×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

How to determine suspension ride frequency in adams car

How to determine suspension ride frequency in adams car

How to determine suspension ride frequency in adams car

(OP)
I have a modelled the suspension of a vehicle and now I'm trying to determine its ride frequency, which simulation would I need to run to achieve this.

RE: How to determine suspension ride frequency in adams car

Do you have a full vehicle model? If so:

I think you'll find static vehicle characteristics tells you one quick estimate. There are several frequencies in the report

Bounce node loc. wrt H-pt. mm 1943.44
Bounce natural frequency Hz 1.38
Pitch node loc. wrt H-pt. mm -903.64
Pitch natural frequency Hz 1.94
Ride frequency ratio 1.36
Front
Wheel hop natural freq. Hz 10.57 10.58 10.55
Wheel tramp natural freq. Hz N/A
Front ride frequency Hz 1.31

Rear
Wheel hop natural freq. Hz 9.00
Wheel tramp natural freq. Hz 11.82
Rear ride frequency Hz 1.77

The bolded ones are the ones we usually call ride frequencies but they are really corner frequencies

One problem is that in a real car the 'ride frequency' varies with amplitude, so a given frequency(s) only applies to a given track and speed.

The 4 poster test is a good one for theoretical ride frequencies, otherwise you just run it over surfaces with various wavelengths at various speeds.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: How to determine suspension ride frequency in adams car

(OP)
Hello Mr Locock,

Thank you for taking the time to reply me

I'm having a few issues

1} the FSAE model has bellcranks on the front and rear suspension but the vehicle I am trying to model has direct dampers on the front suspension and a pushrod setup with bellcranks on the rear suspension.
I don't know how to modify the geometry on the front suspension to make it a direct damper.

2} Is there any way to assess ride frequency by analysing just the front and rear suspensions individually?

3} yes it's a full vehicle model of the FSAE 2018 template but when I try to run the base fsae 2018 model to determine static vehicle characteristics i get the following error

---- START: ERROR ----
This command cannot be processed until a model has been defined.
Maybe you need to add a FILE/MODEL=pathname, OUTPUT=prefix command to the command (*.acf) file.
---- END: ERROR ----

command: preferences/solver=CXX
command: preferences/list,status=on
PREFERENCES:
SIMFAIL = NOSTOPCF
Contact Geometry Library = (not loaded)
Thread Count = 1
Library Search Path = Not Set
Status Message = Off
Solverbias = CXX (C++ Solver)

command: control/routine=abgTire::con901,func=user(901,465,98,104,1,2)
command: control/routine=abgTire::con901,func=user(901,473,99,105,1,4)
command: control/routine=abgTire::con901,func=user(901,483,107,113,1,6)
command: control/routine=abgTire::con901,func=user(901,491,108,114,1,8)
command: output/nosep


---- START: ERROR ----
This command cannot be processed until a model has been defined.
Maybe you need to add a FILE/MODEL=pathname, OUTPUT=prefix command to the command (*.acf) file.
---- END: ERROR ----

command: control/routine=abgVDM::EventInit, function=user(5,1,8,0,3,6,8,17)
command: control/routine=abgVDM::EventRunNext, function=user(0)
command: control/routine=apresolver::consub, function=user(1111,14,0,0,0,0,507,508,60,63,18)
command: !
command: stop


Finished -----
Elapsed time = 0.00s, CPU time = 0.00s, 0.00%

ERROR: Cannot load results! File 'DEMO_1_svc.res' not found.
Simulation is complete.








RE: How to determine suspension ride frequency in adams car

(1) look in help for the options with your suspension template.
(2) If you know the sprung mass at one axle then the ride frequency is just 1/2/pi*sqrt(wheelrate*2/SM), get wheelrate from the vertical test
(3) Looks like the model didn't build. What files are in your working folder?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close