lcpt
commented
5 years ago Hi. In test_deflection_prestressed_beam_02.py you must update the state of the element after changing the value of the prestress (see line 159).
This is automatically done when the element is put in a mesh (in line 124 ) or if you modify the material state and you perform a non-linear analysis which will detect the lack of equilibrium due to the modification in the material stress.
I'll take a look to the third test as soon as I can.
anaiortega
Hi,
I have a problem with a test I'm performing to check deflections in prestressed beams. The question is, at some point, I must impose a reduction of prestressing in a beam (from 6800 to 4500 kN/m2). I've tried two methods: 1) change the prestress in the material of each element of the cable, 2) impose an equivalent strain in the elements.
In repository work_in_progress there are three simple models to reproduce the issue:
test_deflection_prestressed_beam_01.- The initial stress in prestressing steel is set to 4500 kN/m2 -> The model outputs the right results (uz=40 mm & N=4500 kN) that match those from a direct calculation, but only because the final tension is directly assigned to the material in its definition statement.
test_deflection_prestressed_beam_02.- I set initial stress in prestressing steel = 6800 kN/m2. Before calculating I set a prestress of 4500 kN/m2 to the material of each element (lines 157-158). Results: uz=60.5 mm (as if prestress = 6800 kN/m2), N=4500 kN
test_deflection_prestressed_beam_03.- I set initial stress in prestressing steel = 6800 kN/m2. Before calculating I try to impose a strain in order to reduce the stress from 6800 kN/m2 to 4500 kN/m2 (lines 157-162) results: idem to case 1. The following error arises: ElementBodyLoad::applyLoad; el number of pointers no coincide con el de identifiers.
Any idea how to tackle it?