Engineering, Automotive Engineering, Materials Science, Polymers and Plastics
23
Scopus Publications
Scopus Publications
Simulation studies of printed circuit board using finite element method to evaluate the potential of cellulose fibres to replace glass fibres J. C. Velosa, J. M. R. Curto Materialwissenschaft Und Werkstofftechnik, 2025 The replacement of glass fibres by cellulose‐based fibres in printed circuit board (PCB) is motivated by environmental reasons since the use of biodegradable components from renewable sources will have a significative impact in the life‐cycle assessment and sustainability evaluation of these materials. To study the potential of replacement of glass fibres by natural fibres in printed circuit board manufacturing we have used a finite element method (FEM) computational simulation methodology to evaluate the influence of key structural parameters on their thermomechanical properties, with the goal of predicting and quantifying its warpage at soldering process temperatures. In our work some printed circuit board (PCB) configurations have been selected and modelled using different natural fibres and compared with conventional printed circuit board systems, designated by flame retardant epoxy (FR4), that are made from glass fibres, epoxide resin and copper foils. The simulation results indicate that the printed circuit board assembly process, namely the number of layers, has a major influence on the key thermomechanical properties that were studied. Some optimized printed circuit board configurations were selected, based on the simulation studies, and the natural fibres were classified according to their potential to be used in the development of sustainable printed circuit board materials.
Simulation Studies to Compare Innovative Cellulose-Based Fibers Composites Printed Circuit Border with Glass Fibres João C. Velosa, Abílio P. Silva, Geoffrey R. Mitchell, Joana M.R. Curto Key Engineering Materials, 2025 Electronic equipment is exposed to rough vibrations throughout its life cycle. Electronic components can be damaged by these vibrations and could lead to device failure. The conventional Printed Circuit Boards (PCBs) that form the foundation of numerous electronic devices are predominantly constructed from copper films that are bound to fiber epoxy laminates, such as FR4, which is composed of glass fibers, and FR1, which is composed of paper. Being biodegradable makes cellulose a more sustainable choice. Nonetheless, it is imperative to uphold performance criteria, and this work aims to contribute to this assessment. Using simulation studies, we compare the behavior of these two PCBs under vibrational stress. The finite element analysis (FEA) of the vibrations for the PCB samples was modelled using the Ansys software. The FEA simulations show that both types of PCBs have similar movements and accelerations at certain places on the board.
2D SIMULATION OF THE PLACEMENT OF A PIN-THROUGH-HOLE COMPONENT AND SOLDER PASTE MELTING Nelson Rodrigues, Inês Teixeira, Violeta Carvalho, Duarte Santos, Joao Velosa, et al. ASME International Mechanical Engineering Congress and Exposition Proceedings Imece, 2022 In the present work, a numerical model was developed to simulate the placement of a pin through-hole (PTH) component in an aperture containing solder paste by using Ansys Fluent® software. The work uses numerical tools to understand the physical process and the solder paste behaviour for future manufacturing improvements. The component movement was simulated with the dynamic mesh model through a user-defined function (UDF). Due to software limitations, the pin of the component is already contacting the solder paste at the start of the movement. additionally, the contact detection feature was activated to prevent the pin and PCB contact during the solder paste melting. Nevertheless, the component can still move in the domain if other forces act upon it, except in the direction where the contact would occur. The second point to address is the meniscus formation process. This begins with the evaporation of the solder paste flux, causing a volume reduction followed by the melting of the metallic beads. The simulation allowed us to see that the melted solder surrounded the pin through capillarity and reproduced the phenomena of this solder printing process. This work allowed to follow the behaviour of both the component and the solder paste.
NUMERICAL SIMULATION OF SOLDER PASTE PRINTING ON THROUGH-HOLE COMPONENTS Duarte Mateus, Senhorinha Teixeira, Nelson Rodrigues, Violeta Carvalho, Duarte Santos, et al. ASME International Mechanical Engineering Congress and Exposition Proceedings Imece, 2021 The increased demand for smaller and more reliable electronic devices, pressures companies to tune and innovate the production methodologies, always aiming to decrease the production time while maintaining the products’ quality. In the manufacturing of a Printed Circuit Board - PCB, there are two main types of electronic components, namely, Surface-Mount-Devices and Through-Hole components. Both connections are achieved through soldering, an essential manufacturing process that greatly affects the quality of the final product, and may compromise the lifetime of the PCB. While SMD components are commonly soldered by a reflow process, TH components are generally soldered by a wave soldering process. However, a PCB is generally composed of both types of components. Since both processes are too different in nature, the manufacturing of the board requires two separated mounting lines which represent increased costs and production time. Taking this into account, the present study investigates the usage of the reflow solder printing to deposit the solder paste on through-hole apertures both experimentally and numerically. In general, the results were similar showing a tendency for the solder paste to deposit on the aperture’s right side. Nevertheless, the numerical model predicts a filling area greater (by 22%) than that verified experimentally.
Application of taguchi method in optimizing fabrication of composite panels for interior dividing walls J. Velosa, S. Rana, T. Santos, R. Fangueiro, L. Ramos Polymers and Polymer Composites, 2013 In order to save material and energy, an increased growth can be noticed in recent times in the use of low-cost and light-weight solutions for the interior dividing walls of buildings. In this context, the main aim of the present research work was to develop light-weight composite panels based on non-woven fabrics for this application as an alternative to more commonly used materials and to optimize the manufacturing process parameters in order to maximize their mechanical performance. Thermo-bonded nonwoven geo-textiles made from polyester (70%) and polypropylene (30%) fibres were consolidated using compression moulding technique, varying the various structural and process parameters, such as number of layers, compression time, temperature and pressure. Taguchi method was used to design the experiments, as well as to understand the influence of various parameters on tensile and flexural strengths of developed composite panels and to optimize them in order to maximize these properties. According to the analysis, a consolidation temperature of 210°C, pressure of 30 bars, compression time of 35 minutes and 30 layers are required to achieve the maximum values of tensile and flexural strength with minimum variability.
Waste fiber reinforced composite materials: Production and mechanical properties João Velosa, Raul Fangueiro, Nelson Martins, M. Fernandes, Filipe Soutinho Materials Science Forum, 2013 Today, the cost, excellence and availability of raw materials are of principal importance. Due to environmental concerns, a very large number of companies are currently developing manufacturing processes using alternative materials for their crop and in search of new markets for the sub-products of their first-line production. Textile industry is an example of the reality that the industry is living these days. With a significant production of waste fibrous materials, textile companies are now looking for applications where waste materials could be an added-value material. Composites reinforced by fibres are being considered for several uses when high performance is essential. The corrosion resistance, potentially high overall durability, light weight, tailor ability and high specific performance attributes enable the use of composite materials in areas in which the use of conventional material might be constrain due to durability, weight or lack of design flexibility. This paper describes the work that is being done at University of Minho concerning the development of waste fibers reinforced composite materials. Different waste fibers reinforced composite materials have been produced varying the density and the variation in ratio of resin and waste fibers. Waste fibers have been collected within some textile companies and processed in order to individualize the fibers and to allow subsequent processing. Composite panels have been produced by compression moulding technique, through the application of heat and pressure. Panel thicknesses of 5 mm using resin aminoplastic for urea-formaldehyde have been produced. Materials thus obtained have been tested in tensile, bending, compression test. The results obtained are presented and discussed.
Predicting mechanical behavior of novel sandwich composite panels based on 3D warp-knitted spacer fabrics using Finite Element Method (FEM) Eccm 2012 Composites at Venice Proceedings of the 15th European Conference on Composite Materials, 2012
Mechanical properties of composite materials reinforced by an innovative multiaxial woven fabric Proceedings of the 10th International Conference on Textile Composites Texcomp 10 Recent Advances in Textile Composites, 2010
Advances in vacuum infusion processing using spacer fabrics as engineered reinforcement Proceedings of the 10th International Conference on Textile Composites Texcomp 10 Recent Advances in Textile Composites, 2010
Production of thermoplastic towpregs J.C. Velosa, João Pedro Nunes, João F. Silva, Carlos A. Bernardo, António Torres Marques Materials Science Forum, 2010
