Hello mariog:
After further review I have a couple questions pertaining to the Duhamel's Integral (attached) that CAESAR II uses to create the DLF spectrum.

First off, I am assuming that the equation only uses the force vs time curve that is provided by the user. The equation calculates the dynamic displacement of an arbitrary system based on the force vs time curve.

Based on those assumptions I have a few questions:

1) Does Duhamel's Integral consider the piping system?

2) How is the static displacement calculated that is used to create the DLF? Is it calculated using Duhamel's Integral?

3) What is the 1/M value in Duhamel's Integral?

Thanks,