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- International Conference on Progress in Digital and Physical Manufacturing ProDPM'19 - Book of AbstractsPublication . Almeida, Henrique; Vasco, Joel; Marto, Anabela; Capela, Carlos; Freitas, Dino; Craveiro, Flávio; Bártolo, Helena; Coelho, Luís; Correia, Mário; Vieira, Milena; Ruben, RuiThe “Progress in Digital and Physical Manufacturing” book contains keynotes and papers presented at the first International Conference on Progress in Digital and Physical Manufacturing (ProDPM'19), organized by the School of Technology and Management (ESTG) of the Polytechnic Institute of Leiria (IPLeiria), from the 2nd to the 4th of October 2019. This international conference aims to provide a major international forum for the scientific exchange of multi-disciplinary and inter-organisational aspects performed by academics, researchers and industrial partners in order to exchange ideas in the field of digital and physical manufacturing and related areas. It represents a significant contribution to the current advances in industrial digital and physical manufacturing issues as it contains topical research in this field. The ProDPM'19 conference expects to foster networking and collaboration among participants to advance the knowledge and identify major trends in the field. The conference addresses to industrial challenges focused on current market demands and actual technological trends, such as mass customization, new business and industrial models or predictive engineering. Its contribution in science and technology developments leads to more suitable, effective and efficient products, materials and processes, generating added-value for the Industry and promoting the awareness of the role and importance of the digital and physical manufacturing development in the society. This book is, therefore, an essential reading for all of those working on digital and physical manufacturing, promoting better links between the academia and the industry. The conference papers will cover a wide range of important topics like additive manufacturing, biomanufacturing, advanced and smart manufacturing technologies, rapid tooling, microfabrication, virtual environments, simulation and 3D CAD and data acquisition, materials and collaborative design.
- Characterization and optimization of hybrid carbon–glass epoxy composites under combined loadingPublication . Infante, V; Madeira, JFA; Ruben, Rui B; Moleiro, F; Freitas, Sofia Teixeira deThis work is intended to characterize the mechanical behavior of hybrid carbon–glass composite plates under combined loading of bending and torsion, and to determine the optimal ply fiber orientations to minimize the maximum out-ofplane displacement under such loading conditions. Hybrid composite plates were manufactured with 10 plies each and different stacking sequences using hand lay-up, with carbon fiber and glass fiber reinforcements in an epoxy matrix. Two experimental setups (involving two distinct boundary conditions) are here considered to test the composite plates, both simulating combined loading of bending and torsion. Numerical simulations of the experimental tests were performed in ABAQUS and validated with the experimental data. Using the ply fiber orientations as design variables, the hybrid composite plates were then optimized using global and local optimization using direct search (GLODS). The objective function of minimization of the maximum out-of-plane displacement is carried out through an interactive cycle between GLODS and ABAQUS. Specimens of three optimized laminates were also manufactured for experimental validation. The optimization process contributed to improve the performance of the hybrid composite plates in more than 30% when compared to some non-optimized plates.
- Sebenta de Simulação Computacional - Projeto MecânicoPublication . Ruben, Rui BarreirosNos dias de hoje, o método dos elementos finitos está bastante divulgado e é utilizado, de uma forma generalizada, nas análises de engenharia. Nos próximos anos é expectável um crescimento do número de análises de engenharia realizadas através do método dos elementos finitos. O seu desenvolvimento começou com o advento do computador. A solução da análise por elementos finitos é obtida resolvendo um sistema de equações, como tal só depois do aparecimento do computador é que o processo se tornou eficiente e de aplicação generalizada. Estas duas propriedades, eficiência e aplicabilidade generalizada, são inerentes à teoria utilizada que permite a análise de um grande leque de problemas. O método dos elementos finitos em engenharia foi inicialmente desenvolvido para analisar problemas de mecânica estrutural. No entanto, cedo se reconheceu que o método pode ser aplicado a outro tipo de problemas, como por exemplo, transferência de calor e dinâmica de fluidos. A escolha do modelo matemático que rege o problema físico é sempre a primeira etapa da análise por elementos finitos. A solução aproximada pelo método dos elementos finitos do modelo matemático envolve uma discretização da solução em vários pontos do domínio. O método dos elementos finitos é utilizado para resolver modelos matemáticos complexos, mas é importante apreender que a solução nunca pode conter mais informação que a existente no modelo.
- Manufacturing a Better Future: Scientific Report 2018-2023Publication . Ruben, Rui Miguel Barreiros; Gaspar, Marcelo Rudolfo Calvete; Dias, Juliana Rosa; Ruben, Rui; Calvete Gaspar, Marcelo; Dias, Juliana; Politécnico de LeiriaThe Centre for Rapid and Sustainable Product Development (CDRSP) of the Polytechnic of Leiria (IPL) is a leading research center with the mission of contributing to scientific and technological development through new products, materials and processes that are more sustainable, effective, and efficient. The CDRSP is an organic research unit of the IPL. It was founded in May 2007 to promote economic competitiveness, social cohesion, and sustainable development through new, more efficient, and sustainable products, materials, and processes. Portuguese Additive Manufacturing Initiative (PAMI) was a project that finished in 2021 and CDRSP was the leader. PAMI was a network for fundamental research and development of new techniques for additive manufacturing. The PAMI network was part of the National Roadmap of Research Infrastructures of Strategic Interest to foster an intelligent distribution of the excellent infrastructures that already exist in the central region of Portugal, with different areas of specialty (mechanics, materials, biomedical, and electronics) to increase competitiveness and the capacity to fix the high-performance production sector.
- Automated femoral landmark extraction for optimal prosthesis placement in total hip arthroplastyPublication . Almeida, Diogo F. de; Ruben, Rui; Folgado, João; Fernandes, Paulo R.; Gamelas, João; Verhegghe, Benedict; Beule, Matthieu DeThe automated extraction of anatomical reference landmarks in the femoral volume may improve speed, precision, and accuracy of surgical procedures, such as total hip arthroplasty. These landmarks are often hard to achieve, even via surgical incision. In addition, it provides a presurgical guidance for prosthesis sizing and placement. This study presents an automated workflow for femoral orientation and landmark extraction from a 3D surface mesh. The extraction of parameters such as the femoral neck axis, the femoral middle diaphysis axis, both trochanters and the center of the femoral head will allow the surgeon to establish the correct position of bony cuts to restore leg length and femoral offset. The definition of the medullary canal endosteal wall is used to position the prosthesis' stem. Furthermore, prosthesis alignment and sizing methods were implemented to provide the surgeon with presurgical information about performance of each of the patient‐specific femur‐implant couplings. The workflow considers different commercially available hip stems and has the potential to help the preoperative planning of a total hip arthroplasty in an accurate, repeatable, and reliable way. The positional and orientation errors are significantly reduced, and therefore, the risk of implant failure and subsequent revision surgery are also reduced.
- Fully automatic segmentation of femurs with medullary canal definition in high and in low resolution CT scansPublication . Almeida, Diogo F.; Ruben, Rui; Folgado, João; Fernandes, Paulo R.; Audenaert, Emmanuel; Verhegghe, Benedict; De Beule, MatthieuFemur segmentation can be an important tool in orthopedic surgical planning. However, in order to over- come the need of an experienced user with extensive knowledge on the techniques, segmentation should be fully automatic. In this paper a new fully automatic femur segmentation method for CT images is pre- sented. This method is also able to define automatically the medullary canal and performs well even in low resolution CT scans. Fully automatic femoral segmentation was performed adapting a template mesh of the femoral vol- ume to medical images. In order to achieve this, an adaptation of the active shape model (ASM) tech- nique based on the statistical shape model (SSM) and local appearance model (LAM) of the femur with a novel initialization method was used, to drive the template mesh deformation in order to fit the in-image femoral shape in a time effective approach. With the proposed method a 98% convergence rate was achieved. For high resolution CT images group the average error is less than 1 mm. For the low resolution image group the results are also accurate and the average error is less than 1.5 mm. The proposed segmentation pipeline is accurate, robust and completely user free. The method is ro- bust to patient orientation, image artifacts and poorly defined edges. The results excelled even in CT images with a significant slice thickness, i.e., above 5 mm. Medullary canal segmentation increases the geometric information that can be used in orthopedic surgical planning or in finite element analysis.
- Numerical and experimental evaluation of TPMS Gyroid scaffolds for bone tissue engineeringPublication . Castro, A. P. G.; Ruben, R. B.; Gonçalves, S. B.; Pinheiro, J.; Guedes, J. M.; Fernandes, P. R.The combination of computational methods with 3D printing allows for the control of scaffolds microstructure. Lately, triply periodic minimal surfaces (TPMS) have been used to design porosity-controlled scaffolds for bone tissue engineering (TE). The goal of this work was to assess the mechanical properties of TPMS Gyroid structures with two porosity levels (50 and 70%). The scaffold stiffness function of porosity was determined by the asymptotic homogenisation method and confirmed by mechanical testing. Additionally, microCT analysis confirmed the quality of the printed parts. Thus, the potential of both design and manufacturing processes for bone TE applications is here demonstrated.
- Sebenta de BiofísicaPublication . Macedo, Cidália; Ruben, Rui B.Biomecânica é a mecânica aplicada à biologia. Por outras palavras, é o estudo de fenómenos biológicos através das teorias da mecânica. A palavra “mecânica” foi usada pela primeira vez por Galileu Galilei no livro Discorsi e dimostrazioni, intorno à due scienze attenenti alla mecanica & movimenti local (1638), para descrever força, movimento e resistência dos materiais. Com o decorrer dos anos o seu significado foi estendido, abrangendo o estudo do movimento de todo o tipo de partículas e meios contínuos, incluindo átomos, moléculas, gases, líquidos, sólidos, estrelas e galáxias. De um modo geral, a mecânica é aplicada à análise de qualquer sistema dinâmico. A termodinâmica, a transferência de calor e massa e os métodos computacionais também são disciplinas da mecânica. A biologia, como parte do mundo físico, também é objecto de estudo da mecânica.
- 12º Congresso Nacional de Mecânica Experimental - Livro de ResumosPublication . Capela, Carlos; Correia, Mário Simões; Ruben, Rui
- Numerical-experimental analysis of the permeability-porosity relationship in triply periodic minimal surfaces scaffoldsPublication . Pires, T.; Santos, J.; Ruben, R. B.; Gouveia, B.; Castro, A. P. G.; Fernandes, P. R.Bone Tissue Engineering has been focusing on improving the current methods for bone repair, being the use of scaffolds presented as an upgrade to traditional surgery techniques. Scaffolds are artificially porous matrices, meant to promote cell seeding and proliferation, being these properties influenced by the permeability of the structure. This work employed experimental pressure drop tests and Computational Fluid Dynamics models to assess permeability (and fluid streamlines) within different triply periodic minimal surfaces scaffold geometries (Schwarz D, Gyroid and Schwarz P). The pressure outputs from the computational analysis presented a good correlation with the experimental results, with R2 equal to 0.903; they have also shown that a lower porosity may not mean a lower permeability if the geometry is altered, such as the difference between 60% porous Gyroid scaffolds (8.1*10-9 mm2) and 70% porous Schwarz D scaffolds (7.1*10-9 mm2). Fluid streamlines revealed how the Gyroid geometries are the most appropriate design for most bone tissue engineering applications, due to their consistent fluid permeation, followed by Schwarz D. The Schwarz P geometries have shown flat streamlines and significant variation of the permeability with the porosity (an increase of 10% in their porosity lead to an increase in the permeability from 5.1*10-9 mm2 to 11.7*10-9 mm2), which would imply a poor environment for cell seeding and proliferation.