/ALE/SOLVER/FINT
Block Format Keyword This option defines the numerical method for internal force integration. This is relevant only for brick element and ALE legacy solver (momentum equation solved with FEM).
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
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/ALE/SOLVER/FINT | |||||||||
Iform |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
Iform | Integration method
(internal force for brick elements) flag.
(Real) |
Comments
- Momentum equation has local form:
(1) ∂ρu∂t+div(ρuu)=div(σ)+ρgIform is a flag defining the numerical method to compute div(σ) when integrated over the cell with legacy solver (nodal velocities).- Iform=1
- Fint=∫Ωdiv(σ)dV
- Iform=2
- Fint=-∫∂ΩpdS+∫Ωdiv(σ)dV
- Iform=3
- Fint=∫∂Ω(-pI+σdev)dS
For volume integration, shape functions are used to compute at node, N:(2) FiNint=σik∂ΦN∂xk|0|Ω|Where, i=1,3
The value ∂ΦN∂xk|0 is taken at the integration point. It is assumed that:(3) ∂ΦN1∂xj=−∂ΦN7∂xj ; ∂ΦN2∂xj=−∂ΦN8∂xj ; ∂ΦN3∂xj=−∂ΦN5∂xj ; ∂ΦN4∂xj=−∂ΦN6∂xjThis assumption is exact for parallelepipedic shape only, which is why the new default value method is set to surface integration (Iform=3).