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chemicalboy

I need help with timing belt dynamic simulation!

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chemicalboy

hey guy I'm new to this forum,and I want urgent help please!!

I need to make a dynamic simulation for pulley/timing belt assembly.

I tried using "cylinder on plane" joint type but i cannot make the correct selection. any1 knows how to?

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chemicalboy

what I need to do is to make one pulley to drive the timing belt and the belt to drive the other pulley

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chemicalboy

I can't upload here the file is too big..but i rendered a pic hoping it would help you figure

WCR.jpg

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shift1313

When you created the pully/belt setup, did you use the design synchronous belt feature?

 

regardless, when you are in dynamic simulation you need to insert a joint. There is a joint called "belt". It will let you select both pulleys. The standard origin of each part should be correct(i.e. no need to select anything for the origin). Just make sure the arrow hats are correct. They arent labeled x,y,z but there will be 1arrow, 2 arrows and 3. Once you insert this joint, and add your torque to one pulley, the other will move. Depending on how your pulley is connected to the shaft, you may need to insert a contact joint as well.

BeltHelp.jpg

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chemicalboy

yea i use synchronus belt..and i did exactly what u told me..but it says the mechanism is over constrained by 1 degree..what is that from?

i attached a pic with the error here.

Untitled.jpg

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shift1313

Either something is grounded or your assembly is rigid. You need to right click on your belt assembly, go to properties and make it Flexible. When you create a belt setup it automatically grounds the belt which is okay(i dont think you can "un-ground" it) but with a rigid assembly everything will be locked.

 

When you right click on your assembly and iProperties is selected. Go to the Occurrence tab. Here you will see flexible. Also note the icon in the feature tree to let you know this subassembly is flexible.

belthelp2.jpg

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chemicalboy

I made it flexible and it still has 1 more degree of freedom..here's a simplified model of my work if u can make it move..dude wat's the lightning sign beside the icon of the synchronous belt of mine?? I didn't find it in your assembly picture!!

assembly link:

mediafire.com/file/tnxmh1h2ugq/wcrmod3.rar

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shift1313

i cant get that site to load. Open your file in dynamic simulation and click on the Mechanism Status button and upload a screen shot of it.

 

The lightning icon means you chose manual solver when you created your part. Mine doesnt have have that because I did not use the solver. I chose the belt width, made the pulley sizes and placed them on the plate holes and had the belt size appropriately.

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chemicalboy

Is that lightning sign the reason for the conflict?will it be able to move appropriately if i chose the standard lenghts? here is the attached pic

mechanism status.jpg

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shift1313

No the lightning bolt will(should) not have any effect on that. It only lets you know how the sub-assembly was designed. There is the manual method(no solver and no icon), the manual solver and the auto solver. The auto one i believe is a circular icon similar to adaptive but not the same.

 

You can see you have 1 redundant joint. you can see it says chain 1 of 3 and lists the chain below. Cycle through all 3 and see which one has the redundant constraint. Im going to guess that since you have two sets of belts/pulleys that is it. You wont need two belt/pulley joints if they are connected by a shaft(fixed to the shaft).

 

Can you manually move the assembly in dynamic simulation? if you click(and hold) on one of your pulleys you can create a force vector and make the assembly move.

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chemicalboy

nope whenever i try to move the assembly it is fixed to the ground..I still don't know what joints you want me to remove?

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chemicalboy

guys i still dunno how to move the damn belt!!! :(

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JD Mather
guys i still dunno how to move the damn belt!!! :(

 

Moving the actual belt is a waste of time. You can rotate the wheels and the represent belt joint, but actually moving the belt is way too processor intensive and requires a bit of trickery. I post some examples that my students have done - but I will not bother with the painful technique.

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chemicalboy

fine..how can i rotate the pulley?

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shift1313

ive been messing with your assembly for probably an hour now with no luck getting it to work as is. When you open it up in Dynamic Simulation it puts an exclamation next to the component with redundancy. Ive gone as far as starting a new assembly with only the main housing and one of your belt assemblies with no luck.

 

However, if you go back and edit your belt/pulley using design accelerator and change the belt from detailed to solid your pulleys will move. Remember I said you have to set the assembly as Flexible(right click on the name in the feature tree and make it flexible). Anytime you have a sub assembly with mates in it(motion) you need to make it flexible so those mates will work.

 

JD is right, making the belt move is a seriously tough task. What do you need to do with this model?

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chemicalboy

I need to demonstrate its working idea..that the two motors in the middle can rotate the pulleys and drive the belt with magnets bolted along its circumference to stick to ferromagnetic surfaces without sliding..I'm not building a prototype so getting this assembly to work is crucial.

concerning Ineventor tasks I want to make a dynamic simulation for the drive system and get a video rendering ,and also stress analysis to main components such as shafts,frame,couplings,bolts,nuts etc..

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shift1313

How much does it weigh and how powerful are each magnet? metal/metal isnt going to have a high mu value so you will need some stout magnets which means your motors will have to overcome that.

 

At any rate that is a very involved and by no means novice task as JD mentioned. I know you dont have a ton of time but you need to play around with a simple model but there is way too much going on and too many constraints for you to get anywhere.

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JD Mather

If I get some time I think I can get it to actually move along a "floor", but the belt will not be actually moving and the magnets will not be engaging/disengaging as real world.

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chemicalboy

guys that all sound depressing :( what do you suggest to do?other than changing the assembly design :)

 

p.s:I'm ready to spend anytime and do watever it takes to get that think functioning

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