Learning Forum

[Inan]

Hi there. So for my university project I have designed a suspension bridge on ANSYS workshop however I am encountering abnormally large displacements and and other results on mechanical. This question is a follow up from a previous question which I asked in the forum below.

Hi there. I'm a final year student in my civil engineering degree. For my final project, I decided to do some finite element analysis for a suspension bridge. I chose to model the Humber suspension bridge using Ansys workshop design modeler. I'm encountering two problems with my model mentioned below.

1) I modelled my suspension bridge to scale using some measurements I got from a few reports. The bridge is around 2200m long. In mechanical, the forces I applied to my bridge is gravity, a pressure and some fixed supports at the end of the main cable, end of deck and bottom of the tower. When I try to solve my bridge, I'm achieving maximum displacements of around 700.18m. This I know for sure is not realistic and I cant seem to find a solution to this problem.

2) My second problem is currently my whole bridge except for my deck is modelled with BEAM188 elements and the deck is modelled with a SHELL181 element. I want to adjust hangers and main cable to be LINK10 elements. I cant seem to figure out how to do this.

https://us.v-cdn.net/6032193/uploads/0VTQW03CV41Z/image.png

Some guidance with these problems would be greatly appreciated. Below I have attached my project file if you would like to look into the model. Thank you very much in advance.

https://drive.google.com/drive/folders/1dLUYlYOD0lg5QA7rG98nwsN2E_WTwijT?usp=sharing

[Ashish Khemka]

nnAnsys employees cannot download the model. But it looks that the solution did not converge. Can you please check what was the deformation for the last converged substep?.This may give you some idea of how the deformation is for a converged substep.nnRegards,nAshish Khemkan

[Erik Kostson]

Also try to have one element per cable structure, because it looks like the issue is with the cables. So one element per cable.

[Inan]

nThank you very much for the reply, and apologies for the late reply.nSo I followed your suggestion and I checked what was the deformations at the last converged substep. My initial maximum displacement on my working model was 700.18m. After turning on large deflections, turning off small sliding, and checking my deformations at my last converged substep, the maximum displacement has now reduced to 18.984m. This is a large improvement, however my model is not working correctly after applying those changes. Also, 18.984m is still a large value of deflection for a suspension bridge. I'm new to Ansys so I'm not really sure what is wrong with my model. nI would greatly appreciate any suggestions you can provide in order to fix this model. Below I have attached this newly updated version of the model in case it proves useful at identifying a fix to my problem. nThank you very much for your time.nRegards,nInann

[Inan]

nThank you for the reply, and apologies for the late reply.nI believe the answer to your question is yes. All the cables are modelled individually and they are modelled using BEAM188 elements. Everything in the model other than the deck is modelled with BEAM188 elements whereas the deck is modelled using a SHELL181 element. Not sure why my structure stopped working after apply those changes.nThank you very much.nRegards,nInann