Rear lower control arm loading 1

[cd632]

thread800-169037

Hi All,

I've had a look through the above thread after my search of the forums.

What i'm trying to do, i'm designing lower control arms for my sports sedan (front wheel drive). Now I'm trying to calculate the forces that will be acting on the LCA.

So far, my understanding goes as such;

-Car will be driven mainly on the street with occasional circuit racing
-Design the LCA to accept a "shock" from a pothole
-Factor of Safety of 4-5

How can I begin calculations to workout the forces present on each mounting point of the control arm so I can load the data up in FEA? (LCA mounts to hub, shock to LCA, LCA to chassis)

I appreciate your help,

Kind Regards,
Chris

 

[GregLocock]

"work out the free body diagrams for each arm"

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[cd632]

Thanks for the reply Greg;

What about the force from the spring/shock? Could you give me a simple example on the FBD calculation?

Cheers,

 

[GregLocock]

Spring/shock/jounce bumper forces are usually handled via an estimate of the maximum likely to be seen. Assuming it is a coilover suspension then you could replace that by a rigid link for these purposes (yes it is more complicated than that but this stuff is to get you in the ballpark).

I've included an FBD. Fz and Fy are obvious by inspection, Tx less so.





Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[cd632]

Greg,

I had a look at that diagram, it looks similiar to what I have at the moment although I have less forces, what is the force in the Y direction acting from?

Sorry to pick your brains, I've looked through most of my books on LCA design/compliance but I can't seem to find any in the books I have.

How would you pick your "maximum seen" force from the shock combo? F=kx ?
What force would you use as a "maximum seen" for the CP to begin the FBD analysis?

Once again Greg, appreciate your effort and time.