proksi83
Materials
- Jan 3, 2013
- 1
Hello folks,
I would like to simulate the induced volume changes upon Li insertion into Si nanowires by ABAQUS. When Li diffuses into these nanowires, upon fully lithiation of Si about 280% volumetric change occurs. These huge volume swings induce large stresses and strains in nanowire structure. Then Si nanowires undergo severe structural degradation and also disintegration. Now we are looking for a way to simulate these stresses and see how they distribute inside a nanowire and how much they are. To do so, I think we need to have either a coupled mass diffusion-displacement analysis or an uncoupled diffusion-displacement one in which the concentration would be the predefined value at nodes. This work has been done before by others and they have used coupled temperature-displacement procedure in ABAQUS/Standard. That is, the normalized concentration is surrogated by temperature and the lithiation expansion coefficient βij is equivalently treated as the thermal expansion coefficient. The user material subroutine for heat transfer (UMATHT) is programmed to interface with ABAQUS to update diffusivities based on the current Li concentration (i.e., temperature). They don't mention anything about their thermal models as how they simulate Li diffusion into the wires and how come they can correlate it to temperature.
Any comments or thoughts would be appreciated.
Thanks so much,
Proksi83
I would like to simulate the induced volume changes upon Li insertion into Si nanowires by ABAQUS. When Li diffuses into these nanowires, upon fully lithiation of Si about 280% volumetric change occurs. These huge volume swings induce large stresses and strains in nanowire structure. Then Si nanowires undergo severe structural degradation and also disintegration. Now we are looking for a way to simulate these stresses and see how they distribute inside a nanowire and how much they are. To do so, I think we need to have either a coupled mass diffusion-displacement analysis or an uncoupled diffusion-displacement one in which the concentration would be the predefined value at nodes. This work has been done before by others and they have used coupled temperature-displacement procedure in ABAQUS/Standard. That is, the normalized concentration is surrogated by temperature and the lithiation expansion coefficient βij is equivalently treated as the thermal expansion coefficient. The user material subroutine for heat transfer (UMATHT) is programmed to interface with ABAQUS to update diffusivities based on the current Li concentration (i.e., temperature). They don't mention anything about their thermal models as how they simulate Li diffusion into the wires and how come they can correlate it to temperature.
Any comments or thoughts would be appreciated.
Thanks so much,
Proksi83