Mechanical, Fatigue, and Thermal Characterization of ASA, Nylon 12, PC, and PC-ABS Manufactured by Fused Filament Fabrication (FFF) Ângela Rodrigues, Ricardo Branco, Margarida Franco, Rui Silva, Cândida Malça, et al. Polymers, 2026 Additive manufacturing has been widely adopted in industry as an alternative to traditional manufacturing processes for complex component production. In fact, a diverse range of materials, particularly polymers, can be processed using 3D printing for biomechanical applications (e.g., prosthetics). However, in-depth evaluation of these materials is necessary to determine their suitability for demanding applications, such as those involving cyclic loading. Following previous work that studied Polylactic Acid (PLA) and Polyethylene Terephthalate Glycol-modified (PETG) under experimental fatigue testing, this study examines the fatigue behaviour of other current 3D-printed polymeric materials, namely Acrylonitrile Styrene Acrylate (ASA), Polycarbonate (PC), Polyamide 12 (Nylon 12), and Polycarbonate–Acrylonitrile Butadiene Styrene (blend) (PC-ABS), for which fatigue data remain limited or even non-existent. The findings revealed performance differences on Tensile Strength (σR), Young’s Modulus and Ultimate Strain among tensile specimens made from these materials and characterised S-N curves for both high-cycle (HCF) and low-cycle (LCF) fatigue regimes at room temperature, with a tensile load ratio (R = 0.05). These results establish relationships among fatigue limit and quasi-static mechanical properties, namely 25% × σr for ASA (8 MPa), 7% × σr for PC (3.6 MPa), 17% × σr for Nylon 12 (7.4 MPa), and 15% × σr for PC-ABS (4.7 MPa), as well as between mechanical properties and preliminary potential biomechanical applications. Main conclusions were further supported by micro-computed tomography (micro-CT), which revealed levels of porosity in between 4% and 11%, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR).
Design of a Video Otoscope Prototype with an Integrated Scanner for Hearing Aid Direct Digital Manufacturing: A Preliminary Study Cândida Malça, Francisco Ganhão, António Carvalho Santos, Carla Silva, Carla Moura Applied Sciences Switzerland, 2025 In the current landscape of hearing rehabilitation, ear mold manufacturing typically involves the injection of silicone into the external ear canal (EEC) of each patient. This invasive procedure poses several risks, including the potential for silicone residue retention and tympanic membrane perforation, which may necessitate surgical intervention. To mitigate these risks, we present the design of a video otoscope that integrates a scanner capable of capturing high-precision, real-time images of the EEC’s geometry. The developed device allows (i) the generation of a 3D CAD model leading to the direct, quick, and low-cost production of customized hearing aids using 3D printing and (ii) the establishment of medical protocols for carrying out diagnoses and monitoring of hearing pathology evolution using methodologies based on Artificial Intelligence. Furthermore, the use of customized hearing aids that allow the application of Rhythmic Auditory Stimulation (RAS) and music therapy enhances audiology as an alternative and innovative way to treat cognitive and degenerative diseases, as well as pathological disorders.
Material Performance Evaluation for Customized Orthoses: Compression, Flexural, and Tensile Tests Combined with Finite Element Analysis Daniela Trindade, Rachel Habiba, Cristiana Fernandes, André A. Costa, Rui Silva, et al. Polymers, 2024 Orthoses are commonly used for treating injuries to improve the quality of life of patients, with customized orthoses offering significant benefits. Additive manufacturing, especially fused deposition modelling, enhances these benefits by providing faster, more precise, and more comfortable orthoses. The present study evaluates nine polymeric materials printed in horizontal and vertical directions by assessing their performance through compressive, flexural, and tensile tests. Among all materials, polycarbonate, polylactic acid, and ULTEMTM 1010 showed the most promising results, not only because they had the highest mechanical values, but also due to their minimal or no difference in performance between printing directions, making them advantageous in orthoses fabrication. Based on this, a finite element model of an ankle–foot orthosis was developed to simulate the deformation, strain, and stress fields under static conditions. The findings aim to optimize material selection for orthotic fabrication, where ULTEMTM 1010 is presented as the material with improved performance and durability.
Comparative Analysis of Impact Strength among Various Polymeric Materials for Orthotic Production Rachel Habiba, Ana Amaro, Daniela Trindade, Carla Moura, Rui Silva, et al. Polymers, 2024 Orthotic devices play an important role in medical treatment, addressing various pathologies and promoting patient recovery. Customization of orthoses to fit individual patient morphologies and needs is essential for optimal functionality and patient comfort. The advent of additive manufacturing has revolutionized the biomedical field, offering advantages such as cost reduction, increased personalization, and enhanced dimensional adaptability for orthotics manufacturing. This research focuses on the impact strength of nine polymeric materials printed by additive manufacturing, including an evaluation of the materials’ performance under varying conditions comprising different printing directions (vertical and horizontal) and exposure to artificial sweat for different durations (0 days, 24 days, and 189 days). The results showed that Nylon 12 is good for short-term (24 days) immersion, with absorbed energies of 78 J and 64 J for the vertical and horizontal directions, whereas Polycarbonate (PC) is good for long-term immersion (189 days), with absorbed energies of 66 J and 78 J for the vertical and horizontal directions. Overall, the findings contribute to a better understanding of the suitability of these materials for biomedical applications, considering both short-term and long-term exposure to physiological and environmental conditions.
Mechanical Properties of Additively Manufactured Polymeric Materials—PLA and PETG—For Biomechanical Applications Rui F. Martins, Ricardo Branco, Miguel Martins, Wojciech Macek, Zbigniew Marciniak, et al. Polymers, 2024 The study presented herein concerns the mechanical properties of two common polymers for potential biomedical applications, PLA and PETG, processed through fused filament fabrication (FFF)—Material Extrusion (ME). For the uniaxial tension tests carried out, two printing orientations—XY (Horizontal, H) and YZ (Vertical, V)—were considered according to the general principles for part positioning, coordinates, and orientation typically used in additive manufacturing (AM). In addition, six specimens were tested for each printing orientation and material, providing insights into mechanical properties such as Tensile Strength, Young’s Modulus, and Ultimate Strain, suggesting the materials’ potential for biomedical applications. The experimental results were then compared with correspondent mechanical properties obtained from the literature for other polymers like ASA, PC, PP, ULTEM 9085, Copolyester, and Nylon. Thereafter, fatigue resistance curves (S-N curves) for PLA and PETG, printed along 45°, were determined at room temperature for a load ratio, R, of 0.2. Scanning electron microscope observations revealed fibre arrangements, compression/adhesion between layers, and fracture zones, shedding light on the failure mechanisms involved in the fatigue crack propagation of such materials and giving design reference values for future applications. In addition, fractographic analyses of the fatigue fracture surfaces were carried out, as well as X-ray Computed Tomography (XCT) and Thermogravimetric (TGA)/Differential Scanning Calorimetric (DSC) tests.
Fatigue behaviour and life prediction of L-PBF-processed maraging steel under variable-amplitude loading R Branco, Z Marciniak, P Prates, B Das, RF Martins, C Malça Archives of Civil and Mechanical Engineering 26 (2), 32 , 2026 2026
Mechanical, Fatigue, and Thermal Characterization of ASA, Nylon 12, PC, and PC-ABS Manufactured by Fused Filament Fabrication (FFF) Â Rodrigues, R Branco, M Franco, R Silva, C Malça, RF Martins Polymers 18 (2), 302 , 2026 2026 Citations: 2
The influence of printing strategies on the fatigue crack growth behaviour of an additively manufactured Ti6Al4V Grade 23 titanium alloy RF Martins, R Branco, J Camacho, W Macek, Z Marciniak, A Silva, ... International Journal of Fatigue 197, 108942 , 2025 2025 Citations: 9
Manufacturing and Numerical Validation of the Innovative Double-Chamber Perfusion Bioreactor for Osteochondral Tissue Repair M Loureiro, D Palaio, C Moura, R Cordeiro, AC Santos, C Malça International Conference Innovation in Engineering, 215-225 , 2025 2025
Design of a Double-Chamber Perfusion Bioreactor for Osteochondral Tissue Repair: An Innovative Concept C Moura, M Loureiro, D Palaio, R Cordeiro, AC Santos, C Malça International Conference Innovation in Engineering, 455-467 , 2025 2025
Design of a Video Otoscope Prototype with an Integrated Scanner for Hearing Aid Direct Digital Manufacturing: A Preliminary Study C Malça, F Ganhão, AC Santos, C Silva, C Moura Applied Sciences 15 (5), 2280 , 2025 2025
Material Performance Evaluation for Customized Orthoses D Trindade, R Habiba, C Fernandes, AA Costa, R Silva, N Alves, ... 2024
Material performance evaluation for customized orthoses: Compression, flexural, and tensile tests combined with finite element analysis D Trindade, R Habiba, C Fernandes, AA Costa, R Silva, N Alves, ... Polymers 16 (18), 2553 , 2024 2024 Citations: 13
Mechanical properties of additively manufactured polymeric materials—PLA and PETG—for biomechanical applications RF Martins, R Branco, M Martins, W Macek, Z Marciniak, R Silva, ... Polymers 16 (13), 1868 , 2024 2024 Citations: 43
Comparative analysis of impact strength among various polymeric materials for orthotic production R Habiba, A Amaro, D Trindade, C Moura, R Silva, A Antão, RF Martins, ... Polymers 16 (13), 1843 , 2024 2024 Citations: 8
Exploring the potential of recycled polymers for 3D printing applications: a review R Djonyabe Habiba, C Malça, R Branco Materials 17 (12), 2915 , 2024 2024 Citations: 33
Cyclic deformation and fracture behaviour of additive manufactured maraging steel under variable-amplitude loading Z Marciniak, R Branco, W Macek, M Dobrzyński, C Malça Theoretical and Applied Fracture Mechanics 129, 104207 , 2024 2024 Citations: 7
Fatigue behaviour of SLM maraging steel under variable-amplitude loading Z Marciniak, R Branco, W Macek, C Malça Procedia Structural Integrity 56, 131-137 , 2024 2024 Citations: 4
The influence of printing strategies on fatigue crack growth behavior of an additively manufactured AISI 316L stainless steel J Camacho, RF Martins, R Branco, A Raimundo, C Malça Fatigue & Fracture of Engineering Materials & Structures 46 (10), 3953-3965 , 2023 2023 Citations: 9
As experiências, perceções e expectativas no uso da gamificação e exergaming nas pessoas em processo de reabilitação pós-evento H Neves, A Cruz, V Parola, RA Bernardes, R Cardoso, M Pimentel, ... RevSALUS-Revista Científica Internacional da Rede Académica das Ciências da … , 2023 2023
Ablefit-sistema avançado de reabilitação: resultados preliminares de um estudo pré-clínico A Cruz, V Parola, H Neves, RA Bernardes, R Cardoso, M Pimentel, ... RevSALUS-Revista Científica Internacional da Rede Académica das Ciências da … , 2023 2023 Citations: 1
Ablefit-sistema avançado de reabilitação: processo de desenvolvimento V Parola, A Cruz, H Neves, RA Bernardes, R Cardoso, M Pimentel, ... RevSALUS-Revista Científica Internacional da Rede Académica das Ciências da … , 2023 2023 Citations: 1
Pre-clinical study of a customized rehabilitation device prototype for patients with immobility syndrome T Ribeiro, L Roseiro, M Silva, F Santos, R Bernardes, R Cardoso, ... International Workshop on Medical and Service Robots, 90-98 , 2023 2023 Citations: 1
Impact Resistance of Additively Manufactured Polymeric Materials for Biomedical Applications R Habiba, A Amaro, C Moura, R Silva, D Trindade, A Antão, R Martins, ... Congress of the Portuguese Society of Biomechanics, 333-341 , 2023 2023 Citations: 3
Design of a customized rehabilitation device for patients with prolonged immobility syndrome C Malça, T Ribeiro, M Silva, F Santos, R Bernardes, A Cruz, W Xavier, ... Congress of the Portuguese Society of Biomechanics, 207-217 , 2023 2023 Citations: 1
MOST CITED SCHOLAR PUBLICATIONS
A critical overview of internal and external cylinder contact force models CM Pereira, AL Ramalho, JA Ambrósio Nonlinear Dynamics 63 (4), 681-697 , 2011 2011 Citations: 186
An enhanced cylindrical contact force model C Pereira, A Ramalho, J Ambrosio Multibody System Dynamics 35 (3), 277-298 , 2015 2015 Citations: 91
Application of a hybrid additive manufacturing methodology to produce a metal/polymer customized dental implant M Silva, R Felismina, A Mateus, P Parreira, C Malça Procedia Manufacturing 12, 150-155 , 2017 2017 Citations: 89
Design and analysis of buoy geometries for a wave energy converter PJBFN Beirao, CM dos Santos Pereira Malça International Journal of Energy and Environmental Engineering 5 (2), 91 , 2014 2014 Citations: 73
Optimization of a wood plastic composite for architectural applications G Martins, F Antunes, A Mateus, C Malça Procedia Manufacturing 12, 203-220 , 2017 2017 Citations: 68
An additive manufacturing solution to produce big green parts from tires and recycled plastics J Domingues, T Marques, A Mateus, P Carreira, C Malça Procedia Manufacturing 12, 242-248 , 2017 2017 Citations: 68
Fabrication of poly (ε‐caprolactone) scaffolds reinforced with cellulose nanofibers, with and without the addition of hydroxyapatite nanoparticles P Morouço, S Biscaia, T Viana, M Franco, C Malça, A Mateus, C Moura, ... BioMed Research International 2016 (1), 1596157 , 2016 2016 Citations: 68
Recovery and evaluation of cellulose from agroindustrial residues of corn, grape, pomegranate, strawberry-tree fruit and fava M Vallejo, R Cordeiro, PAN Dias, C Moura, M Henriques, IJ Seabra, ... Bioresources and Bioprocessing 8 (1), 25 , 2021 2021 Citations: 67
Dynamics of chain drives using a generalized revolute clearance joint formulation C Pereira, J Ambrósio, A Ramalho Mechanism and machine Theory 92, 64-85 , 2015 2015 Citations: 62
A methodology for the generation of planar models for multibody chain drives CM Pereira, JA Ambrósio, AL Ramalho Multibody System Dynamics 24 (3), 303-324 , 2010 2010 Citations: 56
Applicability domain of internal cylindrical contact force models C Pereira, A Ramalho, J Ambrosio Mechanism and Machine Theory 78, 141-157 , 2014 2014 Citations: 53
Mechanical properties of additively manufactured polymeric materials—PLA and PETG—for biomechanical applications RF Martins, R Branco, M Martins, W Macek, Z Marciniak, R Silva, ... Polymers 16 (13), 1868 , 2024 2024 Citations: 43
Cork plastic composite optimization for 3D printing applications F Brites, C Malça, F Gaspar, JF Horta, MC Franco, S Biscaia, A Mateus Procedia Manufacturing 12, 156-165 , 2017 2017 Citations: 42
Physical rehabilitation programs for bedridden patients with prolonged immobility: a scoping review R Cardoso, V Parola, H Neves, RA Bernardes, FM Duque, CA Mendes, ... International journal of environmental research and public health 19 (11), 6420 , 2022 2022 Citations: 39
Exploring the potential of recycled polymers for 3D printing applications: a review R Djonyabe Habiba, C Malça, R Branco Materials 17 (12), 2915 , 2024 2024 Citations: 33
Planar roller chain drive dynamics using a cylindrical contact force model J Ambrosio, C Malça, A Ramalho Mechanics Based Design of Structures and Machines 44 (1-2), 109-122 , 2016 2016 Citations: 30
Rehabilitation programs for bedridden patients with prolonged immobility: a scoping review protocol V Parola, H Neves, FM Duque, RA Bernardes, R Cardoso, CA Mendes, ... International Journal of Environmental Research and Public Health 18 (22), 12033 , 2021 2021 Citations: 27
Development of an additive manufacturing system for the deposition of thermoplastics impregnated with carbon fibers M Reis Silva, AM Pereira, N Alves, G Mateus, A Mateus, C Malça Journal of Manufacturing and Materials Processing 3 (2), 35 , 2019 2019 Citations: 27
Study on the aerodynamic behavior of a UAV with an applied seeder for agricultural practices R Felismina, M Silva, A Mateus, C Malça AIP Conference Proceedings 1836 (1), 020049 , 2017 2017 Citations: 21
An alternative method to produce metal/plastic hybrid components for orthopedics applications M Silva, A Mateus, D Oliveira, C Malça Proceedings of the Institution of Mechanical Engineers, Part L: Journal of … , 2017 2017 Citations: 17