The dialog controls the mode combination technique for the calculation of the maximum response in a respose spectrum analysis.
To display this dialog, in the Simulation study tree, right-click the study's icon and select Properties. Click Response Spectrum Options.
Mode Combination Method
Select one from the available methods.
Square Root Sum of Squares (SRSS)
Absolute Sum
Complete Quadratic Combination (CQC)
Naval Research Laboratory
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For more information, see Mode Combination Techniques. |
| Cluster Factor |
If the ratio of the modal period spacing over the lowest period is larger than the cluster factor (
 ), the program uses the SRSS method (instead of the Absolute Sum) for these particular modes to calculate the maximum response. |
| Use material damping ratio from material definition |
The modal damping coefficients are calculated from the material damping ratio you specify in the Properties tab of the Material dialog. The modal damping coefficients are used for the CQC method only. |
Curve Interpolation
Select the interpolation scheme to calculate spectral values from the response spectrum curve.
| Logarithmic |
The program first converts the input response spectrum curve to a Log-Log curve. Calculates the response values for the frequencies of interest with linear interpolation. Converts the response values back to the linear scale. |
| Linear |
The program uses a second degree polynomial for curve-fitting between two consecutive response spectrum points. There is no conversion to a Log-Log scale. |