Specimen Design and Characterization for Thin-Walled Components in Very-High-Cycle Fatigue Regime: Aluminium 6082 Case Study Felipe Klein Fiorentin, Rita Dantas, Jorge Wolfs Gil, Aida Beatriz Moreira, Francisco Matos, et al. Materials, 2026 Rapid characterization of high-cycle fatigue behaviour is of great interest, since conventional methods for developing S-N curves for longer fatigue lives are both costly in time and financial resources. Ultrasonic fatigue testing offers a promising alternative by enabling S-N curve evaluation in a fraction of the time, often hundreds of times faster, due to its high testing frequencies. Nevertheless, this technique presents specific challenges, including material overheating and limitations in specimens’ geometry. Most ultrasonic fatigue studies employ hourglass specimens; however, this geometry restricts the testing of sheets and thin-walled components, which are increasingly used for their reduced mass and high stiffness-to-mass ratio. To overcome this limitation, the present work introduces a methodology for designing and testing flat specimens and corresponding gripping systems tailored to such components. The procedure is demonstrated for an aluminium alloy (6082), and preliminary experimental fatigue results are presented and compared with literature.
On the Specimen Design, Physical Properties and Geometry Effect on Heat Generation and Thermal Gradient in Ultrasonic Fatigue Felipe Klein Fiorentin, Rita Dantas, Jorge Wolfs Gil, Andrea Piga Carboni, Thiago Antonio Fiorentin, et al. Machines, 2025 Performing fatigue characterisation is often an expensive task, being both time consuming and expensive. Taking that into account, ultrasonic fatigue testing is an interesting solution, since it can be thousands of times faster than traditional experiments. In ultrasonic fatigue testing, excitation frequencies are in the order of magnitude of 20 kHz, while common fatigue testing frequencies are typically approximately a few hundreds of Hz. Although promising, ultrasonic fatigue testing has some challenges, like high strain rates, heat generation and complex specimen design. Regarding the latter, since the working principle of ultrasonic fatigue tests relies on exciting the specimen in one of its natural frequencies, finding a specimen geometry to resonate at this given frequency might be challenging. Additionally, some materials often present challenges associated with high temperature during tests. The goal of this paper is to provide guidelines for specimen design, encompassing the effects of critical factors and their impact on important test parameters, like temperature and dimensions. The proposed methodology developed a parameter able to quantify the heat generation severity during ultrasonic fatigue testing for several materials based on their physical properties. Moreover, the effects of the geometry and material properties in the temperature during loading cycles, with special focus on thermal gradients were enumerated.
Reducing Railway Track Vibrations by Applying Particle-Damping Systems Felipe Fiorentin, Cristian Piehowiak, Anelize Salvi, Yesid Asaff, Andrea Carboni, et al. Applied Sciences Switzerland, 2025 The wheel–rail contact is an intrinsic characteristic of rail transport. This contact is one of the main reasons why rails are so efficient for transportation, mainly due to the very low friction coefficient between them and the wheels. However, this strong argument also leads to a disadvantage: the wheel contact is also associated with excessive vibration and noise, which have a strong impact on the passengers’ comfort and especially the surrounding community. These noises and vibrations impact the public in several ways, like disturbing sleep, increasing stress and heart-associated diseases. The main objective of the present work is to investigate the rail vibration attenuation by applying particle dampers. Four different particles will be studied, and their effectiveness in reducing the rail vibrations will be analysed. Promising results were found, where under certain conditions, the particle dampers, such as lead and magnetite particles, were able to reduce peak vibration levels by more than an order of magnitude. The application of this system may have a strong impact on the communities using and in the vicinity of rail systems by reducing the noise and vibration, consequently improving people’s health and well-being.
Probabilistic Modelling of Fatigue Behaviour of 51CrV4 Steel for Railway Parabolic Leaf Springs Vítor M. G. Gomes, Felipe K. Fiorentin, Rita Dantas, Filipe G. A. Silva, José A. F. O. Correia, et al. Metals, 2025 The longevity of railway vehicles is an important factor in their mechanical and structural design. Fatigue is a major issue that affects the durability of railway components, and therefore, knowledge of the fatigue resistance characteristics of critical components, such as the leaf springs, must be extensively investigated. This research covers the fatigue resistance of chromium–vanadium alloy steel, usually designated as 51CrV4, from the high-cycle regime (HCF) (103–104) up to very high-cycle fatigue (VHCF) (109) under the bending loading conditions typical of leaf springs and under uniaxial tension/compression loading, respectively, for a stress ratio, Rσ, of −1. Different test frequencies were considered (23, 150, and 20,000 Hz) despite the material not exhibiting a relatively significant frequency effect. In order to create a new fatigue prediction model, two prediction models, the Basquin SN linear regression model and the Castillo–Fernandez–Cantelli (CFC) model, were evaluated. According to the analysis carried out, the CFC model provided a better prediction of the fatigue failures than the SN model, especially when outlier failure data were considered. The investigation also examined the failure modes, observing multiple cracks for higher loads and single cracks that initiated on the surface or from internal inclusions at lower loading. The present investigation aims to provide a fatigue resistance prediction model encompassing the HCF and VHCF regions for the fatigue design of railway wagon leaf springs, or even for other components made of 51CrV4 with a tempered martensitic microstructure.
Particle Dampers for Vibration Reduction Designed for a Motorcycle Handlebar Felipe Klein Fiorentin, Vítor Gustavo Gomes Catão, Anelize Zomkowski Salvi, Andrea Piga Carboni, Thiago Antonio Fiorentin Shock and Vibration, 2025 Health problems caused by excessive handle–arm vibrations (HAV) are very frequent in professionals working with machines that generate cyclic loads, like some hand tools (chainsaws, impulse tools and hammer drills, e.g.) and vehicles (like tractors and motorcycles). HAV may lead to several health problems in different body systems, like vascular, neurological and musculoskeletal disorders. The risk of developing HAV syndromes increases with the vibration amplitudes and also with the exposure times. Professionals working with motorcycles (like delivery services, police officers and athletes) are often exposed to excessive vibrations for long periods of time and are prone to have health problems associated with their occupational exposure to vibrations. Unfortunately, excessive vibrations are presented in a wide range of motorcycles, ranging from the smallest ones (typically due to an intrinsic unbalance of a single cylinder motor) to the largest ones (due to large vibration generated by large displacement engines). In order to address the HAV in motorcycles, the present work encompasses studies of different particle damping (PD) systems, analysing which one is able minimize the vibrations (and the health problems associated with it) in a motorcycle handlebar. Positive results were obtained using the designed particle dampers; in some cases, the vibration absorbers were able to reduce peak vibration by a factor of 6 (at frequencies around 60 Hz and for sweep sine excitation), when compared to the standard industry solution (handlebar counterweights, often referred as handlebar stabilizers).
Relation Between Striations Spacing and Fatigue Crack Growth Rates for Additive Manufactured Inconel 625 Felipe Klein Fiorentin, Rita Dantas, Roya Darabi, Grzegorz Lesiuk, Miguel Figueiredo, et al. Fatigue and Fracture of Engineering Materials and Structures, 2025 The principles of the mechanisms for fatigue crack propagation in metals have been established several decades ago. By definition, fatigue might be summarized as a damage process imparted to a material under the action of cyclic loads. The relation between fatigue crack growth rates (FCGRs) and formation of striation marks has been a controversial topic. Some authors stated that, in certain fatigue regimes, several fatigue cycles are required to form a single striation. The disagreement found was the motivation for the present work. This study's main goal is to provide a comparison between the striation spacing and the respective FCGR. These analyses will be performed in a Nickel superalloy, Inconel 625, obtained via directed energy deposition. Investigation of the striations spacing are compared with data obtained from FCGR tests. A good agreement between striation spacing and FCGRs was found to intermediate and large values of stress intensity factor.
Quantitative fractography and the fatigue crack propagation behaviour of DED’ed 18Ni300 Maraging steel J Gil, F Fiorentin, F Vaz, B Silva, A Reis Portuguese Conference on Fracture 2026—Book of Abstracts, 33 , 2026 2026
Multiaxial fatigue performance of S690 QL steel in HCF and VHCF regimes R Dantas, GP Cipriano, A Dantas, F Fiorentin, J Correia, A de Jesus Portuguese Conference on Fracture 2026—Book of Abstracts, 57 , 2026 2026
Railway noise and vibration mitigation: a review of technologies and applications F Klein Fiorentin, A Piga Carboni, A Prieto, FC Sousa, ... Transport, 1-8 , 2026 2026
Specimen Design and Characterization for Thin-Walled Components in Very-High-Cycle Fatigue Regime: Aluminium 6082 Case Study F Klein Fiorentin, R Dantas, J Wolgs Gil, AB Moreira, F Matos, ... Materials 19 (2), 273 , 2026 2026
Investigation of Particulate Matter Emissions from Brake Pads of Light-Duty Vehicles: A Comparative Analysis of Friction Material Compositions VGG Catão, AR Machado, FK Fiorentin, JPA Silva, LG Bernardino, ... SAE Brasil 2025 Congress 380454 , 2025 2025
Avaliação de métodos para caracterização do material particulado emitido por sistemas de freio AR MACHADO, VGG CATÃO, MHP LOPES, LM KOLB, FA FERREIRA, ... Engineering Proceedings 12 (1), 453-458 , 2025 2025
Particle Dampers for Vibration Reduction Designed for a Motorcycle Handlebar FK Fiorentin, VGG Catão, AZ Salvi, AP Carboni, TA Fiorentin Shock and Vibration 2025 (1), 6664167 , 2025 2025
Very high cycle fatigue behaviour of a structural steel for offshore applications under a biaxial stress state R Dantas, F Fiorentin, JAFO Correia, G Lesiuk, A de Jesus International Journal of Fatigue 199, 109083 , 2025 2025 Citations: 6
Advancing infrastructure resilience and safety in modern transport systems F Klein Fiorentin Proceedings of the Institution of Civil Engineers-Transport 178 (5), 303-304 , 2025 2025
Integrated Engineering and Ecology Approaches for Controlling Invasive Sun Coral AP Carboni, B Segal, AS Marques, HV Catarin, M Crivellaro, T Silveira, ... OCEANS 2025 Brest, 1-7 , 2025 2025
On the specimen design, physical properties and geometry effect on heat generation and thermal gradient in ultrasonic fatigue F Klein Fiorentin, R Dantas, J Wolfs Gil, A Piga Carboni, TA Fiorentin, ... Machines 13 (5), 380 , 2025 2025 Citations: 5
Reducing Railway Track Vibrations by Applying Particle-Damping Systems FK Fiorentin, C Piehowiak, AZ Salvi, YE Asaff, AP Carboni, ... Applied Sciences 15 (9), 5014 , 2025 2025 Citations: 2
Probabilistic Modelling of Fatigue Behaviour of 51CrV4 Steel for Railway Parabolic Leaf Springs VMG Gomes, FK Fiorentin, R Dantas, FGA Silva, JAFO Correia, ... Metals 15 (2), 152 , 2025 2025 Citations: 4
Relation Between Striations Spacing and Fatigue Crack Growth Rates for Additive Manufactured Inconel 625 FK Fiorentin, R Dantas, R Darabi, G Lesiuk, M Figueiredo, PT de Castro, ... Fatigue & Fracture of Engineering Materials & Structures 48 (1), 454-466 , 2024 2024 Citations: 9
Notch sensitivity of a structural steel under VHCF R Dantas, M Gouveia, FGA Silva, F Fiorentin, J Correia, G Lesiuk, A Reis, ... PCF 2024, 11 , 2024 2024
Effect of heat accumulation on the microstructural evolution in inconel 625 superalloy printed by ded process O Emadinia, F Zafar, F Fiorentin, A Reis Procedia Structural Integrity 53, 278-284 , 2024 2024 Citations: 4
Notch effect in very high-cycle fatigue behaviour of a structural steel R Dantas, M Gouveia, FGA Silva, F Fiorentin, JAFO Correia, G Lesiuk, ... International Journal of Fatigue 177, 107925 , 2023 2023 Citations: 25
High-Cycle and Ultra-High Cycle Fatigue Behaviour of Directed Energy Deposited Inconel 625 FK Fiorentin Universidade do Porto , 2023 2023 Citations: 4
A predictive methodology for temperature, heat generation and transfer in gigacycle fatigue testing F Klein Fiorentin, L Reis, G Lesiuk, A Reis, A de Jesus Metals 13 (3), 492 , 2023 2023 Citations: 8
Fatigue assessment of Inconel 625 produced by directed energy deposition from miniaturized specimens F Klein Fiorentin, D Maciel, J Gil, M Figueiredo, F Berto, A de Jesus Metals 12 (1), 156 , 2022 2022 Citations: 20
MOST CITED SCHOLAR PUBLICATIONS
Experimental study of a hybrid wave energy converter integrated in a harbor breakwater P Rosa-Santos, F Taveira-Pinto, D Clemente, T Cabral, F Fiorentin, ... Journal of Marine Science and Engineering 7 (2), 33 , 2019 2019 Citations: 58
Notch effect in very high-cycle fatigue behaviour of a structural steel R Dantas, M Gouveia, FGA Silva, F Fiorentin, JAFO Correia, G Lesiuk, ... International Journal of Fatigue 177, 107925 , 2023 2023 Citations: 25
Fatigue assessment of Inconel 625 produced by directed energy deposition from miniaturized specimens F Klein Fiorentin, D Maciel, J Gil, M Figueiredo, F Berto, A de Jesus Metals 12 (1), 156 , 2022 2022 Citations: 20
Experimental and computational analysis of additively manufactured tensile specimens: assessment of localized-cooling rate and ductile fracture using the Gurson–Tvergaard … R Darabi, E Azinpour, FK Fiorentin, MJ Abarca, J Cesar de Sa, J Dzugan Proceedings of the Institution of Mechanical Engineers, Part L: Journal of … , 2021 2021 Citations: 17
Fatigue behavior of metallic components obtained by topology optimization for additive manufacturing F Fiorentin, B Oliveira, J Pereira, J Correia, AMP de Jesus, F Berto Fracture and Structural Integrity 15 (55), 119-135 , 2021 2021 Citations: 11
Relation Between Striations Spacing and Fatigue Crack Growth Rates for Additive Manufactured Inconel 625 FK Fiorentin, R Dantas, R Darabi, G Lesiuk, M Figueiredo, PT de Castro, ... Fatigue & Fracture of Engineering Materials & Structures 48 (1), 454-466 , 2024 2024 Citations: 9
A predictive methodology for temperature, heat generation and transfer in gigacycle fatigue testing F Klein Fiorentin, L Reis, G Lesiuk, A Reis, A de Jesus Metals 13 (3), 492 , 2023 2023 Citations: 8
A MODEL UPDATING METHOD FOR PLATE ELEMENTS USING PARTICLE SWARM OPTIMIZATION (PSO), MODELING THE BOUNDARY FLEXIBILITY, INCLUDING UNCERTAINTIES ON MATERIAL AND DIMENSIONAL … D NEGRI, FK FIORENTIN, JM CRICHIGNO FILHO Latin American Journal of Solids and Structures 15 (10), 1-18 , 2018 2018 Citations: 7
Very high cycle fatigue behaviour of a structural steel for offshore applications under a biaxial stress state R Dantas, F Fiorentin, JAFO Correia, G Lesiuk, A de Jesus International Journal of Fatigue 199, 109083 , 2025 2025 Citations: 6
On the specimen design, physical properties and geometry effect on heat generation and thermal gradient in ultrasonic fatigue F Klein Fiorentin, R Dantas, J Wolfs Gil, A Piga Carboni, TA Fiorentin, ... Machines 13 (5), 380 , 2025 2025 Citations: 5
Very high cycle fatigue behaviour of S690 structural steel R Dantas, M Gouveia, FGA Silva, F Fiorentin, A de Jesus, J Correia, ... Procedia Structural Integrity 42, 1676-1683 , 2022 2022 Citations: 5
Probabilistic Modelling of Fatigue Behaviour of 51CrV4 Steel for Railway Parabolic Leaf Springs VMG Gomes, FK Fiorentin, R Dantas, FGA Silva, JAFO Correia, ... Metals 15 (2), 152 , 2025 2025 Citations: 4
Effect of heat accumulation on the microstructural evolution in inconel 625 superalloy printed by ded process O Emadinia, F Zafar, F Fiorentin, A Reis Procedia Structural Integrity 53, 278-284 , 2024 2024 Citations: 4
High-Cycle and Ultra-High Cycle Fatigue Behaviour of Directed Energy Deposited Inconel 625 FK Fiorentin Universidade do Porto , 2023 2023 Citations: 4
Numerical modeling and prediction of residual stresses in AISI 316L and 18Ni300 steels produced by selective laser melting J Gil, M Pires, F Fiorentin, M Vaz, A Castanhola, M Parente, A de Jesus Procedia Structural Integrity 34, 6-12 , 2021 2021 Citations: 4
Reducing Railway Track Vibrations by Applying Particle-Damping Systems FK Fiorentin, C Piehowiak, AZ Salvi, YE Asaff, AP Carboni, ... Applied Sciences 15 (9), 5014 , 2025 2025 Citations: 2
MODEL UPDATING USING SUPPORT STIFFNESS VARIATION APPLYING PARTICLE SWARM OPTIMIZATION (PSO) D Negri, F Fiorentin, JMF Crichigno MECSOL 2017, 14 , 2017 2017 Citations: 1
Quantitative fractography and the fatigue crack propagation behaviour of DED’ed 18Ni300 Maraging steel J Gil, F Fiorentin, F Vaz, B Silva, A Reis Portuguese Conference on Fracture 2026—Book of Abstracts, 33 , 2026 2026
Multiaxial fatigue performance of S690 QL steel in HCF and VHCF regimes R Dantas, GP Cipriano, A Dantas, F Fiorentin, J Correia, A de Jesus Portuguese Conference on Fracture 2026—Book of Abstracts, 57 , 2026 2026
Railway noise and vibration mitigation: a review of technologies and applications F Klein Fiorentin, A Piga Carboni, A Prieto, FC Sousa, ... Transport, 1-8 , 2026 2026
