Collision between 2 bodies

[RubenNavas]

Hello. I am writing this entry to askif it is possible to perform a 2D simulation of the collision between two bodies (see the attached Figure).

Case description

Figure.png (11.34 KiB) Viewed 216 times

The simulation involves two solid bodies: a clamped beam (solid 1) and a rigid quadrangular object (solid 2). Initially, the beam is undeformed, and the squared-cross-section quadrangle rests above the beam. Over time, the second solid is displaced downward with a pre-defined vertical velocity, 𝑣. The aim is to study the beam's displacement and stress distribution due to the interaction between both objects over time. Additionally, the simulation should account for non-linear behavior (plasticity) regarding the beam, while assuming the second solid remains rigid (undeformable).

Thanks for the help.

[kevinarden]

viewtopic.php?t=7312

viewtopic.php?t=7005

[RubenNavas]

Hello. Firstly, thank you for your rapid response and the provided material. However, after extensively reviewing the attached links, I am still unable to understand how to model the interaction between the two objects.

To perform the simulation, I have considered that the beam is made of iron, while the pressing object is made of a material with a very high Young's modulus to ensure its rigidity. Additionally, I am using the "ElasticSolver" for both solids. Regarding the boundary conditions, the beam is clamped on its left face, and the pressing solid has a vertical downward velocity of 0.5 m/s.

After running the simulation, the pressing object traverses the beam without interacting with it (see the attached image). I assume this is due to an error related to a missing boundary condition linking both solids. Could you please explain how to model the missing or erroneous parts of the simulation? Additionally, I have attached the .sif file and the simulation folder.

Thank you for your help!

[kevinarden]

In the solver section you have to have

Apply Contact BCs = Logical True

to apply contact conditions

In the boundary conditions you have to define the contact conditions

Boundary Condition 2
Name = "leading"
Target Boundaries(1) = 8
Force 1 = Variable Time
Real
0.0 100
0.08 100
0.0801 0
0.4 0
end
Mortar BC = 3
Plane Projector = Logical True
Galerkin Projector = Logical True
Normal-Tangential Displacement = Logical True
Mass Consistent Normals = Logical True
End

Boundary Condition 3
Name = "struck"
Target Boundaries(1) = 9
Normal-Tangential Displacement = Logical True
Mass Consistent Normals = Logical True
End

[kevinarden]

This is covered in Chapter 9.2

https://www.nic.funet.fi/pub/sci/physic ... Manual.pdf

[RubenNavas]

Hello. Once again, thanks for the provided help. I have reviewed your attachements and performed some modifications. However, I am not yet obtaining suitable results.

The undertaken modifications are:
I have added the following flag to the calmped beam and pushing object solvers:

Code: Select all

Apply Contact BCs = Logical True

I have set the following boundary condition to the pushing object (I want it to be displacing at a downwards velocity of 0.5 m/s):

Code: Select all

Boundary Condition 1
  Target Boundaries(1) = 5 
  Name = "CircleDisplacement"
  Displacement 2 = Variable Time
    Real
    0.0 0.0
    1 -0.5
  end
  Mortar BC = 3 
  Plane Projector = Logical True
  Galerkin Projector = Logical True
  Normal-Tangential Displacement = Logical True
  Mass Consistent Normals = Logical True
End

I have set the following boundary condition to the beam upper surface (the one that contacts the pushing object):

Code: Select all

Boundary Condition 3
  Target Boundaries(1) = 4 
  Name = "Contact"
  Normal-Tangential Displacement = Logical True
  Mass Consistent Normals = Logical True
End

After the simulation, the results are catastrophic. The objects do not properly contact and become largely deformated (see the attached figure). Moreover, I am receiving the following Elmer warnings:
WARNING:: DetermineContact: No Lagrange multiplier field associated with linear system: displacement
WARNING:: DetermineContact: No contact type given, assuming > Slip Contact <
WARNING:: DetermineContact: There are normals with conflicting signs: 96

Do you know waht I am missing?

Thanks for your help.

[kevinarden]

contact.png (21.9 KiB) Viewed 148 times

Added comments in sif to explain my reasons for the changes

case.sif

(4.29 KiB) Downloaded 24 times