Impact attenuator press testing

[prom racing]

Hi, we are a rookie team, and we are trying (among other stuff off course) to test our IA. Because we don't have all the necessary equipment, we have 2 options:
1. scaling and drop test
2. full size press test

In the first situation we don't know hoe to prove mathematically that the results are accurate.
In the second, we cannot find out how to measure peak acceleration.

I have done a small research in the forum, and I have found interesting things, but I still cannot answer my questions.
May anyone of you guys help us out?

Thanks

[prom racing]

Hi, we are a rookie team, and we are trying (among other stuff off course) to test our IA. Because we don't have all the necessary equipment, we have 2 options:
1. scaling and drop test
2. full size press test

In the first situation we don't know hoe to prove mathematically that the results are accurate.
In the second, we cannot find out how to measure peak acceleration.

I have done a small research in the forum, and I have found interesting things, but I still cannot answer my questions.
May anyone of you guys help us out?

Thanks

[Tom W]

1. Really depends on the material, you could try generating a curve depending on how small a scale you have to go to.

2. F=ma

This has been discussed in detail quite recently on the forum so you should be able to find plenty of info in other threads.

[Hub]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by prom racing:
1. scaling and drop test
</div></BLOCKQUOTE>
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> although the Rules do not specify that the tests for the IA Data Report MUST be done on full size test pieces, the Rules Committee intended that to be the case, and Rules B.3.21.3 and B.3.21.4 imply that tests on full size pieces are required. </div></BLOCKQUOTE>
http://www.formulasae.org/foru...%20Test%20Method.doc (http://www.formulasae.org/forums/formula/dispatch.cgi/rules/docProfile/100214/d20081029201720/No/B.3.21.1%20IA%20Test%20Method.doc)

[Bazanaius]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In the first situation we don't know hoe to prove mathematically that the results are accurate. </div></BLOCKQUOTE>

Dimensional Analysis : http://en.wikipedia.org/wiki/Dimensional_analysis

Although bear in mind factors that affect the performance of the IA, which would change with scale.

[Chris Lane]

This is actually a lot easier that it appears to be. Stop thinking too hard!

Try thinking in terms of Work and Pressure.

For testing the actual IA, we talked to a local Load Cell reseller, who ran our prototypes through their press. Just log the load cell and plug the data into excel!

Good Luck

[Adambomb]

For what it's worth, may as well mention what was said in the review on IA test report judging: As far as grading (assuming the report was submitted on time, etc), teams that did dynamic testing started with a B (could go up or down from there), teams that did static/press testing started with a C, and then just downhill from there for teams that did scaled tests (also lots of mention on proving the validity of scaled tests).

Just another thing to take into consideration, we did press testing this year, but don't really want to forfeit a letter next year. Although if you can find someone with a press tester it is quite simple, and much better than not getting it done.

[DG]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Adambomb:
For what it's worth, may as well mention what was said in the review on IA test report judging: </div></BLOCKQUOTE>

Where abouts can this be found?

Cheers

[Adambomb]

Unfortunately I haven't seen it posted anywhere, it was just mentioned in one of the leader meetings in Michigan this year.

[DG]

Ah ok, cheers for the insight anyway.

Rather glad we went the dynamic route now!