FT-86 SpeedFactory LCA by Verus - Lightest LCA for the Twins - Development Thread

[Shankenstein]

Originally Posted by NotEric6

I had no idea you had access to such machines! Very cool sir. That's the issue we're running into with him testing. They've been running the machines 24/7, he can't even get it on the test stand on Sundays sometimes.

Regarding mechanical shock testing, it's typically done with a pneumatic/hydraulic system like this:


It builds pressure then pushes the parts up in one-shot. High force (40 - 200G) and short duration (5 - 20 ms).

For milder shock testing where you're not going to have fixture or parts resonance... you can use a shaker table (this one is using a slip table).


Doing a control arm would be complicated. You'd need to fix both 2 of 3 pivot points and apply the shock load on the third (just like with the Instron testing above).

It's probably cheaper to just throw it on a race car and beat on it.

[cdrazic93]

Wouldn't be cheaper if you crashed because of the product...lol

[Shankenstein]

For Mike's situation, you may have luck finding a giant pendulum (like the charpy or izod) impact tester.


Many universities and labs will have these, and it's an easy way to wang on stuff in a controlled manner.

[Xuningshen]

The structural designer in me loves the truss look of your design. makes me feel better compared to the other ones.

Originally Posted by eric6

Figured it about time to update the thread . So we started development with a few overall goals and then capitalized on them with extensive FEA analysis. FEA (Finite Element Analysis) uses a numerical, computer based technique to solve complex scenarios. A variety of scenarios can be predicted, such as stress, heat transfer, vibration, fatique, and other physical effects. The power of FEA lies in the ability to solve problems that would be extremely difficult or impossible to solve by hand. Similar to CFD, FEA partitions the structure into a finite number of elements. These elements form standard shapes, such as triangles, quadrilaterals, hexagons, etc. The use of these standard shapes allows the development of a governing equations that can related stresses and displacement within the element. Please keep in mind that FEA is a tool, and in the wrong hands, it can be like shooting a target blindfolded. You need accurate inputs for an accurate output. .........

Please let us know if you have any questions. We will be testing these units off car soon, which should let us know how well our FEA analysis lines up with real world results. Then... onto some race cars .

[CSG Mike]

Originally Posted by Shankenstein

Regarding mechanical shock testing, it's typically done with a pneumatic/hydraulic system like this:


It builds pressure then pushes the parts up in one-shot. High force (40 - 200G) and short duration (5 - 20 ms).

For milder shock testing where you're not going to have fixture or parts resonance... you can use a shaker table (this one is using a slip table).


Doing a control arm would be complicated. You'd need to fix both 2 of 3 pivot points and apply the shock load on the third (just like with the Instron testing above).

It's probably cheaper to just throw it on a race car and beat on it.

That's exactly what I had in mind.

[phobos512]

Originally Posted by Shankenstein

Regarding mechanical shock testing, it's typically done with a pneumatic/hydraulic system like this:


It builds pressure then pushes the parts up in one-shot. High force (40 - 200G) and short duration (5 - 20 ms).

For milder shock testing where you're not going to have fixture or parts resonance... you can use a shaker table (this one is using a slip table).


Doing a control arm would be complicated. You'd need to fix both 2 of 3 pivot points and apply the shock load on the third (just like with the Instron testing above).

It's probably cheaper to just throw it on a race car and beat on it.

This is how WE do shock testing. (To be clear, this is not my video, but my product has been through this test at this facility.)

[ame="https://www.youtube.com/watch?v=x_a-XjdGV_s"]MIL-STD-901D shock test, 20 feet - YouTube[/ame]

[Dimman]

Originally Posted by NissanGuy

These aluminum arms are meant to be lighter than SPL's titanium? If so, props.

Titanium's denser than aluminum, plus has a worse stiffness to weight.

Aluminum, especially the aerospace grades, can outperform titanium in certain aplications.

Between 6061 and 7075... 2024?

[VerusEric]

Originally Posted by Dimman

Titanium's denser than aluminum, plus has a worse stiffness to weight.

Aluminum, especially the aerospace grades, can outperform titanium in certain aplications.

Between 6061 and 7075... 2024?

SPLs only use titanium for the lock nut and the bolt on their clamp I believe. The LCA itself is 6061-T6.

I'm away on business for my day job. I will write up our findings when I return home on Saturday.

[VerusEric]

Alright so after Sunday's test, we found out that the adjuster fails prematurely when cyclically loaded. We believe we actually instigated the failure slightly by heating up the unit by loading it at 10 Hz (friction/movement builds heat). Regardless, we don't believe it would have reached our goal of 50,000 cycles. It did last fairly long though and in most cases, the unit wouldn't have failed in our opinion. It would have still lasted multiple seasons but not long enough for us to take it to production.

We have already machined up replacement adjusters and ordered high strength alloy rod ends. This will add about 0.2 lbs per LCA, however, we have effectively increased the strength of these two pieces by 75%. Realistically, we don't need to re-test, but we want to.

On top of that, we are going to test the OEM unit and see how it fairs in the same tests we are testing our LCA in. The person who is testing said he can probably get it on the bench next weekend.

Thanks for your patience,
Eric

[Calum]

Originally Posted by NotEric6

Alright so after Sunday's test, we found out that the adjuster fails prematurely when cyclically loaded. We believe we actually instigated the failure slightly by heating up the unit by loading it at 10 Hz (friction/movement builds heat). Regardless, we don't believe it would have reached our goal of 50,000 cycles. It did last fairly long though and in most cases, the unit wouldn't have failed in our opinion. It would have still lasted multiple seasons but not long enough for us to take it to production.

We have already machined up replacement adjusters and ordered high strength alloy rod ends. This will add about 0.2 lbs per LCA, however, we have effectively increased the strength of these two pieces by 75%. Realistically, we don't need to re-test, but we want to.

On top of that, we are going to test the OEM unit and see how it fairs in the same tests we are testing our LCA in. The person who is testing said he can probably get it on the bench next weekend.

Thanks for your patience,
Eric

Pics or it didn't happen!! I want to see those results, please.

[Shankenstein]

Originally Posted by NotEric6

Alright so after Sunday's test, we found out that the adjuster fails prematurely when cyclically loaded. We believe we actually instigated the failure slightly by heating up the unit by loading it at 10 Hz (friction/movement builds heat). Regardless, we don't believe it would have reached our goal of 50,000 cycles. It did last fairly long though and in most cases, the unit wouldn't have failed in our opinion. It would have still lasted multiple seasons but not long enough for us to take it to production.

We have already machined up replacement adjusters and ordered high strength alloy rod ends. This will add about 0.2 lbs per LCA, however, we have effectively increased the strength of these two pieces by 75%. Realistically, we don't need to re-test, but we want to.

On top of that, we are going to test the OEM unit and see how it fairs in the same tests we are testing our LCA in. The person who is testing said he can probably get it on the bench next weekend.

Thanks for your patience,
Eric

FMEA squad up!

Even when threads are "helped" with a glass bead blast, hardening, or heat treatment... there's always stress concentration due to shape. Many times, you've got residual stresses too.

Fatigue testing will find the weak point and initiate a crack. At this point, the crack is its own stress concentration. The material's toughness dictates how much concentration... and it's just a matter of cycles before the part is #rekt.

Thanks for posting the news publicly. There is no failure in R&D... we follow the cycle:
test --> anomaly --> problem definition --> root cause --> corrective action --> re-test

It's only a failure once you've put it in the field, and it seems like you guys are going the extra mile to ensure customer satisfaction.

[Captain Snooze]

Originally Posted by Shankenstein

and it seems like you guys are going the extra 1.62 kilometers to ensure customer satisfaction.

Fixed.

[Shankenstein]

Originally Posted by Captain Snooze

Fixed.

Fixed:Fixed: ... you guys are going the extra 1.073 kilometers to ensure customer satisfaction.

(50,000 of 75,000 shocks)

[VerusEric]

Originally Posted by Shankenstein

FMEA squad up!

Even when threads are "helped" with a glass bead blast, hardening, or heat treatment... there's always stress concentration due to shape. Many times, you've got residual stresses too.

Fatigue testing will find the weak point and initiate a crack. At this point, the crack is its own stress concentration. The material's toughness dictates how much concentration... and it's just a matter of cycles before the part is #rekt.

Thanks for posting the news publicly. There is no failure in R&D... we follow the cycle:
test --> anomaly --> problem definition --> root cause --> corrective action --> re-test

It's only a failure once you've put it in the field, and it seems like you guys are going the extra mile to ensure customer satisfaction.

Thanks for the words of encouragement. I was personally fairly upset as I'm the main person working on this project. When I put it in context though, it really didn't do that bad and would have lasted a few seasons under severe race conditions. We are dealing with a street car though and we want even more longevity built in.

I should also point out we are testing this at around 4 degrees of negative camber. This is to stress it in the absolute worst case we can.

Originally Posted by Calum

Pics or it didn't happen!! I want to see those results, please.

Since we need to prove that it broke.