“…Figure 6 plots the cyclic stress amplitude against the elastic strain amplitude using the unloading moduli measured in the tests (dash-dotted line). The relation between these two variables, as already demonstrated in the literature [20][21][22], can be defined from a power law relationship similar to that of Equation (1). The coefficients, obtained using a best fitting technique with a correlation factor of 0.998, are listed in Table 4.…”
Section: Cyclic Stress-strain Responsementioning
confidence: 97%
“…Selective laser melting (SLM) is one promising technology able to meet these goals, allowing the production of complex geometries directly from three-dimensional CAD (computer aided design) models in short time frames and at low cost [1].…”
Selective laser melting has received a great deal of attention in recent years. Nevertheless, research has been mainly focused on the technical issues and their relationship with the final microstructure and monotonic properties. Fatigue behaviour has rarely been addressed, and the emphasis has been placed on high-cycle regimes. The aim of this paper is, therefore, to study, in a systematic manner, the cyclic plastic behaviour of AISI 18Ni300 maraging steel manufactured by selective laser melting. For this purpose, low-cycle fatigue tests, under fully-reversed strain-controlled conditions, with strain amplitudes ranging from 0.3% to 1.0%, were performed. After testing, fracture surfaces were examined by scanning electron microscopy to identify the main fatigue damage mechanisms. The analysis of results showed a non-Masing material, with a slight strain-softening behaviour, and non-linear response in both the elastic and plastic regimes. In addition, this steel exhibited a very low transition life of about 35 reversals, far below the values of conventional materials with equivalent monotonic mechanical properties, which can be attributed to the combination of high strength and low ductility. The total strain energy density, irrespective of strain amplitude, revealed itself to be a quite stable parameter throughout the lifetime. Finally, the SEM analysis showed for almost all the tested samples cracks initiated from the surface and inner defects which propagated through the rest of the cross section. A ductile/brittle fracture, with a predominance of brittle fracture, was observed in the samples, owing to the presence of defects which make it easier to spread the microcracks.
“…Figure 6 plots the cyclic stress amplitude against the elastic strain amplitude using the unloading moduli measured in the tests (dash-dotted line). The relation between these two variables, as already demonstrated in the literature [20][21][22], can be defined from a power law relationship similar to that of Equation (1). The coefficients, obtained using a best fitting technique with a correlation factor of 0.998, are listed in Table 4.…”
Section: Cyclic Stress-strain Responsementioning
confidence: 97%
“…Selective laser melting (SLM) is one promising technology able to meet these goals, allowing the production of complex geometries directly from three-dimensional CAD (computer aided design) models in short time frames and at low cost [1].…”
Selective laser melting has received a great deal of attention in recent years. Nevertheless, research has been mainly focused on the technical issues and their relationship with the final microstructure and monotonic properties. Fatigue behaviour has rarely been addressed, and the emphasis has been placed on high-cycle regimes. The aim of this paper is, therefore, to study, in a systematic manner, the cyclic plastic behaviour of AISI 18Ni300 maraging steel manufactured by selective laser melting. For this purpose, low-cycle fatigue tests, under fully-reversed strain-controlled conditions, with strain amplitudes ranging from 0.3% to 1.0%, were performed. After testing, fracture surfaces were examined by scanning electron microscopy to identify the main fatigue damage mechanisms. The analysis of results showed a non-Masing material, with a slight strain-softening behaviour, and non-linear response in both the elastic and plastic regimes. In addition, this steel exhibited a very low transition life of about 35 reversals, far below the values of conventional materials with equivalent monotonic mechanical properties, which can be attributed to the combination of high strength and low ductility. The total strain energy density, irrespective of strain amplitude, revealed itself to be a quite stable parameter throughout the lifetime. Finally, the SEM analysis showed for almost all the tested samples cracks initiated from the surface and inner defects which propagated through the rest of the cross section. A ductile/brittle fracture, with a predominance of brittle fracture, was observed in the samples, owing to the presence of defects which make it easier to spread the microcracks.
“…DMLS technology has moved the concept of Rapid Prototyping [2][3][4] into the realm of real time manufacturing of metal components which have been proven for use within some of the most demanding environments and applications to be found [5][6][7]. One attractive aspect of DMLS is that design and production costs do not rise exponentially with the potential complexity of the design [8].…”
In Formula 1 racing, there is a strong motive for reducing component weight and thereby improving efficiency. This paper demonstrates the advantages Additive Manufacturing brings to the production of hydraulic components. The Direct Metal Laser Sintering (DMLS) production technique enables weight reductions to be attained by its geometric design freedom coupled with this material's attributes. The use of EOS Titanium Ti64 material for hydraulic components has been assessed by a hydraulic soak test at 25 MPa and no significant losses or failure occurred. The benefits to the efficiency of hydraulic flow have been measured using Particle Image Velocimetry (PIV) and the use of DMLS manufactured geometry has improved flow characteristics by 250% over that of the currently used techniques of manufacturing channels and bores.
“…Deckard preencheu em 1986 sua patente intitulada: "Método e equipamento para produção de peças por sinterização seletiva", tecnologia que permitiu o uso na AM de materiais que não apenas polímeros, tais quais metais, termoplásticos, cerâmicas, além de poder utilizar, também, polímeros de diversas naturezas (Bechthold et al, 2015;Deckard, 1989;Mackley, 2014;Strickland, 2016 (Santos et al, 2006).…”
Section: Antecedentesunclassified
“…Figura 24 -Modelo Laser Engineered Net Shaping (Santos et al, 2006;Wong e Hernandez, 2012) 3 Material Extrusion Esta categoria de processos contempla tecnologias que utilizam bocais injetores controlados por computador para, seletivamente, depositarem material moldável, em um fluxo contínuo (Vaezi et al, 2013), normalmente polímeros ou material a base de polímeros, para criar objetos tridimensionais (Bourell 2016).…”
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