RD-V: 0130 Tied Surface Contact

Figure 1. A cube impacting a square plate

The impact algorithm is evaluated by the impact of a cube on a square plate.

Three different contact interfaces are studied:

/INTER/TYPE7
/INTER/TYPE10 with I_TIED =0 and I_TIED =1

Options and Keywords

The following keywords are used in the models.

Model Files

Before you begin, copy the file(s) used in this problem to your working directory.

RD-V-0130.zip

Model Description

Units: Mg, mm, s.

The plate is 254 mm square and 25.4 mm thick. The cube length is 25.4 mm. The parts are modeled using solid elements and linear elastic material. An initial velocity of 5080 mm/s is applied to the block in the z direction. The model contains no further constraints.

Three different contact interfaces, /INTER/TYPE7, /INTER/TYPE10 with rebound and /INTER/TYPE10 without rebound, are tested to model the impact between the plate and the block.

In this analysis, /INTER/TYPE10 is compared with /INTER/TYPE7.

Iterations

The following iterations are evaluated:

Results

Iteration 1:

The results of the TYPE7, TYPE10 interfaces with rebound and TYPE10 interface without rebound contacts are represented below:

Figure 3. Results of the TYPE7, TYPE10 interfaces with rebound and TYPE10 interface without rebound contacts

Global Kinematics:
The global momentum can be plotted using the time history output. The results show that the global z momentum for all interface models correspond exactly to the theoretical momentum of 0.6452 $\frac{M g}{m m / s}$ mentioned in RD-V: 0100 Impact Momentum.

The results for the individual interfaces are not the same due to the differences in the contact stiffness of the interfaces. Using TYPE10 without rebound shows that the secondary nodes are tied to the main surface after the impact.

Iteration 2:

In this iteration an /IMPDISP is used instead of /INIVEL. The purpose is to evaluate and compare the behavior of the plate after impact.

Figure 7. TYPE7, TYPE10 with rebound and TYPE10 without rebound contacts results

Figure 8. a) Z displacement of node 940 and 13 using TYPE7; b) Z displacement of node 940 and 13 using TYPE10 with rebound

Figure 9. Z displacement of node 940 and 13 using TYPE10 without rebound

Type7: As expected, during contact the impactor rebounds and the plate is pushed in the other direction.
Type10 with rebound: The results are similar to those of TYPE7.
Type10 without rebound: The plate is tied to the impactor as expected. After contact, the plate follows the movements of the impactor

Iteration 3:

In this iteration, the impactor is moved in Z direction with an /IMPDISP until it is tied to the plate. Then a second /IMPSIP is used to move the impactor in the X-direction. The purpose is to evaluate and compare the behavior of the plate after impact with TYPE 7 and TYPE10 with rebound.

Figure 10. Results of TYPE7 and TYPE10 with rebound contacts

Figure 11. a) X displacement of node 1198 and 9 using TYPE7; b)X displacement of node 1198 and 9 using TYPE10 with rebound)

Type7: As expected, the impactor rebounds at contact and the plate does not move in the X-Direction. With TYPE7, sliding contact in the X-Direction is detected.
Type10 with rebound: During the impact, the plate is tied to the impactor as expected. After contact, the plate follows the movement of the impactor.

Conclusion

The study shows that each of the contacts TYPE10 with rebound and TYPE10 without rebound behaves as expected. With TYPE10 with rebound, the impactor rebounds and the plate moves in the other direction. With TYPE10 without rebound, the plate is tied to the impactor and follows its movement.