Mechanical Event Simulation
Mechanical Event Simulation
(OP)
Just wondering if anybody ca help me with a problem I am having with a MES model I am trying.
I have created a simple MES setup with a plate that is constrained and a brick that is falling with gravity toward the plate. Instead of the brick hitting the plate it goes straight through it. I have set up the surface contact with the top surface of the plate and the bottom surface of the brick, but it doesn't seem to make any difference.
Any help would be greatly appreciated.
I have created a simple MES setup with a plate that is constrained and a brick that is falling with gravity toward the plate. Instead of the brick hitting the plate it goes straight through it. I have set up the surface contact with the top surface of the plate and the bottom surface of the brick, but it doesn't seem to make any difference.
Any help would be greatly appreciated.





RE: Mechanical Event Simulation
By the way, what version of Algor are you using?
Garland
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
www.borowskiengineering.com
Lower Alabama SolidWorks Users Group
http://laswug.borowskiengineering.com
RE: Mechanical Event Simulation
Thanks for your reply. Firstly, yes I am using surface to surface contact and the contact pair is active. Secondly, I have tried a number of different time steps, with the same result. Thirdly, I am using Algor v.16 which i know has a tolerance issue in the contact pair options, which i have changed from 2.54e-1 to 0.01 mm as i am working in mm not inches.
Thanks again for your help.
Tim
RE: Mechanical Event Simulation
Garland
RE: Mechanical Event Simulation
Another way to approach this would be to instead of having the brick fall towards the plate have them almost initially touching with just a very small gap. Give the brick an initial velocity of what speed it should be going according kinematics and specify a small starting time step. If no matter how small you make the time step contact still is not detected you will probably need to play around with your mesh. I would start with the element size of the plate elements being larger than that of the brick. If this doesn't work try vice versa...then same size on each.
Once you do get the model to recognize contact one more things which pops to mind is the sharp corners of the brick. If you have convergence issues shortly after cotact occurs it will likely be due to these.
Good luck!
-Brian
RE: Mechanical Event Simulation
Just for fun, I ran a block falling onto a plate. I was using v.19, but here are some of the specifics:
Time Step: 0.01s
Distance block above plate: 0.5 inches (sorry, didn't think about you working in metric, so 12.7mm)
I reduced the convergence criteria to 0.01 inches (this may not be entirely accurate, but I was just trying to get some settings that would work, not get really accurate results)
I applied gravity (negative z-direction, 386.4in/sec -- perpendicular to the plate)
I have the block hitting the plate with a contact distance of 0.25 inches and a maximum penetration (I don't think you have this in v.16) of 0.1 inches. These numbers are huge, but I have a large mesh on my block and plate of about 0.5 inch.
The block is made of steel and the thin plate (0.1 inches) is made of Nylon 6/6, so I get some permenant deformation and good "bounce" from the block.
RE: Mechanical Event Simulation
Tim
RE: Mechanical Event Simulation
In my mind, for something as simple as a brick and flat plate, it is easier to "Copy: Join" to build the internal mesh. If you aren't familiar with this, let me know. I also "Copy", but not join, to make sure that the nodes of the brick line up with the nodes of the plate. Then, I make sure that my contact distance is 1/2 the length of an element edge. This should make certain that, as long as my time steps are small enough, the nodes have to make contact.
If I'm just trying to learn how to make this contact happen, place the block about 1/2" above the plate, make the contact distance 0.49 and the penetration 0.5". Put a really small time step and a really small duration, so you don't fill your hard drive with useless data. Run "Monitor" so you can see what is happening and output results from every time step.
If you keep having trouble, e-mail me and archive of your model...my address can be found on my website. I'm not sure if v.19 can even read back to v.16, but I can take a look.
Garland
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group