ABAQUS Volume II: I–Z - Manual (Page 477)

*STEP
18.36 *STEP: Begin a step.
This option is used to begin each step definition. It must be followed by a procedure definition option.
Products: ABAQUS/Standard ABAQUS/Explicit
Type: History data
Level: Model
Beginning a step in an ABAQUS/Standard analysis
References:
•
“Procedures: overview,” Section 6.1.1 of the ABAQUS Analysis User’s Manual
•
“Convergence criteria for nonlinear problems,” Section 7.2.3 of the ABAQUS Analysis User’s Manual
•
“Design sensitivity analysis,” Section 14.1.1 of the ABAQUS Analysis User’s Manual
•
*END STEP
Optional parameters:
AMPLITUDE
This parameter defines the default amplitude variation for loading magnitudes during the step.
Set AMPLITUDE=STEP if the load is to be applied instantaneously at the start of the step and
remain constant throughout the step.
Set AMPLITUDE=RAMP if the load magnitude is to vary linearly over the step, from the
value at the end of the previous step (or zero, at the start of the analysis) to the value given on the
loading option.
If this parameter is omitted, the default amplitude choice depends on the procedure chosen,
as shown in “Procedures: overview,” Section 6.1.1 of the ABAQUS Analysis User’s Manual. The
default amplitude variation can be overwritten for individual loadings by using the AMPLITUDE
parameter on the loading options (“Amplitude curves,” Section 27.1.2 of the ABAQUS Analysis
User’s Manual).
This parameter is rarely needed, and changing the defaults may cause problems. For
example, the automatic load incrementation scheme in procedures without a real time scale (such
as the *STATIC option) applies the loads gradually by incrementing the normalized time scale.
The use of AMPLITUDE=STEP specifies that the entire load will be applied immediately, so
ABAQUS/Standard may not be able to choose suitable small increments if the loading causes
strongly nonlinear response.
18.36–1
ABAQUS Version 6.1 Module: ID:
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