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Simulate a falling body that impacts on a deformable surface

Posted 5 mag 2011, 11:13 GMT-4 Version 3.5a 4 Replies

Kate
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Hello,

I would like to know if Comsol can simulate the deformation of a plastic surface as a consequence of the impact with a falling body (a ball, for example).

If so, would you be so kind to give me some suggestions?


Thank you very much!

Best regards,
Caterina
4 Replies Last Post 31 lug 2015, 02:36 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 5 mag 2011, 15:18 GMT-4
Hi

My understanding is that COMSOL, as any FEM programmes, is not really tailored for multibody simulations. But with some equation writing and COMSOL open access to the equations, I still believe you can do a good job about analysing the deformation of a ball bouncing off a hard surface (with COMSOL ;)

--
Good luck
Ivar
Hi My understanding is that COMSOL, as any FEM programmes, is not really tailored for multibody simulations. But with some equation writing and COMSOL open access to the equations, I still believe you can do a good job about analysing the deformation of a ball bouncing off a hard surface (with COMSOL ;) -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago 6 mag 2011, 10:57 GMT-4
Finite element programs have difficulties simulating rigid to rigid multibody contact problems as Ivar mentioned. However, in this case, one of the impacting bodies is flexible (plastic) so there is no problem. You can find many papers/examples on say drop testing simulations (flexible body impacting rigid surfaces – I have one paper in the upcoming NAFEMS 2011 conference), or shot peening (rigid spheres impacting a flexible plastic body).

I don’t recall seeing any similar COMSOL example but it should be doable. Getting the right material damping properties in these problems is important.

Nagi Elabbasi
Veryst Engineering
Finite element programs have difficulties simulating rigid to rigid multibody contact problems as Ivar mentioned. However, in this case, one of the impacting bodies is flexible (plastic) so there is no problem. You can find many papers/examples on say drop testing simulations (flexible body impacting rigid surfaces – I have one paper in the upcoming NAFEMS 2011 conference), or shot peening (rigid spheres impacting a flexible plastic body). I don’t recall seeing any similar COMSOL example but it should be doable. Getting the right material damping properties in these problems is important. Nagi Elabbasi Veryst Engineering
Kate
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Posted: 1 decade ago 7 mag 2011, 11:23 GMT-4
Dear all,

Thanks for your support! I will follow your suggestions!

Best regards,
Caterina
Dear all, Thanks for your support! I will follow your suggestions! Best regards, Caterina
Mustafa Al-Kamal
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Posted: 1 decade ago 31 lug 2015, 02:36 GMT-4
Dear Nagi,

I'm trying to model impact simulation of an upper beam rotates and hit another beam below it. I have used multibody dynamic physics along with the contact formulation using the penalty factor method. The forces are due gravity only. I'm using comsol 5.0 and as I have read in the comsol documents (structural mechanics module) that the contact formulation does not work with impact problems and we need always to check conservation of energy and momentum to check the results. On the other hand, I have solved the problem analytically using conservation of energy and momentum. The shear in comsol, was higher than the analytical solution, but the moment and deflection were smaller than the analytical. In addition, I'm having large contact force due to impact leading to increase shear and reduces the velocity after impact which leads to decrease moment and deflection in comsol as compared with analytical solution.
I just want to match the results because I'm getting twice the shear from comsol and 1/6 moment and deflection from comsol as compared with analytical solution.

Any suggestions would be very helpful, thanks in advance.

My Best Regards

Mustafa Al-Kamal
Dear Nagi, I'm trying to model impact simulation of an upper beam rotates and hit another beam below it. I have used multibody dynamic physics along with the contact formulation using the penalty factor method. The forces are due gravity only. I'm using comsol 5.0 and as I have read in the comsol documents (structural mechanics module) that the contact formulation does not work with impact problems and we need always to check conservation of energy and momentum to check the results. On the other hand, I have solved the problem analytically using conservation of energy and momentum. The shear in comsol, was higher than the analytical solution, but the moment and deflection were smaller than the analytical. In addition, I'm having large contact force due to impact leading to increase shear and reduces the velocity after impact which leads to decrease moment and deflection in comsol as compared with analytical solution. I just want to match the results because I'm getting twice the shear from comsol and 1/6 moment and deflection from comsol as compared with analytical solution. Any suggestions would be very helpful, thanks in advance. My Best Regards Mustafa Al-Kamal

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