61 documents found, page 1 of 7
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...
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...
Influence of the orthotropic behaviour on defects prediction in cup drawing, re...
Oliveira, M. C.; Neto, D. M.; Alves, J. L.; Menezes, L. F.Finite elements analysis is commonly used in the cans tool design since it allows predicting different sheet metal defects and instabilities that significantly affect the efficient production of beverage cans. These defects include caring, due to the material orthotropic behaviour, thinning and fracture. The numerical prediction of these kind of defects is more complex when different combinations of strain path...
Experimental and numerical analysis of the heat generated by plastic deformatio...
Neto, D. M.; Simoes, V. M.; Oliveira, M. C.; Alves, J. L.; Laurent, H.; Oudriss, A.; Menezes, L. F.This study evaluates the temperature variation observed in quasi-static uniaxial tensile tests, due to the heat generated by plastic deformation. The AA6016-T4 aluminium alloy was the material selected, considering different values of crosshead velocity (from 0.01 mm/s up to 1 mm/s). The temperature variation was also evaluated during the stress relaxation test. A finite element model of the uniaxial tensile te...
Study on the influence of the yield surface shape in the hole expansion test
Oliveira, M. C.; Neto, D. M.; Alves, J. L.; Menezes, L. F.The hole expansion test has become popular since it allows to study the formability of metallic sheets, in particular the onset of necking in stretch flanging areas. The accurate prediction of strain localization and consequent fracture requires a proper description of the plastic behavior, particularly the anisotropic yield function. In the context of strain localization prediction, the yield criterion adopted...
Heat generation when forming AHSS: experimental and numerical analysis of tensi...
Neto, D. M.; Barros, J. R.; Oliveira, M. C.; Antunes, P. V.; Ramalho, A.; Amaral, R. L.; Santos, A. D.; Alves, J. L.; Menezes, L. F.The increasing use of advanced high-strength steels in sheet metal forming processes requires improved knowledge concerning the thermal and contact conditions. This study presents the experimental and numerical analysis of tensile and draw-bead tests, considering a dual phase steel DP780. The temperature evolution was measured in both tests using an infrared thermal camera. The presented finite element model co...
Influence of the characteristics of the 3D FE mesh on the evolution of variable...
Brito, J. P.; Oliveira, M. C.; Neto, D. M.; Alves, J. L.; Menezes, L. F.It is well-established that the ductile fracture in metallic materials is a highly stress state dependent physical process. Past research has focused on the development of numerical tools that describe the mechanisms of the ductile damage. In this framework, the computed damage distribution is affected by the accuracy in the description of the stress state history, aside from the choice of the damage model. Thu...
Study on the influence of orthotropy and tension–compression asymmetry of metal...
Barros, P. D.; Neto, D. M.; Alves, J. L.; Oliveira, M. C.; Menezes, L. F.Most yield criteria possess a point-symmetry with respect to its center, meaning that a stress state and its reverse state have the same absolute value. However, this can be an unrealistic approximation, even for cubic metals (both face-centered cubic and body center cubic)), which can present a small asymmetry between the yield stress in tension and compression, i.e. a strength differential (SD) effect. This w...
Temperature analysis during the drawing of an aluminum cylindrical cup
Simões, V. M.; Neto, D. M.; Oliveira, M. C.; Alves, J. L.; Laurent, H.; Menezes, L. F.Both the plastic deformation and the friction forces generate heat in sheet metal forming processes. This yields a temperature rise on the blank and tools, which is mainly dictated by the blank properties and the press speed. Although modest values of temperature rise yield negligible changes in the mechanical behavior of metals, the lubricant properties are rather influenced by the temperature. Thus, the deep ...
Incremental volumetric and Dual Kriging remapping methods
Miguel, C.; Neto, D. M.; Oliveira, M. C.; Alves, J. L.; Menezes, L. F.The transfer of variables between distinct spatial domains is a problem shared by many research fields. Among other applications, it may be required for visualization purposes or for intermediate analysis of a process. In any case, two important factors must be considered: accuracy and computational performance. The accuracy becomes more important when the results have an impact on the subsequent stages of the ...