no reaction forces/moment on dynamic response 3d analysis

sofien_73

I everyone,
send you a model steel framework with modal spectral analysis which produce no reaction forces and moment. but it's still works for displacements/internal forces and moments.

Victor, have seen this kind of problems before, the model is heavy I may have done some mistakes with dynamic analysis?
Regards

Victor

Unfortunately reaction forces (and external forces) aren't available with dynamic response with the internal solver or CCX, but only with OpenRadioss. OpenRadioss via Mecway doesn't currently have line pressure, pinned support, or constraint equations so if you did use that, you'd need to convert those to force, displacement, and flexible joint on beam respectively.

You could use the beam internal forces and moments near the supports as reaction forces and moments. Or is it that you want reaction forces to validate these?

sofien_73

Thanks Victor, in that case I Will use beam forces at the edges near external bounding conditions. All this issues with dynamic reponse 3d analyses should be solved for internal solver on the next versions of Mecway (using beam releases, extract reaction forces and moment,..).
Regards

disla

HI,

Assuming the are no external forces on the bases, aren't beam forces at the edges near external bounding conditions same as reactions?
Axial could be debatable as it may not be strictly vertical reaction force if the columns are hinged but shear should ¿isn't it?.

What I also see is that Sum doesn't work (Shows empty) on Axial or Shear for a set of nodes (Bases)

sofien_73

Agree with disla there's something ugly on my model here some other example:
I have no axial forces and bending moment (strong axis) on the column n°19 and 23 which is impossible here below some table extract with dynamic analysis case 1 vs static analysis case 1 (the same) but with beam release on bracings where as constraint equations (which don't works I think) on the dynamic response 3d model






As Victor said, we're not able yet to perform modal spectral dynamic studies with dynamic response 3d.

As a steelworks expert it is not an option most of the steelworks design I've previously performed involved seismic hasard with modal spectral analysis. In my opinion it's a critical issue and it have to be fixed on the very next version of MECWAY