# RD-V: 0110 Friction

The contact friction forces are studied and compared to an analytical solution.

The contact friction forces are studied between a fixed and moving plate. The friction and reaction forces are used to calculate a displacement which is compared to the applied displacement.

## Options and Keywords Used

- /INTER/TYPE24

## Input Files

Refer to Access the Model Files to download the required model file(s).

The model files used in this problem are available in:

/radioss/verification/contact

## Model Description

$${V}_{m}$$ | $$T$$ | Total Displacement |
---|---|---|

565 mm/s | 0.009 s | Y=2.54 mm |

-102 mm/s | 0.001 s | Z=0.0508 mm |

The following system is used: mm, s, Mg.

### Simulation Iterations

The contact reaction force was output to the time history file. The reaction force from the imposed velocity applied to the top block’s positive y face were also output to the time history file. The surface to surface /INTER/TYPE24 contact interface was studied.

## Results

- $$u$$
- Theoretical displacement in the y direction
- $L$
- Length of the top block
- $w$
- Width of the top block
- $h$
- Height of the top block
- $E$
- Young's modulus
- $F$
- Total resultant force at the imposed velocity, calculated from /ANIM/VECT/FREAC
- $R$
- Total contact reaction forces in the z direction from /TH/INTER
- $\mu $
- Coefficient of friction

The calculated displacement, where the imposed velocity was applied in the y direction was 2.530 mm. When compared to the applied 2.540 mm displacement, there was a numerical error of 0.39%.

### Conclusion

The contact interface friction calculation results in minimal error of 0.39% when compared to theory.

^{1}Buechler, Miles, Amanda McCarty, Derek Reding, and R. D. Maupin. "Explicit finite element code verification problems." In 22nd SEM International Modal Analysis Conference, Dearborn, MI. 2004