"Create RBE2 Spider" tab not active in Motionview student version 2017.2

Hello,

I am trying to create a flexible lower control arm using the FlexPrep utility tool in 2017.2 student version. I am facing the following issues:

1. 'Create RBE2 Spider' tab not active, hence I am not able to switch to HyperMesh to create a RBE2 spider whose center is one of the interface nodes.

2. As a workaround, I manually created the RBE2 spider in OptiStruct and exported the solver deck as a *.fem file. When I try to use this file for creating a flexbody. I am getting an error.

I have pasted a snapshot of the flex prep utility and the error message when I try to generate the flexbody below. I have also attached the *.fem file and *.out file

image.png.a4cabf20ac0280a31a47ca5832756ce6.png .

image.png.cead868d70aad8a48e527808ea5992b4.png

image.png.f5726fd718e5e58baff7bb8e9e9c1b12.png

Please take a look and let me know how this issue can be resolved.

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Felipe M Leila

Hello Sushanth,

The issue with the Tab is probably a limitation in the Student Version.

Your workaround is correct. But you didn't assign any property/material to the flex body component, that is why you got an error.

Altair Forum User

Felipe,

Ok, thank you for pointing it out!

Regards,

Sushanth

Altair Forum User

Felipe,

I have another question regarding the flex bodies. Do the following factors - Vehicle weight, CG, Wheel base, front braking ratio, axle ratio etc.. have any effect on the static ride analysis? I have a flex lower control arm and I am doing static ride analysis. No matter what values I give for the above factors, the stress and strain values of the lower control arm are not changing. Do you have any idea why this is happening?

Thanks

Felipe M Leila

Hello Sushanth,

Sorry the late response.

It depends on your model, if you are performing a Static Ride analysis in a half-vehicle for example, the vehicle is fixed to the ground in the CG position. Therefore, increasing the vehicle weight will not affect the simulation unless you want it to do so.

The same may be true for the other parameters.

I recommend you to take a look on our online help about the analysis you are simulating to verify if the parameters affect or not your simulation based on your model, hal-car, full-vehicle, trucks, etc.

https://altairhyperworks.com/hwhelp/Altair/2018/help/mv/mv.htm?static_ride_anaylsis_mv_ug.htm

https://altairhyperworks.com/hwhelp/Altair/2018/help/mv/mv.htm?kinematics_and_compliance_mv.htm

Best regards,

Felipe.

Chris Coker_21312

Sushanth-

The parameters you are changing only influence the calculated parameters seen in the SDF outputs (for parameters such as anti-lift, anti-dive, etc). If you are running static ride analysis, and the vehicle weight changes, then your spring rate (and spring preload) will likely need to change, to account for the change in vehicle weight. Changing the preload will change the load into the suspension, which will change the displacement, stress, strain in the flexbody.