Lido,

System damping delays response - the maximum response at a node occurs after the maximum applied force or applied displacement. This was Rich's focus in his response to you - relating input to response.

Your topic is CAESAR II dynamic input (not response) where we are interested in establishing a relationship between two or more harmonic force vectors. This phase angle establishes that relationship.

I do not know which version of CAESAR II you are using - pages 709 & 719 of the current User Guide have nothing to do with phase angles. Looking at page 722 of the User Guide (CAESAR II 2019 / Version 11), I see A*cos(wt+phi). Phase angle also appears on pages 725 & 728. These equations show A*cos(wt-phi).

I will agree that there is no reason for there to be both a (wt+phi) and a (wt-phi). The first reference (+phi, page 722) is used in the definition of the applied harmonic frequencies. But here, phi is not used - just the frequencies (w) are collected. The other two occurrences are correct (-phi, pages 725 & 728).

I will ask that the User Guide be updated to remove that (+phi) from page 722.