how to add gravity body force, b_i, into biot.py
Hi all,
I would like to add gravity body force, b_i, into biot.py: http://sfepy.org/docdevel/examples/biot/biot.html I could find any examples.
The body force, b_i, in balance equation can be expressed by
(\sigma_{ij}  p \delta_{ij}),j + \rho b_i = 0
where \sigma_{ij} is stress, p is pore pressure and \rho is the density of solid phase. \delta_{ij} is Kronecker delta.
Should I add a new term from scratch?
Thanks in advance.
ouyang
Hi!
On 07/03/2014 12:47 PM, Ouyang wrote:
Hi all,
I would like to add gravity body force, b_i, into biot.py: http://sfepy.org/docdevel/examples/biot/biot.html I could find any examples.
The body force, b_i, in balance equation can be expressed by
(\sigma_{ij}  p \delta_{ij}),j + \rho b_i = 0
where \sigma_{ij} is stress, p is pore pressure and \rho is the density of solid phase. \delta_{ij} is Kronecker delta.
Should I add a new term from scratch?
No need for that. You can use dw_volume_lvf term for this purpose, with a vector material parameter (shape (3, 1) in 3D) for the body forces b_i, something like that:
materials = { 'gravity' : ({'b' : [[1], [1], [1]]},), }
and in equations: dw_volume_lvf.i.Omega(gravity.b, v) (v is a test function).
It is used in diffusion/poisson_iga.py and diffusion/poisson_parametric_study.py examples in scalar context.
r.
Thanks for your quick reply. Let me try it.
ouyang
On Thursday, July 3, 2014 7:06:49 PM UTC+8, Robert Cimrman wrote:
Hi!
On 07/03/2014 12:47 PM, Ouyang wrote:
Hi all,
I would like to add gravity body force, b_i, into biot.py: http://sfepy.org/docdevel/examples/biot/biot.html I could find any examples.
The body force, b_i, in balance equation can be expressed by
(\sigma_{ij}  p \delta_{ij}),j + \rho b_i = 0
where \sigma_{ij} is stress, p is pore pressure and \rho is the density of solid phase. \delta_{ij} is Kronecker delta.
Should I add a new term from scratch?
No need for that. You can use dw_volume_lvf term for this purpose, with a vector material parameter (shape (3, 1) in 3D) for the body forces b_i, something like that:
materials = { 'gravity' : ({'b' : [[1], [1], [1]]},), }
and in equations: dw_volume_lvf.i.Omega(gravity.b, v) (v is a test function).
It is used in diffusion/poisson_iga.py and diffusion/poisson_parametric_study.py examples in scalar context.
r.
participants (2)

Ouyang

Robert Cimrman