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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.
- X-ray diffraction residual stress measurements for assessment of rolling contact fatigue behaviour of railway steelsPublication . Batista, António Castanhola; Nobre, João P.; Peixoto, Daniel F.C.; Ferreira, Luis A.A.; Castro, Paulo M.S.T. de; Coelho, Luís Manuel de JesusRolling contact fatigue twin-disc tests were performed on rail/wheel steels from Spanish high velocity trains (AVE). Residual stress profiles were determined using X-ray diffraction before and after cyclic loading. The evolution of residual stress profiles, due to cyclic loading, was analysed in order to study how they affect the rolling contact fatigue behaviour of these materials. This study is included in a major project where other related phenomena and materials’ properties have been studied.
- Residual stresses profiles of cladded austenitic stainless steel evaluated by X-ray diffraction and by incremental hole-drilling methodPublication . Marques, Maria José; Batista, António Castanhola; Coelho, Luís Manuel de Jesus; Nobre, João P.; Loureiro, AltinoThe samples studied in this paper were carried out using carbon steel plates, cladded on one of the faces with stainless steel filler metals by submerged arc welding (SAW). After cladding, the samples were submitted to post-weld heat treatments under different conditions and then stainless steel coating surfaces were milled and mechanically polished, as in the industrial application. The residual stress analysis was performed by X-ray diffraction (XRD) and incremental hole-drilling methods (IHD). The residual stress profiles showed different values in-depth in each sample, depending on the heat treatment. The hole-drilling method was applied in several points of each stainless steel sample surface and the results presented similar profiles of evolution. However, compressive stresses increase when the heat treatment temperature rises.
- Two experimental methods to determining stress-strain behavior of work-hardened surface layers of metallic componentsPublication . Nobre, João P.; Batista, A. C.; Coelho, Luís Manuel de Jesus; Dias, A. M.Two experimental methods to characterize the mechanical behavior of work-hardened surface layers of metallic materials, induced by mechanical surface treatments, are described and discussed. The study was conducted using two steels with different mechanical properties, subjected to a similar shot-peening treatment. To characterize the elastic–plastic behavior of the surface layers affected by shot-peening, the X-ray diffraction assisted four-point bending method (XRDABM) and the normalized hardness variation method (NHVM) were applied. The results were compared and discussed taking into account the advantages and disadvantages of both methods. Similar yield strength values of the treated surfaces were found by both proposed methods. Taking into account their measuring characteristics, these can be considered complementary methods.
- Wear and surface residual stress evolution on twin-disc tests of rail/wheel steelsPublication . Batista, António Castanhola; Peixoto, Daniel F.C.; Nobre, João P.; Coelho, Luís Manuel de Jesus; Ramos, Diogo Mesquita; Ferreira, Luis A.A.; Castro, Paulo M.S.T. deTwin disc tribological tests were performed in wheel and rail materials, with specimens taken from a Spanish AVE train wheel and a UIC60 rail, in a program intended to characterize their contact fatigue behavior. The X-ray diffraction technique was used to characterize the residual stress distribution at the initial and damaged stages, as well as in intermediate stages, since existing residual stresses in the surface layers of the railways steels and its evolution during contact loading can have a major influence on crack initiation and propagation.
- Experimental and numerical rolling contact fatigue study on the 32CrMoV13 steelPublication . Coelho, Luís Manuel de Jesus; Dias, A.; Lieurade, H. P.; Maitournam, H.The aim of this work is to study pure rolling contact fatigue in 32CrMoV13 quenching and tempering steel. The study involves both experimental and numerical work. The influence of the roughness and the residual stresses on the mechanisms and zones of cracking were studied. The results show a rapid reduction in roughness during the first minute of test but even so there will be specimen deterioration. The residual stress profile after rolling contact tests have high compression values in the surface and at a depth of approximately 240 μm, which is related with the Hertzian maximal shear stress. The numerical simulation of the Hertzian loading was used both to determine the elastic shakedown of thematerial and to apply a high-cycle multiaxial fatigue criterion. The threedimensional finite element analysis used in the numerical calculation includes elastic-linear kinematic hardening plastic material and allows the introduction of an initial residual stress state. Taking into account the elastoplastic load induced by the Hertz pressure, low-cycle fatigue tests were used to characterize the mechanical properties of the material. In order to validate the numerical simulation, the results of the calculation after elastic shakedown were compared with the values measured by X-ray diffraction after rolling contact tests. The results showed a reasonable agreement between calculated and measured stresses. The Dang Van high-cycle multiaxial fatigue criterion showed a good relationship with the experimental findings.
- Assessing shot-peening residual stresses by using the incremental hole-drilling technique and laser interferometry (DSPI)Publication . Nobre, João P.; Oliveira, Miguel; Albertazzi, Armando; Viotti, Matias; Batista, António Castanhola; Coelho, Luís Manuel de Jesus; Marques, Maria J.The incremental hole-drilling technique was applied to determine residual stress profiles in shot-peened steel layers. The accuracy of using an enhanced Digital Speckle Pattern Interferometry technique for measuring the strain relaxation arising around the drilled holes and, consequently, the in-depth residual stress distribution induced by shot-peening, was evaluated. The experimental results were systematically compared with those determined using standard electric strain-gauges. The X-ray diffraction technique was chosen as reference due to its high accuracy to determine shot-peening residual stresses.
- Evaluation of stress-strain behavior of surface treated steels by X-ray diffractionPublication . Coelho, Luís Manuel de Jesus; Batista, A. C.; Nobre, J. P.; Marques, M. J.X-ray diffraction assisted four-point bending method (XRDABM) enables to analyze the evolution of surface stress with the strain during bending of specimens. This experimental methodology was used to characterize the stressstrain behavior of two plasma nitriding steels, DIN 40 Cr Mn Mo 7 and DIN 32 Cr Mo V 13, with gradients of mechanical properties across the surface layers, allowing the characterization of the in-depth evolution of the local yield strength in the nitrided layer. The results show a significantly increase of the yield strength of the nitride layers and a good agreement between the in-depth evolution of the yield strength and the XRD peak breadth for the two nitrided steels.
- Evaluation of residual stresses induced by ultra-high-speed drilling in aluminium alloysPublication . Nobre, João P.; Guimarães, Ruben; Batista, António Castanhola; Marques, Maria José; Coelho, Luís Manuel de Jesus; Nau, Andreas; Scholtes, BertholdRolling contact fatigue twin-disc tests were performed on rail/wheel steels from Spanish high velocity trains (AVE). Residual stress profiles were determined using X-ray diffraction before and after cyclic loading. The evolution of residual stress profiles, due to cyclic loading, was analysed in order to study how they affect the rolling contact fatigue behaviour of these materials. This study is included in a major project where other related phenomena and materials’ properties have been studied.