Moving Ground modelling: Suspension Bridge/Floating bridge in Adams 1

[Prasiv]

Hello everybody,

I am attempting to model a 'moving ground' in Adams and investigate vehicle dynamics. (something similar to the Tacoma bridge:

https://www.youtube.com/watch?v=j-zczJXSxnw).

I have the measured excitation data signals (displacement in heave and sway; and roll angle) as time histories and along the span of the floating bridge section.
The road builder module in Adams/Car or Adams/Truck module only goes so far as to provide options to model a soft soil or include obstacles such as roughness, sinusoids, curbs, potholes etc, but nothing directly on the moving ground.

1. Has anybody attempted to model a 'moving ground' before? If so, can you suggest how to go about it?
2. Is there an option to include the road excitation signals to the existing 2d/3d road templates in Adams/Car or Adams/Truck or Adams/Chassis as a way forward?
3. Would an option of including spline induced displacement data (translated into SFORCE/GFORCE/AKISPL etc.) applied on the tires/wheels of the vehicle be feasible as opposed to modelling a 'moving ground' itself?
4. As the last alternative, is modelling the road in Adams/View realistic with a discretized mass-spring-damper modelling? Furthermore, can this perhaps be modelled as a flexible body so that it can simulate the Tacoma bridge realistically to be able to include all the excitation signals?

I'm only interested in modelling the 'moving ground' so that it transmits the necessary forces on the vehicle (through the tires) while in motion, and not the structural aspects of the bridge (pillar, piers, cables etc) itself. I'd highly appreciate any help or directions in respect to this topic. Many thanks!

P.S: I couldn't find any thread or post related to this topic in this forum, and therefore decided to pose this question. If there is a similar thread / post on this topic already, please redirect me to it and I will delete my post to prevent duplication.

 

[GregLocock]

OK, I agree, you can't really use a road surface. That's a fairly weird thing to do, but is entirely feasible. You could try the 4 poster rig in the Ride plug in. This applies a time history of displacements to the contact patch of each tire.

It's a sufficiently odd situation that MSC themselves might take a look at it, if you can Dr Andy on the case then you'll have a lot of fun. Down the track you might want to model the bridge itself.

Cheers

Greg Locock


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[Prasiv]

Hi @GregLocock,
Thank you for your response.
1. I was attempting to explore the Adams/Ride plug-in to enable the excitations. The 4-post rig in the ride plug-in provides only static vehicle analysis. However, I'm interested to apply these environmental excitations when the vehicle is in motion (I'm coupling certain vehicle specific events as well). Even with the static analysis, one can only apply vertical excitation (and roll? translated to superimpose vertical excitation). Do you suppose one could apply lateral excitation in the 4-post rig in addition to the vertical excitation?
2. If you would be so kind as to share Dr. Andy's email (or redirect me to where I can gather his email ID), I will attempt to establish contact with him through MSC to take this topic forward with his inputs.
3. I take your advice to pursue modelling the bridge.

It's interesting how there are always topics that push the envelope of development and progress.

Many thanks once again.

Cheers,
Pramod

 

[GregLocock]

1 You could hand modify the rig to remove the lateral constraints and apply lateral forces. I know what you mean by static but that isn't the usual use of the word in ADAMS, it is a dynamic event at 0 longitudinal velocity.
2 Sorry, I don't have any contact details. Try Support. I expect he has been put out to pasture.
3 Good oh, that'll be more useful.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?