Dummy Crash Simulation problems

Dear Forum,

 

for a project I want to simulate the effect on a person who is driving a car with 13.88 m/s (50 km/h)
and crashes into an obstacle with a 90° angle towards the obstacle (straight front crash).
The person is represented by a dummy (50% Male), the seat structure was modeled by altair, as well as the dummy.
I created two seatbelts with the Hypercrash tool Belt Generator (Hypercrash --> Safety --> Belt Generator) and deformed the seat with the seat deformer (old)
(Hypercrash --> Safety --> Seat Deformer --> Geometrical displacement (old)).
Due to simplification I removed the complete lower sector of the seat group and replaced it with a rigid body, which is linked to
the floor and the seat.

I built the model as follows:

 

Loadcases:
-Initial velocity: applied to all parts of the model (13.88 m/s)
-Imposed velocity: A function, which decreases the speed from 13.88m/s to 0 within 30 ms. Applied to all parts but the dummy itself.
-Gravity load: To maintain physical correctness of the dummys motion.
-Added Mass: Applied to all nodes of the dummy to be representative for the human weight.

Boundary Conditions:
-BC for the seat: All degrees of freedom are locked except for the translation in X-axis (which is the direction of motion).
This is applied only for the floor and the ground part of the seat.

 

Contact Interfaces:
-Interior contact: Contact between the two seat layers (was set by altair when I imported the model, I did not change any values)
-Seat to floor: Contact seat to floor (TYPE7)
-Feet to floor: Contact feet to floor (TYPE10)
-Seatbelt to dummy: Contact upper/lower seatbelt to dummy/seat (TYPE7)
-Dummy to seat: Contact Dummy to seat (TYPE7)

 

The problems I am facing now are:

-The Runtime for a single simulation is about 9500 seconds. Can this be regarded as normal, considering the model complexicity?
-Results of the simulation differ too much from expactations/reality
 -->Normally I would have expected the backrest to at least do a little motion, but it remains in its position.
-Because of the constraints of the seatbelts, the head of the dummy experiences a very high acceleration.
 -->Is there any chance, that the Belts ease a little bit  (in the beginning) and afterwards tension up, just like in reality?
-All elements of the part 'LINK', ID:6 delete on the beginning of every simulation. I could not figure out the reason for that, neither in the starter file, nor in the engine file.

-During the Simulation it reaches one Point, where all the masses go into one single point/node but I can not figure out, why (see attached Video)

 

 

Please correct me if I am rootedly wrong with my assumptions.

 

Attached you can find my model files.

 

PS: I am aware of the initial penetrations within the seat.

Thanks in advance.

 

 

Greetings.