RT Journal Article
T1 Void growth in ductile materials with realistic porous microstructures
A1 Ambikadevi Rajasekharan Nair, Vishnu
A1 Vadillo Martin, Guadalupe
A1 Rodríguez-Martínez, José A.
A1 Rodriguez Martinez, Guillermo
AB In this paper, we have investigated void growth in von Mises materials which contain realistic porous microstructures. For that purpose, we have performed finite element calculations of cubic unit-cells which are subjected to periodic boundary conditions and include porosity distributions representative of three additively manufactured metals. The initial void volume fraction in the calculations varies between 0.00564% and 1.75%, the number of actual voids between 14 and 5715, and the pores size from 2.3mum to 110mum. Several tests with different void sizes and positions have been generated for each of the three porous microstructures considered, and for each test we have performed several realizations with different spatial arrangement of the voids. The simulations have been carried out with random spatial distributions of pores and with clusters of the same size and different void densities. The macroscopic stress state in the unit-cell is controlled by prescribing constant triaxiality and Lode parameter throughout the loading. Calculations performed exchanging the loading directions for a given distribution of void sizes and positions have shown that the porous microstructure makes the macroscopic strain softening of the unit-cell (slightly) anisotropic. Moreover, the results obtained with the realistic porous microstructures have been compared with unit-cell calculations having an equivalent single central pore, and with calculations in which the material behavior is modeled with Gurson plasticity. It has been shown that both initial void volume fraction and spatial and size distribution of voids affect the macroscopic response of the porous aggregate and the void volume fraction evolution. Moreover, the calculations with random spatial distribution of voids have brought out that different tests of the same microstructure carry significant variations to the effective behavior of the porous aggregate, and that the interaction between neighboring pores dictates the volume evolution of individual voids, especially at higher macroscopic triaxiality. The calculations with clusters have shown that pores clustering promotes localization/coalescence due to increased interaction between the voids, which results in an increased growth rate of voids in clusters with large number of pores. Moreover, the results for the evolution of the distribution of plastic strains in the unit-cell have provided quantitative indications of the role of porous microstructure on the development of heterogeneous plastic strain fields which promote macroscopic strain softening. Namely, the accelerated growth rate of the plastic strains near the voids which indicates the onset of localization/coalescence has been shown to occur earlier as the number of voids in the microstructure increases.
PB Elsevier
SN 0749-6419
YR 2023
FD 2023-08-01
LK https://hdl.handle.net/10016/39187
UL https://hdl.handle.net/10016/39187
LA eng
NO The research leading to these results has received funding from the European Research Council (ERC) under the European Union’sHorizon 2020 research and innovation programme. Project PURPOSE, grant agreement 758056. G. Vadillo acknowledges the financial support provided by the Spanish Ministry of Science and Innovation under the programme Proyectos I+D Excelencia 2017. Project APPLIED, DPI2017-88608-P. This work has been supported by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M24), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation).
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RD 30 jun. 2024