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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. Modell_Dummy_Sitzgruppe_0001.rad Modell_Dummy_Sitzgruppe_0000.rad Modell_Dummy_Sitzgruppe_0000.M00 Simulation_Video.avi
Guest posted a topic in Altair MotionView, Altair MotionSolve and Altair Inspire (Motion)Hello, i tried the new belt-pulley-simulation in MotionView. The assembly was correct and i attached a rotary motion to the first pulley. In the animation can be seen that this pulley ist rotating, but not the belt and other pulleys. Is there an option for friction or others necessary settings? Thanks and greetings Pierre
How can I simulate belt drive systems on Motionview? Is there any toolkit to use? Thanks in advance!
Hi sir, I am trying modeling belt as nlfe but solution does not converge. Could you make any suggestion for convergence especially for the belt friction and other nonlinear parameters. It is not possible to learn exact friction parameters for belt but I guess you have some approximations for the nonlinear parameters. Please find the all necessary files for the model at the attachment. Additionaly, I am trying to measure belt flapping. Krank_NR_Angular_Velocity_6.txt NLFE.mdl NLFE.xml