Need Help Simulating Pole Vault Through FEA in ANSYS
Need Help Simulating Pole Vault Through FEA in ANSYS
(OP)
Hi, I am stressing over a class project I have to do. I got myself way in over my head with this one. I am trying to simulate pole vaulting through the use of FEA with ANSYS. My professor is new to the topic and has not been able to help me much. All I have to go off of, that I consider useful, is a research paper "SIMULATION OF ‘SMART’ POLE VAULTING" by Mats Ekevad and Bengt Lundberg. This paper is actually really cool because the authors have done exactly what I am trying to do. However, because I am new to this, I am left with very little to go off of in terms of creating the actual models and setting the proper loads and constraints. I was really hoping someone here has a better understanding than I do and could help me out. If there are tutorials that I can use to piece my project together or if someone has done anything similar. I am really stuck and have exhausted just about all other resources that I can think of.
The overall goal of my project is to accurately simulate pole vault as best I can in order to determine the optimal pole length for any given vaulter.
The gist of the paper:
The pole is considered to be a one-dimensional beam with transverse shear, large displacements, large strains, and rotary as well as transverse inertia. Pin joints connect the bottom end of the pole to the ground and the top end of the pole to the vaulter. The pole is modeled using 20 equally long two-node beam elements. The initial velocity of the pole is taken to be the same as that of the vaulter except at the box end which is simply supported. It has a variably thin-walled pip cross-section, with three layers of linearly elastic materials (glass fibre).
The vaulter model consists of 6 segments with five pin joints. The two legs of the vaulter are modeled as a single, two segment leg. The same is true for the two arms.
Here's an image of the initial stance of the pole vaulter

UPDATE: By placing a point mass located at the vaulter's center of gravity I was able to accurately mimic the pole's motion
Here's an image of essentially the goal of what I want my simulation to look it.

If you have absolutely no idea what pole vaulting is. Here's a quick link to give you a good idea on what pole vault entails from an engineering perspective.
Link
At this point in time I have close to nothing completed that gets me closer to my goal. I have modeled the geometry of the pole and the vaulter using simple line bodies in ANSYS DesignModeler. Instead of trying to create the three elastic layers of the pole, I used a single layer and am treating it as a uniform material with material properties similar to that of the composite. When I try to apply an sort of loads, the outcome does not even come close to what I was expecting. Right now it appears that when my pole is supposed to bend, it collapses in on itself and shrinks, then recoils back to its original shape. When I add in gravitational effects, it gets even worse. Everything just falls.
The overall goal of my project is to accurately simulate pole vault as best I can in order to determine the optimal pole length for any given vaulter.
The gist of the paper:
The pole is considered to be a one-dimensional beam with transverse shear, large displacements, large strains, and rotary as well as transverse inertia. Pin joints connect the bottom end of the pole to the ground and the top end of the pole to the vaulter. The pole is modeled using 20 equally long two-node beam elements. The initial velocity of the pole is taken to be the same as that of the vaulter except at the box end which is simply supported. It has a variably thin-walled pip cross-section, with three layers of linearly elastic materials (glass fibre).
The vaulter model consists of 6 segments with five pin joints. The two legs of the vaulter are modeled as a single, two segment leg. The same is true for the two arms.
Here's an image of the initial stance of the pole vaulter

UPDATE: By placing a point mass located at the vaulter's center of gravity I was able to accurately mimic the pole's motion
Here's an image of essentially the goal of what I want my simulation to look it.

If you have absolutely no idea what pole vaulting is. Here's a quick link to give you a good idea on what pole vault entails from an engineering perspective.
Link
At this point in time I have close to nothing completed that gets me closer to my goal. I have modeled the geometry of the pole and the vaulter using simple line bodies in ANSYS DesignModeler. Instead of trying to create the three elastic layers of the pole, I used a single layer and am treating it as a uniform material with material properties similar to that of the composite. When I try to apply an sort of loads, the outcome does not even come close to what I was expecting. Right now it appears that when my pole is supposed to bend, it collapses in on itself and shrinks, then recoils back to its original shape. When I add in gravitational effects, it gets even worse. Everything just falls.





RE: Need Help Simulating Pole Vault Through FEA in ANSYS
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
1. A non-linear dynamic study
2. A moment applied to the pole to bend it, then a compressive force from the vaulter running to further bend it.
3. I don't believe a pin connector of the pole to the vaulter is correct. If that was the case the vaulter's center of gravity would likely stay much more under the connection, they can/do obviously transmit a bending moment using their muscle, so a rigid connection is likely much more accurate.
Beyond that, I don't know enough about the situation or have enough time to dig deeper.
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
I can sort of see how you could possibly make the vaulter's body state function into a function of discretized time and use that in conjunction with an ideal pole motion, but it's going to be very non-trivial. Nevertheless, for any given length of pole, the vaulter would not necessarily use the same body state function, as the vaulter would adapt themselves to the length of the pole.
The single arm bit is a little troubling, since the two arms need to be separated sufficiently to provide a stable frame upon which the vaulter can leverage their body position. Given that, then a pin connection may be OK, since the arm movement is constrained by the arm lengths and body width through the shoulders. The top of page 3 here: http://www.ida.upmc.fr/~hoepffner/research/perche.... shows how much arm movement there is relative to the hand positions. Nevertheless, it would appear from that sequence that the pole might rotate a bit to accommodate the vaulter's body orientation in the last two time points of the diagram.
TTFN (ta ta for now)
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RE: Need Help Simulating Pole Vault Through FEA in ANSYS
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
What I assume based on my results. When i create the point mass, ANSYS is idealizing the inertial effects of the body (that's from the documentation). So when i try to create the vaulter and segment out his limbs, I guess I am not applying any inertial effects?. I have tried applying an acceleration to the body but that yielded nothing different. I am applying moments to the joints as well. Maybe I am using wrong values for moments but changing those as well have yielded no differences.
and technically I am only half way to accomplishing my goal, with the point mass, my vaulter can't do any work on the pole so I can not get an estimate as to how high he will jump, but half way there is significantly better than nothing
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
Since this is a school project I was a bit uncertain how to respond
But since it is friday and the sun is shining
Try this link: https://www.diva-portal.org/smash/get/diva2:998982...
It leads you to a doctoral thesis on wood drying. Perhaps not what interrests you right now but but if you move to the end of the thesis the author has included his licenciate thesis with the title "On the mechanics of pole vaulting" and it includes articles about simulation. The information may be useful for your project.
Good Luck
Thomas
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
...if you get a handle on pole vaulting analysis, could you take a wack at Hungarian vaulting? I know that the Holy Crown of Hungary was IN a vault at Fort Knox and was returned to the Hungarians by Jimmy Carter. So any other vaulting related analysis would be greatly appreciated.
Skip,
Just traded in my OLD subtlety...
for a NUance!
RE: Need Help Simulating Pole Vault Through FEA in ANSYS
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RE: Need Help Simulating Pole Vault Through FEA in ANSYS
Bill McEachern, P.Eng.
Redstone Six Consulting Ltd.
www.redstone6.com