Opensees drag load

This test analyses the dynamic response of a cantilever beam subjected to drag loads applied at the middle of the beam. Results produced by OpenSees 3.7.1 are used to benchmark Ashes.

This test uses a simple cantilever beam modeled with the Tubular tower only template.

The model consists of a uniform circular hollow cross section with a diameter and a thickness , and a length of 40 m. The beam is split into 2 elements.

A load is applied at the mid-position of the beam. The load is equivalent to a drag load on the structure for regular waves of 5 m height and 10 s period. This is meant to represent the 5-MW monopile in waves.

All other loads (gravity and aerodynamics) are disabled.

A stiffness proportional damping is applied set at 5% for the first eigenperiod of the system T = 0.305 s.

The solver is set to linear.

The same setup was simulated with OpenSees 3.7.1. The OpenSees simulation can be reproduced downlading the tcl input file and the load file.

We compare the shear forces and moments of the beam as well as the node displacements.

A simulation of 20 seconds is run. The results from Ashes and OpenSees are visually compared. When that comparison is satisfactory, as in the figures shown below, a regression test is created with the corresponding results. As long as the regresison test passes, the visual comparison shown below is valid.

The comparison between Ashes and OpenSees can be viewed on this link:
https://www.simis.io/downloads/open/benchmarks/current/Opensees drag load.pdf