Pedal Force?

[Spetsnazos]

I am running some analysis on the gas pedal and I am near the point of failure(FOS 1.1) which is also dependent on the type of mesh I am using(Solidworks FEA Software). Finer mesh actually brings me below 1.0 FOS.

The pedal force I am assuming is 150 lbs. It is applied to the pedal which pivots forward and then engages a pedal stop to prevent over-travel. The force is then transferred to the pedal stop.

What kind of force are you guys running your analysis on and what justification have you used to support that force? Ive read reports that state 600# is reasonable and others that say 400# is reasonable.

Cheers

[Spetsnazos]

I am running some analysis on the gas pedal and I am near the point of failure(FOS 1.1) which is also dependent on the type of mesh I am using(Solidworks FEA Software). Finer mesh actually brings me below 1.0 FOS.

The pedal force I am assuming is 150 lbs. It is applied to the pedal which pivots forward and then engages a pedal stop to prevent over-travel. The force is then transferred to the pedal stop.

What kind of force are you guys running your analysis on and what justification have you used to support that force? Ive read reports that state 600# is reasonable and others that say 400# is reasonable.

Cheers

[Spetsnazos]

I also gathered this from Steve Fox's article

"The driver can still generate well over a thousand Newton’s (several hundred pounds) force, so the accelerator pedal needs to have an over-travel stop, capable of withstanding this high level of force."

input?

[Drew Price]

If your overtravel stop is in a better place (I am assuming you currently have it down by the pivot) will you still have this problem?

[Dash]

2kN is what we used, seeing as it was specified in the rules.

[Adambomb]

I have personally designed and built pedal brackets designed for a FOS of I'm thinking 1.5 with an input force of I'm thinking 450 lbs. And then I proceeded to bend them during brake test. Just sayin'...

[Spetsnazos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
And then I proceeded to bend them during brake test. Just sayin'... </div></BLOCKQUOTE>

What? Can you clarify this?

[MalcolmG]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Spetsnazos:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
And then I proceeded to bend them during brake test. Just sayin'... </div></BLOCKQUOTE>

What? Can you clarify this? </div></BLOCKQUOTE>
He's not very good at design http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Spetsnazos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Spetsnazos:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
And then I proceeded to bend them during brake test. Just sayin'... </div></BLOCKQUOTE>

What? Can you clarify this? </div></BLOCKQUOTE>
He's not very good at design http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

My spider senses for trolling are tingling...

[MalcolmG]

Not trolling, joking (although I would suggest that something went wrong in his design/manufacture if the design failure load was close to 700lb and it broke).

I'm not sure if I agree with designing the accelerator pedal for the maximum force a driver can possibly apply - most drivers would tend to mostly use a heel-pivoting motion to modulate the throttle, from which they will generate considerably less force than "stomping" like they might do on a brake pedal. I would think somewhere around 200lbs would be more than adequate

[billywight]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Finer mesh actually brings me below 1.0 FOS. </div></BLOCKQUOTE>

Sounds like you shuold either run a coarser mesh for more strength, or have a better understanding of the limitations and assumptions of finite element analysis. (Hint: one of these is not a good idea.)

[Adambomb]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Spetsnazos:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
And then I proceeded to bend them during brake test. Just sayin'... </div></BLOCKQUOTE>

What? Can you clarify this? </div></BLOCKQUOTE>
He's not very good at design http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

Eh, they only yielded a little. And yes, I was stomping the bejeezus out of them, we had some, other, er, "issues." I remember my foot hurting a while afterward. I'm actually quite curious how much force was being applied, back when I actually did squats I did 500 lbs on the machines with about 4 full-range reps. And while it's been a long time since I've done squats, my knees were only bent like 30 degs. in the car, giving a whole lot more leverage, and I was also working heavily off of "last call for acceleration" adrenaline. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Not to say my design couldn't have had a flaw...I did account for the moment in the pedal caused by the bias bar, but also thinking I assumed the force applied to the pedal was perfectly normal to the pedal face, which may or may not have been the case.

[MalcolmG]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
I'm actually quite curious how much force was being applied, back when I actually did squats I did 500 lbs on the machines with about 4 full-range reps. And while it's been a long time since I've done squats, my knees were only bent like 30 degs. in the car, giving a whole lot more leverage, and I was also working heavily off of "last call for acceleration" adrenaline. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Not to say my design couldn't have had a flaw... </div></BLOCKQUOTE>
It's always easier to attribute super-human strength to yourself than the possibility of having made a mistake http://fsae.com/groupee_common/emoticons/icon_razz.gif Although I will note I definitely agree that the position of most drivers does allow significantly more force to be exerted than many seem to think possible. From some rough testing we did using corner-weight scales a few years back, it seemed 2-2.5 times body-weight (with one leg) was roughly the limit for most people (with some safety factor added to account for adrenaline etc)

[Spetsnazos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
I'm actually quite curious how much force was being applied, back when I actually did squats I did 500 lbs on the machines with about 4 full-range reps. And while it's been a long time since I've done squats, my knees were only bent like 30 degs. in the car, giving a whole lot more leverage, and I was also working heavily off of "last call for acceleration" adrenaline. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Not to say my design couldn't have had a flaw... </div></BLOCKQUOTE>
It's always easier to attribute super-human strength to yourself than the possibility of having made a mistake http://fsae.com/groupee_common/emoticons/icon_razz.gif Although I will note I definitely agree that the position of most drivers does allow significantly more force to be exerted than many seem to think possible. From some rough testing we did using corner-weight scales a few years back, it seemed 2-2.5 times body-weight (with one leg) was roughly the limit for most people (with some safety factor added to account for adrenaline etc) </div></BLOCKQUOTE>

we have some beefy 200lb'ers on the team, so 400-600 lbs? Thanks for the heads up http://fsae.com/groupee_common/emoticons/icon_biggrin.gif