3D Connexion Version 6.6

*MASS DIFFUSION

13.3 *MASS DIFFUSION: Transientor steady-state uncoupled mass diffusion analysis.

This option is used to controluncoupled transient or steady-state mass diffusion analysis.

Product: ABAQUS/Standard

Type: History data

Level: Step

Reference:

•“Mass diffusion analysis,” Section6.8.1 of the ABAQUS Analysis User ’sManual

Optional parameters:

DCMAX

Set this parameter equal to the maximum normalized concentration change to be allowed in

an increment. ABAQUS/Standard will restrict the time step to ensure that this value will not

be exceeded at any node (except nodes with boundary conditions) during any increment of the

analysis. If the DCMAX parameter is omitted, ﬁxed time increments will be used.

END

Set END=PERIOD (default) to analyze the entire time period speciﬁed on the data line. Set

END=SS to end the analysis when steady state is reached.

STEADY STATE

Include this parameter to choose steady-state analysis. Transient analysis is assumed if this

parameter is omitted.

Data line to deﬁne time stepping in a mass diffusion analysis:

First (and only) line:

1. Timestep. If automatic stepping is used, this value should be a reasonable suggestion for the

initial step and will be adjusted as necessary.

2. Time period. If END=SS is chosen, the step ends when steady state is reached or after this

time period, whichever occurs ﬁrst.

3. Minimum time increment allowed. If ABAQUS/Standard ﬁnds it needs a smaller time

increment than this value, theanalysis is terminated. Ifno value is given, ABAQUS/Standard

sets the minimum increment to the minimum of0.8 tim es the suggested initial time step (the

ﬁrst data item on this line) and 10−5 times the time period (the se cond data item on this line).

13.3–1

ABAQUS Version 6.1 Module: ID:

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