternative formulation based on the enhanced assumed strain (EAS) method of Simo and Rifai is proposed directed towards the transverse shear terms of the strain field. In the first part of the work the analysis of the null transverse shear strain subspace for the degenerated element and also for the selective reduced integration (SRI) and assumed natural strain (ANS) formulations is carried out. Locking effects are then justified by the inability of the null transverse shear strain subspace, implicitly defined by a given finite element, to properly reproduce the required displacement patterns. Illustrating the proposed approach, a remarkably simple single-element test is described where ANS formulation fails to converge to the correct results, being characterized by the same performance as the degenerated shell element. The adequate enhancement of the null transverse shear strain subspace is provided by the EAS method, enforcing Kirchhoff hypothesis for low thickness values and leading to a framework for the development of shear-locking-free shell elements. Numerical linear elastic tests show improved results obtained with the proposed formulation. Copyright (C) 2001 John Wiley Sons, Ltd

O TEMA em questão: investigação

O TEMA tem procurado a excelência através da investigação e inovação de vanguarda desde 1996. Com base no seu capital humano, equipamentos e laboratórios, o TEMA está especialmente alinhado com dois desafios societais, procurando contribuir para uma indústria sustentável e para o bem-estar das pessoas. As Soluções de fabrico sustentável estão focadas no desenvolvimento e na inovação em engenharia e tecnologias de produção, com aplicações industriais subsequentes. Pretende-se aumentar a produtividade, melhorar a qualidade dos produtos e reduzir o desperdício nos processos de produção. A estratégia sobre Tecnologias para o bem-estar visa aumentar a qualidade de vida da sociedade por meio de sistemas de engenharia, focando as pessoas e as suas necessidades. As contribuições reunidas neste livro de atas refletem precisamente o interesse e motivação em fazer a investigação de e para as pessoas. Esta 1ª conferência dedicada a tão importantes temáticas é com certeza um marco na estratégia de continuidade rumo à excelência da investigação promovida pelos Investigadores do TEMA.publishe

Integrated Design in Welding and Incremental Forming: Material Model Calibration for Friction Stir Welded Blanks

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TEMA: livro de serviços

O TEMA tem como missão a excelência científica e tecnológica em vários domínios da Engenharia Mecânica e áreas afins, de acordo com as necessidades da sociedade Portuguesa e do sector industrial e empresarial. As indústrias de manufatura e de processos tecnológicos deparam-se atualmente com desafios de competitividade sem precedentes. O competitivo mercado nacional e internacional exige às empresas que disponibilizem novos produtos (com valor tecnológico acrescentado), e soluções inovadoras e diferenciadores a um ritmo cada vez maior. Ao mesmo tempo, essas empresas devem necessariamente ser flexíveis de maneira a rapidamente se adaptarem às variações das condições de mercado, nomeadamente através da busca de parceiros estratégicos para as suas atividades de investigação e desenvolvimento. (...)TEMA’s mission is to achieve scientific and technological excellence in various fields of Mechanical Engineering and related areas, addressing the needs of Portuguese society and industries. Manufacturing and process technology industries are currently facing unprecedented competitiveness challenges. The competitive national and international market requires companies to offer new products (with added technological value), and innovative and differentiating solutions at an ever-increasing pace. At the same time, these companies must be flexible to rapidly adapt to changing market conditions, by seeking strategic partners for their research and development activities. (...)publishe

Adaptive Remeshing technique with solid-shell elements

peer reviewe

Modelização do comportamento elasto-plástico e dinâmico de estruturas tipo casca

Tese de mestrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 199

Proceedings of the 16th annual ESAFORM Conference on Material Forming: Key Engineering Materials (Volumes 554-557) The Current State-of-the-Art on Material Forming - Chapter 15: Heat Transfer Modelling

International audienc

Single point incremental forming simulation with adaptive remeshing technique using solid-shell elements

Numerical simulation of the single point incremental forming (SPIF) processes can be very demanding and time consuming due to the constantly changing contact conditions between the tool and the sheet surface, as well as the nonlinear material behaviour combined with non-monotonic strain paths. The purpose of this paper is to propose an adaptive remeshing technique implemented in the in-house implicit finite element code LAGAMINE, to reduce the simulation time. This remeshing technique automatically refines only a portion of the sheet mesh in vicinity of the tool, therefore following the tool motion. As a result, refined meshes are avoided and consequently the total CPU time can be drastically reduced