ProductsAbaqus/StandardAbaqus/CAE
TypeHistory data
LevelStep
Abaqus/CAEStep module
Optional parameters
 COMP

Set COMP=ALGEBRAIC to sum the directional excitation components algebraically. If
this parameter is used, the directional excitation components are summed first,
followed by the modal summation.
Set COMP=SRSS (default) to use the square root of the sum of the squares. If
this parameter is used, the modal summation is performed first, followed by the
summation of the directional excitation components.
Set COMP=R40 to use the 40% rule as recommended by the
ASCE 4–98 Guide that assumes that for the
maximum response from one component, the responses from the other two
components are 40% of their maximum value.
Set COMP=R30 to use the 30% rule. This rule assumes that for the maximum
response from one component, the responses from the other two components are
30% of their maximum value. It follows the expressions for the 40% rule as
described in the ASCE 4–98 Guide.
 RIGID RESPONSE

Set RIGID RESPONSE=GUPTA to use the Gupta method for modal summation of periodic and
rigid regions in the response spectrum. If this parameter is omitted, no rigid
response is included.
Set RIGID RESPONSE=LINDLEYYOW to use the LindleyYow method for modal summation of periodic
and rigid regions in the response spectrum. If this parameter is omitted, no
rigid response is included.
 SUM

Set SUM=ABS (default) to sum the absolute values of the responses in each
natural mode.
Set SUM=CQC to use the complete quadratic combination method to sum the
responses in each natural mode.
Set SUM=DSC to use the double sum combination. This method is the first
attempt to evaluate modal correlation based on random vibration theory. It
utilizes the time duration ${t}_{D}$
of strong earthquake motion.
Set SUM=GRP to use the grouping method as described in
USNRC Regulatory Guide 1.92, February 1976.
Set SUM=NRL to use the Naval Research Laboratory method.
Set SUM=SRSS to use the square root of the sum of squares summation.
Set SUM=TENP to use the Ten Percent Method.
Data lines
for a response spectrum analysis
 First line

Name of the response spectrum to be used.

Xdirection cosine of this direction.

Ydirection cosine of this direction.

Zdirection cosine of this direction.

Factor multiplying the magnitudes in the response spectrum. Default is 1.0.

Time duration of the dynamic event, from which this spectrum was created.
This value is required for the DSC modal summation rule.

Zero period acceleration or cutofffrequency value in cycles per time.
Default is 33 Hz. This value is used for the LindleyYow rigid response method.
If the Gupta rigid response method is used, this is the F1
frequency value in cycles/time.

For the Gupta rigid response method, enter the F2
frequency value in cycles/time.
 Second line (optional)


Name of the response spectrum to be used in the second direction.

Xdirection cosine of this direction. This direction
must be at a right angle to the direction defined above.

Ydirection cosine of this direction. This direction
must be at a right angle to the direction defined above.

Zdirection cosine of this direction. This direction
must be at a right angle to the direction defined above.

Factor multiplying the magnitudes in the response spectrum. Default is 1.0.

Time duration of the dynamic event, from which this spectrum was created.
This value is required for the DSC modal summation rule.

Zero period acceleration or cutofffrequency value in cycles per time.
Default is 33 Hz. This value is used for the LindleyYow rigid response method.
If the Gupta rigid response method is used, this is the F1
frequency value in cycles/time.

For the Gupta rigid response method, enter the F2
frequency value in cycles/time.
 Third line (optional)


Name of the response spectrum to be used in the third direction.

Xdirection cosine of this direction. This direction
must be at right angles to the two directions defined above.

Ydirection cosine of this direction. This direction
must be at right angles to the two directions defined above.

Zdirection cosine of this direction. This direction
must be at right angles to the two directions defined above.

Factor multiplying the magnitudes in the response spectrum. Default is 1.0.

Time duration of the dynamic event from which this spectrum was created.
This value is required for the DSC modal summation rule.

Zero period acceleration or cutofffrequency value in cycles per time.
Default is 33 Hz. This value is used for the LindleyYow rigid response method.
If the Gupta rigid response method is used, this is the F1
frequency value in cycles/time.

For the Gupta rigid response method, enter the F2
frequency value in cycles/time.