36 documents found, page 1 of 4
Coupling μ-computed tomography and multi-scale modelling to assess the mechanic...
Cacho, L. M.; Neto, M. A.; Neto, D. M.; Vieira, M. T.The porosity defects arising in objects produced by metal Material Extrusion (MEX) additive manufacturing affect the macroscopic mechanical behaviour. This paper presents a new approach integrating μ-computed tomography (μXCT) and multi-scale finite element analysis to evaluate the mechanical performance of components fabricated by metal MEX. The porosity information from μXCT is mapped into the finite element ...
A comparison between FEM predictions and DIC results of crack tip displacement ...
Gómez Gonzáles, G.L.; Antunes, F.V.; Sérgio, Edmundo R.; Vasco-Olmo, J.M.; Díaz, F.A.; Neto, D. M.In the context of fatigue crack growth (FCG), the validation of FEM predictions with experimental results has been made in terms of crack closure and da/dN. The objective here is to compare the prediction of the displacement field, which is the primary output of FEM, with experimental results obtained with Digital Image Correlation (DIC). The qualitative comparison indicates that DIC and FEM results are very si...
Effect of crack flank holes on fatigue crack growth
Neto, D. M.; Cavaleiro, N.; Sérgio, Edmundo R.; Jesus, J. S. de; Camacho-Reyes, A.; Antunes, F.V.The effect of drilling two symmetric holes along the crack flanks on the fatigue crack growth (FCG) rate was evaluated numerically. The FCG increases (decreases) when the crack tip is behind (ahead) the holes. This behaviour is enlarged both by increasing the diameter of the holes and by reducing the distance between them. This is consequence of the geometrical effect, which modifies the plastic zone size. Expe...
Effect of variable amplitude block loading on fatigue crack growth
Neto, D. M.; Borges, M. F.; Silva, J. M.; Antunes, F. V.The objective is to study the effect of load blocks on fatigue crack propagation. To carry out this study, the finite element program DD3IMP will be used, with the fatigue crack propagation being controlled by the value of the plastic deformation at the end of the crack. The material used was the Ti6Al4V alloy obtained by the selective laser fusion manufacturing process. Regarding the studied load patterns, two...
Influence of the anisotropic behavior on equibiaxial paths
Salles, F. F.; Oliveira, M. C.; Neto, D. M.; Alves, J. L.; Menezes, L. F.; Fernandes, J. V.Marciniak and Nakajima tests are commonly used in building FLD's, since they allow covering all regions from uniaxial to almost equibiaxial strain paths. In this work, the deviation from equibiaxial strain paths is analyzed as function of the material anisotropic behavior. The numerical results show that material with r0 = r90 present equibiaxial stress and strain paths, while for the ones with r0 ≠ r90 the pat...
Assessing the accuracy of different remapping methods in adaptive mesh refinement
Marques, B. M.; Neto, D. M.; Alves, J. L.Additive manufacturing of metals has attracted much attention over the last years, promoting the development of several computational models for numerical simulation of the laser powder bed fusion (LPBF) process. Nevertheless, the finite element analysis of the LPBF process requires a large computational time. Thus, adaptive mesh refinement strategies are commonly adopted to reduce computational cost, which req...
Influence of specimen orientation on fatigue crack growth in 7050-T7451 and 205...
Jesus, J. S.; Antunes, F. V.; Prates, P.; Branco, R.; Antunes, P. V.; Borrego, L. P.; Neto, D. M.The effect of L-T and S-T orientations on FCGR is here in studied in 7050-T7451 and 2050-T8 aluminum alloys. The Low-cycle fatigue tests and hardness measurements have shown that specimen orientation has a minor effect on material plastic hardening. Lower FCG rates are obtained for both materials in the L-T orientation, which can be associated to the resistance at grain boundaries. The larger cyclic plastic zon...
Effect of remaining ligament on fatigue crack growth
Jesus, Joel; Neto, D. M.; Fernandes, R. F.; Borges, M. F.; Antunes, F. V.; Sérgio, E. R.Fatigue crack growth (FCG) has been studied assuming that Keff is the crack driving force. However, the effect of crack ligament on FCG rate is not clear. Experimental-numerical work was developed in the 18Ni300 maraging steel considering different load blocks with the same initial K. No effect of crack ligament was observed experimentally, which was explained by the inexistence of crack closure effects. In t...
Single overloads FCG modeling considering damage accumulation
Sérgio, E. R.; Borges, M. F. M.; Neto, D. M.; Antunes, F. V.; Pais, J. P.In this study, Fatigue Crack Growth (FCG) in a CT specimen, submitted to single overloads, is predicted by a node release numerical model, which considers the plastic strain to be the main FCG driving force. The Gauss-Tvergaard-Needleman (GTN) damage model was implemented to account for the, inevitable, growth and nucleation of microvoids in the occurrence of high levels of plastic strain. Crack closure shown t...
Study on the influence of the strain rate sensitivity on the springback of the ...
Neto, D. M.; Oliveira, M. C.; Alves, J. L.; Menezes, L. F.Warm forming processes have been successfully applied to overcome some important drawbacks of the aluminium alloys, such as poor formability and large springback. The virtual try-out of this type of processes requires the accurate prediction of springback. The process conditions considered in this work are the ones established for the benchmark 3 - Springback of an Al-Mg alloy in warm forming conditions, propos...