How do I set the hard stop distance (where the spring is maximally compressed) for a Spring Damper object?

Philip Oesterle-Pekrun

I am using the Vehicle Tools extension in MotionView, which I guess is in some way a part of HyperWorks (or now renamed to HyperMesh?) 2023. Basically my model stems from selecting this after opening "HyperMesh 2023":

So, on to the actual issue at hand. Whether I use the Vehicle Tools assembly wizard from the Vehicle Tools Ribbon or create a "Spring Damper" component from the Model Ribbon, I am unable to see an option to set the hard stop or maximum compression distance of the spring damper. When I set the spring stiffness to a small value like 0.1N/mm (for a car weighing about 1Ton) and run a simple NPost Simulation, the spring has some maximal compression beyond which it will not go. That shows that there is a hard stop for the spring, but I do not know where I can edit this value. I have looked everywhere for it, including in the (by default seperate) damper system (also a spring damper, but with 0 stiffness and a finite damping coefficient). In every spring damper component you have these same options:

I have checked the documentation, and it does not mention hard stops or maximum compression distance. But as I explained, the value for the hard stop must exist by default, as the springs clearly have a certain default maximum compression distance in simulations. I will greatly appreciate any help on this. It is a simple issue but really holding up my workflow. Thanks.

Here are screenshots of the modelling window and simulation result for context:

(vehicle body hidden in mdl)

(you can clearly see that, at 0.1N/mm, the springs compress a maximal distance at a hardstop)

GTT Adam

Hi Philip,

SpringDamper entities do not feature hardstops, however a ShockAbsorber entity does. A ShockAbsorber can be added to a model using the Entity Browser, and navigating to Entities >> Vehicle Tools >> Components >> ShockAbsorber. You can enable to Vehicle Tools Extension by navigating to File >> Extension Manager >> then enabling the Vehicle Tools Extension. There are also methods to implement hardstops through the use of individual property file -based BumpStop entities and ReboundStop entities. Lastly, they can be implemented using Force entities and a reference curve.

If you assembled your model with internal or external jounce/rebound dampers, then they will be implemented by Force entities

 

If you chose property file based hardstops, then they will show as individual BumpStop and ReboundStop entities:

 

Documentation for the ShockAbsorber, as well as how to use the BumpStop and ReboundStop, can be found below:

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_shock_absorber_mvx_r.htm#reference_q1w_fz5_qwb

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_bumpstop_r.htm#reference_sgb_gn2_nwb

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_rebound_stop_r.htm#reference_sgb_gn2_nwb

 

Thanks,

Adam Reid

Sudip_Chavan

Hi Philip,

You need to activate that Travel Lock System under Frnt SLA Susp -> Frnt Coil Spring -> Travel Lock.

You can also update Jounce and Rebound values in Vehicle Dataset.

 

Hope this helps!

Regards

Sudip Chavan

GTT Adam

Hi Philip,

SpringDamper entities do not feature hardstops, however a ShockAbsorber entity does. A ShockAbsorber can be added to a model using the Entity Browser, and navigating to Entities >> Vehicle Tools >> Components >> ShockAbsorber. You can enable to Vehicle Tools Extension by navigating to File >> Extension Manager >> then enabling the Vehicle Tools Extension. There are also methods to implement hardstops through the use of individual property file -based BumpStop entities and ReboundStop entities. Lastly, they can be implemented using Force entities and a reference curve.

If you assembled your model with internal or external jounce/rebound dampers, then they will be implemented by Force entities

 

If you chose property file based hardstops, then they will show as individual BumpStop and ReboundStop entities:

 

Documentation for the ShockAbsorber, as well as how to use the BumpStop and ReboundStop, can be found below:

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_shock_absorber_mvx_r.htm#reference_q1w_fz5_qwb

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_bumpstop_r.htm#reference_sgb_gn2_nwb

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_rebound_stop_r.htm#reference_sgb_gn2_nwb

 

Thanks,

Adam Reid

Philip Oesterle-Pekrun

Adam Reid_21142 said:

Hi Philip,

SpringDamper entities do not feature hardstops, however a ShockAbsorber entity does. A ShockAbsorber can be added to a model using the Entity Browser, and navigating to Entities >> Vehicle Tools >> Components >> ShockAbsorber. You can enable to Vehicle Tools Extension by navigating to File >> Extension Manager >> then enabling the Vehicle Tools Extension. There are also methods to implement hardstops through the use of individual property file -based BumpStop entities and ReboundStop entities. Lastly, they can be implemented using Force entities and a reference curve.

If you assembled your model with internal or external jounce/rebound dampers, then they will be implemented by Force entities

 

If you chose property file based hardstops, then they will show as individual BumpStop and ReboundStop entities:

 

Documentation for the ShockAbsorber, as well as how to use the BumpStop and ReboundStop, can be found below:

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_shock_absorber_mvx_r.htm#reference_q1w_fz5_qwb

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_bumpstop_r.htm#reference_sgb_gn2_nwb

https://help.altair.com/hwdesktop/hwx/topics/motionview/entity_rebound_stop_r.htm#reference_sgb_gn2_nwb

 

Thanks,

Adam Reid

Sorry, took me a while to work it out, but I found that using the shock absorber entities rather than SpringDamper was the most straightforward solution, and it works, thank you so much. Also thank you for the MotionSolve Vehicle Tools E-Learning course you made--that is what I am working off of and it was very helpful.

 

Best,

Philip Oesterle-Pekrun