{"id":355041,"date":"2024-03-04T08:14:54","date_gmt":"2024-03-04T08:14:54","guid":{"rendered":"\/forum\/forums\/topic\/different-stress-strain-diagram-of-rc-beam\/"},"modified":"2024-03-04T08:14:54","modified_gmt":"2024-03-04T08:14:54","slug":"different-stress-strain-diagram-of-rc-beam","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/different-stress-strain-diagram-of-rc-beam\/","title":{"rendered":"Different Stress-Strain Diagram of RC Beam"},"content":{"rendered":"

Hi everyone! I am modelling a Reinforced Concrete Beam subjected to a four point bending test. The nonlinear solution is already converging and some of the values are relatively close to my reference. Here are my concerns:<\/p>\n

(1) <\/p>\n

However, the force-deflection curve \/ stress-strain diagram shows a sudden decrease after reaching the yield stress and then gradually increases. It’s not supposed to show sudden drops in strength after yielding, I expect it to increase continuously. Can someone suggest how I can fix this? <\/p>\n

 <\/p>\n

I used Menetrey Willam model for the concrete with the following parameters<\/p>\n

<\/p>\n

I am also unsure if my boundary conditions are correct. I used an edge as a pin support (UX=UY=UZ= 0 and Rx = FREE RY=RZ=0) while the loading is a face with remote displacement (UX=UZ=0, UY = -7, Rx = FREE, RY = RZ = 0). I put a finer mesh at these conditions because there is too much strain in one element if I let it be the same as the other mesh.<\/p>\n

<\/p>\n

I have also checked the stress-strain diagram of the rebars and it is correct. Do you have suggestions on how I can stop the sudden decrease after yielding?<\/p>\n

 <\/p>\n

(2) I noticed  that when I change the mesh method and even the mesh size to smaller, it does not converge anymore. I expected that since my model converged, decreasing my mesh would yield more accurate results. Is this normal? How else can I do a mesh convergence test?<\/p>\n

Any suggestions would be appreciated. Thank you!!<\/p>\n","protected":false},"template":"","class_list":["post-355041","topic","type-topic","status-closed","hentry","topic-tag-3d-meshing","topic-tag-concrete-non-linear","topic-tag-menetrey-william","topic-tag-meshing","topic-tag-reinforced-concrete","topic-tag-Stress-strainanalysis-1","topic-tag-stress-strain-curve","topic-tag-thesis-help-1","topic-tag-three-point-bending-test"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t