Feature/shell contact using ghost particle

[WeiyiVirtonomy]

The previous PR was closed due to the incorrect merge.

TODO:

• Add test cases back
• Check sliding under different resolutions of solid and shell

[WeiyiVirtonomy]

@DongWuTUM Hi Dong, I opened a new PR for contact. I'll add the deleted test cases back later this week.

[DongWuTUM]

Hi Weiyi, test_3d_shell_self_contact cannot run. When compling, it shows 'ParticleGeneratorSurface': base class undefined. Could you help me solve this? Thanks.

[DongWuTUM]

@WeiyiVirtonomy Hi Weiyi, could you sent me the reference data (and test results if it is Okay from your side) of the test cases you have tested? Including the fluid-shell, shell-shell, shell-solid cases if possible. In this way, I don't need to collect these data again. Thank you!

[WeiyiVirtonomy]

@WeiyiVirtonomy Hi Weiyi, could you sent me the reference data (and test results if it is Okay from your side) of the test cases you have tested? Including the fluid-shell, shell-shell, shell-solid cases if possible. In this way, I don't need to collect these data again. Thank you!

Hi, Dong, I have uploaded the reference data of FSI extracted from the figures and the SPH simulation results to Dropbox https://www.dropbox.com/scl/fo/oba51l7uyo9npoy9yzvo7/AE0wAqExM-eVyGO73uxLn4k?rlkey=llp63qrqteed0eyger2646veb&st=7koohawb&dl=0. As for the contact problems, I only created some simple tests without verification.

[DongWuTUM]

@WeiyiVirtonomy Hi Weiyi, could you sent me the reference data (and test results if it is Okay from your side) of the test cases you have tested? Including the fluid-shell, shell-shell, shell-solid cases if possible. In this way, I don't need to collect these data again. Thank you!

Hi, Dong, I have uploaded the reference data of FSI extracted from the figures and the SPH simulation results to Dropbox https://www.dropbox.com/scl/fo/oba51l7uyo9npoy9yzvo7/AE0wAqExM-eVyGO73uxLn4k?rlkey=llp63qrqteed0eyger2646veb&st=7koohawb&dl=0. As for the contact problems, I only created some simple tests without verification.

Thank you!!!

[DongWuTUM]

Hi Weiyi, test_3d_shell_self_contact cannot run. When compling, it shows 'ParticleGeneratorSurface': base class undefined. Could you help me solve this? Thanks.

@WeiyiVirtonomy Could you also have a look on this problem?

[WeiyiVirtonomy]

Three ring contact

Reference paper: Yang, Laursen
The big ring is modeled as a solid, while the medium and small ones are modeled as a shell.
Unlike the paper, frictionless contact is used in the simulation. Other parameters are the same.

Result

The paper didn't provide the exact time of Fig. 16, so I only took some screenshots at time frames with similar deformation.

Instability

Under a resolution of dp = thickness / 4.0, self-penetration of the medium ring is observed, probably because the displacement within one step is too large.
If repulsion force is only generated when particle distance is within 0.5*(dp1+dp2), the shell might not have enough time to react. Therefore, I changed the contact surface to 2.3*dp_ave (cut-off radius of the kernel). With this modification, no self-penetration is observed, but strong hourglass effect can still be seen:

Refining dp to thickness / 8.0, the hourglass effect disappears as shown above.

[DongWuTUM]

Great!!!

[WeiyiVirtonomy]

Oil tank

An oil tank with oil inside collided with a truck at a speed of 20m/s. The oil tank is modeled as an elastic cylindrical shell, while the truck is a rigid volumetric cylinder.
The properties and geometries are all estimated.
The simulation includes the contact between the elastic tank and the rigid truck, the fluid-solid interaction between the fluid and the tank, and the solid-fluid interaction between the tank and the fluid.
The tank is fixed at the bottom (the red points):

With dp = 0.25m (10 particles per diameter):

The fluid looks not so good. Some strange wave-like shapes can be seen at the bottom, caused by the initial interaction between shell and fluid. In hydrostatic tests, high velocity can be seen at the bottom of the tank due to force from fluid.

The weird shape exists even with resolution refinement.