RESULTS ON POST #75: FEA Analysis on Fender/Cowl Brace

MGizzle · 01-21-2008, 12:57 PM

RESULTS ON POST #75

Hey guys,

I am trying to buy an aftermarket bracet (probably the GT SPec) but am trying to make an "educated" guess before I do so. Hence, I am trying to model a fender brace (stock or whatever, even the GT Spec later) in CAD so that I can run a FEA on it. Below you can see a picture of a simplified cowl brace made out of structural steel and 3mm thick. It is very basic but my problem is I have no dimensions or information regarding the braces. I also don't want to take mine off since I don't have aftermarket ones and don't want to buy any yet since I don't know what I want to get for sure.

Anyhow, can somebody PLEASE give me some basic dimensions of the stock brace that will allow me to make an accurate model of our brace so that I can run it in FEA?? Stretch, I know you like to measure stuff and I know you got aftermarket braces so measure the stock one dude, pleaseeee!!!

This is the basic info I need.

1. OD of bolts used to fix brace to chassis. (the model uses 10mm ID's)
2. Lenghts between all the 4 holes (model has 350 long brace, hole to hole, and 60mm between holes)
3. Thickness of brace
4. Any ideas as far as how this brace is loaded? (right now I am using a simple vertical force called "F" of 1000N in the image and am fixing the two points between the two front door mounts).

The model shown above is not supposed to be accurate in any way. I just did it as a "foundation" for the actual one (just messin around with the software a bit) but I was hoping that with the help of you guys I can create an accurate model and write a report on it. I will also try to model the GT Spec one so if you have some basic dimensions on that brace please let me know. If not it's OK. I will get some probably in a couple of months and will CMM them to create the model.

Hope you guys see some value in this and your feedback/input is appreciated.

Later.

ItalianStallion · 01-21-2008, 01:08 PM

what are you using to develope your load cases?
dont forget to run basic hand calcs on edge margin.
you should also include your max principle stress plots as well.
keep us posted cheers.

fullerton · 01-21-2008, 01:08 PM

Interesting... I have the TiC braces at home and can measure them from you.

4banger · 01-21-2008, 01:13 PM

Very interesting project.
I'm almost certain Stretch does not have these because he doesn't think that they will be much of an improvement.

**Kevin** · 01-21-2008, 01:24 PM

This is like the last stiffening mod you should consider and several that you should consider before this one if you didn't even want to make it your last mod.

ESmooth · 01-21-2008, 01:46 PM

Other than doing this for the sake of messing around with it, are you really worried that one will make that much more of a difference than another? Just about anything in the aftermarket is so much better than stock that the differences between the various options are really inconsequential when they are installed on the car...kinda like going from fishing with a rod and reel to dropping some dynamite in the lake...if you see where im going.

mtskibum16 · 01-21-2008, 02:13 PM

Cool project. It's kind of funny...I have been doing this exact same thing except I am designing my own brace and I'm going to CNC it from aluminum. I wanted to model the stock brace and run FEA on it and then run FEA on my brace. I too was stuck at dimensions though. I have my brace all done in CAD (just by eye) and all I need are dimensions to plug in. I was trying to get someone to mail me one of their stockers but no luck so far. I actually one I can get my hands on but right now I don't feel like going out in the cold to take it off. Let me know if you get anything though.

4banger · 01-21-2008, 02:15 PM

Quote:

Originally Posted by ESmooth

Other than doing this for the sake of messing around with it, ...

That reason alone is enough to make it worth while for a lot of people. Some of us just like trying to figure out why one thing performs better than another. Besides, maybe MGizzle will find out Brand X brace is really junk and doesn't stiffen any more than stock. Being a suspension guy yourself, you ought to know how much junk is out there in the suspension world.

mtskibum16 · 01-21-2008, 02:15 PM

Quote:

Originally Posted by 4banger

Very interesting project.
I'm almost certain Stretch does not have these because he doesn't think that they will be much of an improvement.

I seem to remember him giving in and getting a set.

ESmooth · 01-21-2008, 02:48 PM

Quote:

Originally Posted by 4banger

That reason alone is enough to make it worth while for a lot of people. Some of us just like trying to figure out why one thing performs better than another. Besides, maybe MGizzle will find out Brand X brace is really junk and doesn't stiffen any more than stock. Being a suspension guy yourself, you ought to know how much junk is out there in the suspension world.

On many parts I would agree, but in this case, its pretty much been proven that anyhting out there is better than stock by a pretty fair margin, enen the factory 07 stuff...have fun with it though.

***sciolist*** · 01-21-2008, 03:26 PM

Quote:

Originally Posted by ESmooth

Other than doing this for the sake of messing around with it, are you really worried that one will make that much more of a difference than another? Just about anything in the aftermarket is so much better than stock that the differences between the various options are really inconsequential when they are installed on the car...kinda like going from fishing with a rod and reel to dropping some dynamite in the lake...if you see where im going.

And going from the OE unit to the burliest thing available is kind of like upgrading from white to red shoelaces before a marathon... but it's still an interesting study.

mtskibum16 · 01-21-2008, 04:20 PM

Quote:

Originally Posted by ESmooth

On many parts I would agree, but in this case, its pretty much been proven that anyhting out there is better than stock by a pretty fair margin, enen the factory 07 stuff...have fun with it though.

They all may be better than stock but that doesn't mean they are all equal. Why wouldn't you want the best?

**Turninconcepts.com** · 01-21-2008, 05:06 PM

Mgizzle - I'll do you a solid on this one. I have my stock one here somewhere, and I have a TiC one that got a bit chipped in shipping. I'll send both to you. Sand or scrap off the powder coat and take some true measurements.

Shoot me a PM with your address, and I'll get those on the way.

fullerton · 01-21-2008, 05:12 PM

Quote:

Originally Posted by Turninconcepts.com

Mgizzle - I'll do you a solid on this one. I have my stock one here somewhere, and I have a TiC one that got a bit chipped in shipping. I'll send both to you. Sand or scrap off the powder coat and take some true measurements.

Shoot me a PM with your address, and I'll get those on the way.

Looks like I can skip my measurements then.

colingilchrist · 01-21-2008, 05:21 PM

I've got a stock one somewhere. I'll see if I can measure it up for you. I got the GTSpec braces by the way. They made a world of difference. The GTSpec use 6 holes on the door side, the original two, and a top set and bottom set that bolt into your door hinges. They really increased the stiffness of the front end considerably.

01-21-2008, 12:57 PM	#1
MGizzle Professional STI Racer Car: 05 STi OBP Fav Mod: Data Acq System Location: Warren, Michigan Posts: 782 Join Date: Jul 2006 Trader Rating: (1)	RESULTS ON POST #75: FEA Analysis on Fender/Cowl Brace RESULTS ON POST #75 Hey guys, I am trying to buy an aftermarket bracet (probably the GT SPec) but am trying to make an "educated" guess before I do so. Hence, I am trying to model a fender brace (stock or whatever, even the GT Spec later) in CAD so that I can run a FEA on it. Below you can see a picture of a simplified cowl brace made out of structural steel and 3mm thick. It is very basic but my problem is I have no dimensions or information regarding the braces. I also don't want to take mine off since I don't have aftermarket ones and don't want to buy any yet since I don't know what I want to get for sure. Anyhow, can somebody PLEASE give me some basic dimensions of the stock brace that will allow me to make an accurate model of our brace so that I can run it in FEA?? Stretch, I know you like to measure stuff and I know you got aftermarket braces so measure the stock one dude, pleaseeee!!! This is the basic info I need. 1. OD of bolts used to fix brace to chassis. (the model uses 10mm ID's) 2. Lenghts between all the 4 holes (model has 350 long brace, hole to hole, and 60mm between holes) 3. Thickness of brace 4. Any ideas as far as how this brace is loaded? (right now I am using a simple vertical force called "F" of 1000N in the image and am fixing the two points between the two front door mounts). The model shown above is not supposed to be accurate in any way. I just did it as a "foundation" for the actual one (just messin around with the software a bit) but I was hoping that with the help of you guys I can create an accurate model and write a report on it. I will also try to model the GT Spec one so if you have some basic dimensions on that brace please let me know. If not it's OK. I will get some probably in a couple of months and will CMM them to create the model. Hope you guys see some value in this and your feedback/input is appreciated. Later. This ad is not endorsed by this member. Please register or login to hide this ad. Last edited by MGizzle : 02-29-2008 at 01:10 PM. Reason: Updating Post #75 with Results

01-21-2008, 01:08 PM	#2
ItalianStallion Junior STI Driver Car: 07 SWP STI Fav Mod: Tim Bailey Protune Location: Seattle Posts: 128 Join Date: Mar 2007 Trader Rating: (5)	Re: FEA Analysis on Fender/Cowl Brace what are you using to develope your load cases? dont forget to run basic hand calcs on edge margin. you should also include your max principle stress plots as well. keep us posted cheers.

01-21-2008, 01:08 PM	#3
fullerton abracious Car: AW GDF-D Fav Mod: Track time Location: Near a 100oct pump Posts: 16,542 Join Date: Oct 2005 Trader Rating: (10)	Re: FEA Analysis on Fender/Cowl Brace Interesting... I have the TiC braces at home and can measure them from you.

01-21-2008, 01:13 PM	#4
4banger Professional STI Racer Car: 05 WRB STi Fav Mod: TiC AST's - 7/6K Location: Chesapeake, VA Posts: 624 Join Date: Feb 2005 Trader Rating: (3)	Re: FEA Analysis on Fender/Cowl Brace Very interesting project. I'm almost certain Stretch does not have these because he doesn't think that they will be much of an improvement.

01-21-2008, 01:24 PM	#5
Kevin Admin Car: Silver 2004 STI Fav Mod: The Driver Location: Southern California Posts: 12,024 Join Date: Jan 2001 Trader Rating: (1)	Re: FEA Analysis on Fender/Cowl Brace This is like the last stiffening mod you should consider and several that you should consider before this one if you didn't even want to make it your last mod.

01-21-2008, 01:46 PM	#6
ESmooth STI Driver Car: 06 Stage 2 STI Location: Redondo Beach, CA Posts: 264 Join Date: Dec 2006 Trader Rating: (0)	Re: FEA Analysis on Fender/Cowl Brace Other than doing this for the sake of messing around with it, are you really worried that one will make that much more of a difference than another? Just about anything in the aftermarket is so much better than stock that the differences between the various options are really inconsequential when they are installed on the car...kinda like going from fishing with a rod and reel to dropping some dynamite in the lake...if you see where im going.

01-21-2008, 02:13 PM	#7
mtskibum16 Professional STI Driver Car: 05 Subaru WRX STi Location: Montana Posts: 461 Join Date: May 2006 Trader Rating: (1)	Re: FEA Analysis on Fender/Cowl Brace Cool project. It's kind of funny...I have been doing this exact same thing except I am designing my own brace and I'm going to CNC it from aluminum. I wanted to model the stock brace and run FEA on it and then run FEA on my brace. I too was stuck at dimensions though. I have my brace all done in CAD (just by eye) and all I need are dimensions to plug in. I was trying to get someone to mail me one of their stockers but no luck so far. I actually one I can get my hands on but right now I don't feel like going out in the cold to take it off. Let me know if you get anything though.

01-21-2008, 05:06 PM	#13
Turninconcepts.com Authorized Vendor Car: 04/08STI 95SVX 86E30 Posts: 5,034 Join Date: Jul 2003 Trader Rating: (53)	Re: FEA Analysis on Fender/Cowl Brace Mgizzle - I'll do you a solid on this one. I have my stock one here somewhere, and I have a TiC one that got a bit chipped in shipping. I'll send both to you. Sand or scrap off the powder coat and take some true measurements. Shoot me a PM with your address, and I'll get those on the way.

01-21-2008, 05:21 PM	#15
colingilchrist Lurker Car: 04 Subaru WRX STi Fav Mod: custom tune Location: lynnwood Wa Posts: 4 Join Date: Jan 2007 Trader Rating: (0)	Re: FEA Analysis on Fender/Cowl Brace I've got a stock one somewhere. I'll see if I can measure it up for you. I got the GTSpec braces by the way. They made a world of difference. The GTSpec use 6 holes on the door side, the original two, and a top set and bottom set that bolt into your door hinges. They really increased the stiffness of the front end considerably. This ad is not endorsed by this member. Please register or login to hide this ad.