Gauging Interest, ISC Front Control Arm

[SkAsphalt]

Originally Posted by CSG David

You too SkAsphalt.

I was just quoting what is below his name haha

[Calum]

Originally Posted by SkAsphalt

Calum, don't be that guy.

I know. If this was a 'hey, look what we're selling' thread I'd keep my trap shut. But OP is asking about the communities interest. I'm sure I'm in the minority with this, but I'm also pretty sure I'm not alone.

[CSG David]

Originally Posted by Calum

I know. If this was a 'hey, look what we're selling' thread I'd keep my trap shut. But OP is asking about the communities interest. I'm sure I'm in the minority with this, but I'm also pretty sure I'm not alone.

We all know who are going to buy these arms.

[ISC Suspension]

Originally Posted by Yoniyama

At first, I was excited by this proposal. Finally, a better front control arm!

Among other things, I installed the following on my Toybaru:

1 $1,000 for a carbon fibre driveshaft;
2 $2,000 for a set of five 16-inch forged wheels (yes 16-inch!) that weighs 12lb each;
3 $800 for a pair of 2-piece front rotors (-5lb each);
4 $550 for a set of light-weight Cusco anti-roll bars (hollow in rear);
5 $600 for a 15lb fly-wheel; and
6 $60 for ultra-light lug nuts (25 grammes each).

As you can see, reducing unsprung weight is a high priority for me.

But sorry, front control arms that are 2lb heavier (each) but also 5X stronger do not interest me. Partly because my Toybaru is not about to compete in the Dakar Rally.

2lb heavier (in unsprung weight) but 5X stronger is a compromise (heavier weight for greater strength), not necessarily an out-right improvement.

The proposition would be IRRESISTIBLE if it was:
a 2lb lighter (each); and
b 2 X stronger.

Then it would be an improvement in every aspect. I would be VERY interested if the street price is under $1,000/pair.

But perhaps I am not your target/typical customer.

We're working on this right now sir, stay tuned for an update!

[mike156]

This seems like a show car piece. Add a $500 polish and you'll have a winner.

Anybody that cares about performance is going to want adjustability and a lighter weight part. What you are offering for adjustability is what is already available with the stock arms and they are heavier than stock so it's a miss there too. I like what you are trying to do, but the approach has serious limitations that likely won't work for a large client base. What you are offering is higher stiffness as strength on the stock arm really isn't a concern. Stiffness likely could have some benefits here but you're using the wrong terms. Of course, you are using factory type bushings though so go ahead and throw out the stiffness benefits because that bushing is still going to be the less stiff part of the system.

You would be better off taking down your FEA work shown though as anybody that knows anything about engineering knows you are doing it wrong.

First off, the arm is free to pivot vertically in actual use, the arm carries no vertical load yet that is what you are showing. The arm is responsible for lateral and longitudinal loads, the only bending it would see in the direction you have loaded it would be from BUCKLING under lateral load. Even then it would likely be in the opposite direction.

The fixations are all wrong too, although the way you have constrained it would likely produce higher than real stresses since you have done a surface constraint. The reality is, the inner bushing of the pivots are constrained and could be considered rigid and you have a high stiffness spring between the inner bushing and the arm if you are using factory/urethane bushings.

You should look at the approach used by OEMs. MANY are using forged aluminum arms at this point, but cars like the EVO have VERY stiff aluminum arms that are still reasonably light. Take some design cues from them and you'll be ahead in the design game. A little hint, the control arm is basically an I-beam to support lateral and longitudinal loads with two fixed points with the load application site cantilevered out from them.

[xwd]

There are companies out there (mainly JDM at this point) who make weld-in stiffeners for our stock front control arms if that's all you are interested in.

http://www.auto-style.jp/item_img/ACT10566350003_3.jpg

AutoFactory and Buddy Club also sell what look like stock arms modified to be stiffened.

I like the Cortex Racing or Racer X arms for a race application.

http://www.cortexracing.com/shop/tac...rz-fr-s-ft-86/

[Dezoris]

At this price point it's only going to appeal as a motorsports product and you are talking a very small fraction of buyers would consider it.

It was already said but for the average street user with some track time, things like rubber bushings and stamped steel arms serve their purpose to help keep road manners and protect car from nasty frame damage if you crack a curb or pot hole.

What most owners on this forum need is a matching set of good quality front rear arms that allow for easy camber adjustment under load along with optional roll center correction. They don't have to be some esoteric material or construction but somewhat more rigid, and ideally somewhat lighter and most importantly easy to adjust that will survive 4 season usage.

Most all of the products available now won't last one winter without being destroyed.

[Captain Snooze]

Originally Posted by Yoniyama

At first, I was excited by this proposal. Finally, a better front control arm!

Among other things, I installed the following on my Toybaru:

1 $1,000 for a carbon fibre driveshaft;
2 $2,000 for a set of five 16-inch forged wheels (yes 16-inch!) that weighs 12lb each;
3 $800 for a pair of 2-piece front rotors (-5lb each);
4 $550 for a set of light-weight Cusco anti-roll bars (hollow in rear);
5 $600 for a 15lb fly-wheel; and
6 $60 for ultra-light lug nuts (25 grammes each).

As you can see, reducing unsprung weight is a high priority for me.

But sorry, front control arms that are 2lb heavier (each) but also 5X stronger do not interest me. Partly because my Toybaru is not about to compete in the Dakar Rally.

2lb heavier (in unsprung weight) but 5X stronger is a compromise (heavier weight for greater strength), not necessarily an out-right improvement.

The proposition would be IRRESISTIBLE if it was:
a 2lb lighter (each); and
b 2 X stronger.

Then it would be an improvement in every aspect. I would be VERY interested if the street price is under $1,000/pair.

But perhaps I am not your target/typical customer.

Everything's a compromise.
It is not 2 pounds of unsprung weight; the arm pivots. That is, the weight at the pivot is sprung and the weight at the wheel is unsprung.

[Captain Snooze]

This is an uneducated opinion piece.
Those Whiteline bushes look like they would be a right pain to adjust. One has to press out the bush then guess how much to rotate it before pressing it back in. Best of luck try to get both sides the same.

[ISC Suspension]

Thanks for the input folks.
We will keep this thread updated as we continue to move forward making changes, etc

[Crazy Drew]

Not to seem like a jerk but it appears as though the constraints you have in your FEA are of little good with the actual forces seen by the arm. There is no bending in that direction. Constrain it from the 2 inner pivots and set the forces of the outer ball joint to be fore/aft on the car and in/out of the car. Also, the bevels/chamfers you have on the inner profile directly result in a stress riser, as seen by your first FEA. Could that be radiused to prevent that?

Edit* Just to clarify, I mean the forces along the Z and X axis of your drawings as referenced by your origin indicator in one photo.

[ISC Suspension]

Originally Posted by mike156

This seems like a show car piece. Add a $500 polish and you'll have a winner.

Anybody that cares about performance is going to want adjustability and a lighter weight part. What you are offering for adjustability is what is already available with the stock arms and they are heavier than stock so it's a miss there too. I like what you are trying to do, but the approach has serious limitations that likely won't work for a large client base. What you are offering is higher stiffness as strength on the stock arm really isn't a concern. Stiffness likely could have some benefits here but you're using the wrong terms. Of course, you are using factory type bushings though so go ahead and throw out the stiffness benefits because that bushing is still going to be the less stiff part of the system.

You would be better off taking down your FEA work shown though as anybody that knows anything about engineering knows you are doing it wrong.

First off, the arm is free to pivot vertically in actual use, the arm carries no vertical load yet that is what you are showing. The arm is responsible for lateral and longitudinal loads, the only bending it would see in the direction you have loaded it would be from BUCKLING under lateral load. Even then it would likely be in the opposite direction.

The fixations are all wrong too, although the way you have constrained it would likely produce higher than real stresses since you have done a surface constraint. The reality is, the inner bushing of the pivots are constrained and could be considered rigid and you have a high stiffness spring between the inner bushing and the arm if you are using factory/urethane bushings.

You should look at the approach used by OEMs. MANY are using forged aluminum arms at this point, but cars like the EVO have VERY stiff aluminum arms that are still reasonably light. Take some design cues from them and you'll be ahead in the design game. A little hint, the control arm is basically an I-beam to support lateral and longitudinal loads with two fixed points with the load application site cantilevered out from them.

We understand that this is not actual real world load data, this is a prototype and we are undergoing stress test, the research and development is not yet completed on this. The test previously shown was a straight pull as if the arm had no bushings and was directly bolted to a surface.

We are well aware that this is not a typical force that will occur while driving. But in the process of trying to deliver parts that are reliable and high performance we are taking every possible scenario into consideration. This is the only stress test we had direct access to at the moment to show you so we apologize if its not the one you wanted to see.

We are currently working on getting more real world data as well as making the arm LIGHTER and MORE ADJUSTABLE without sacrificing STRENGTH.

[SubieNate]

I think his point was that the load case is one that the arm would never see in the real world. If your design load case is flawed then any design you base off of it is going to be inherently flawed.

Design and analysis tools are only as good as the monkey driving them. In trying to reduce weight while analyzing incorrectly, strength in the actual load condition could be unknowingly compromised. You have to start with a solid understanding of where and how the loads are applied, follow that with an understanding of how the load is going to flow through the part, and optimize from there. If any of the baseline assumptions are wrong then the process and therefore the product are flawed from the start.

Cheers
Nathan

[ISC Suspension]

Originally Posted by SubieNate

I think his point was that the load case is one that the arm would never see in the real world. If your design load case is flawed then any design you base off of it is going to be inherently flawed.

Design and analysis tools are only as good as the monkey driving them. In trying to reduce weight while analyzing incorrectly, strength in the actual load condition could be unknowingly compromised. You have to start with a solid understanding of where and how the loads are applied, follow that with an understanding of how the load is going to flow through the part, and optimize from there. If any of the baseline assumptions are wrong then the process and therefore the product are flawed from the start.

Cheers
Nathan

The entire point of an FEA analysis is to show worst case senario results. These models show an example of that because this is a STATIC analysis (the chassis mounted bushings are shown as SOILD with no movement in the X, Y or Z axis). Yes the control arms will see other forms of stess when cornering etc. THIS model only shows the bending force analysis that these control arms could see when in use. There will ALWAYS be force similar to this on the arm. The actual forces will be less due to the flex and give of real bushings.

However, the direction of the force (purple arrows) should be pushing up on the arm and not down because the wheel would be taking all of the downward force. Since this is a simple cantilever beam analysis, where the part is almost symmetric over the center plane, the results would be comparable.

Everyone seems to be referring to lateral forces and movement while this is just a simple example of flexing the control arm.

This is NOT the only information used in the design process for these control arms. Just something for us to show the world what we are doing and a sample of how we actually use data analysis for our products to maintain the up most quality.

The first FEA model shows the maximim static strain and the second shows the area with the highest deflection.

Again this whole thread was to gauge interest in our new control arms that we are developing. We are currently working on weight reduction while maintaining rigidity and strength.