Monday, October 22, 2012

First vibration test

Good evening!

Last week we performed our first vibration test, where we tested our vacuum chamber, the D-SUB holder and our electronics box with the PCB's. Dummy weights were placed on each PCB to simulate the weight of the actual components we will use. This first test was performed to see that our main structures could withstand the expected vibrations from the rocket. We also wanted to ensure that the PCB's with the dummy weights would not crack due to the vibrations (I guess that the electronics group would have gone mad if we broke their real PCB's during the "real" and final vibration test).

The test was done in four steps:

1. We made a sine sweep at 0.25g to search for eigen-frequencies.

2. We made a sinusodial test at Qualification Level i.e. at 4g.

3. We made a random vibration test at Acceptance Level i.e. at 6 grms.

4. We made an additional sine sweep at 0.25 g to compare to the first one to see if the structures had changed (different or modified eigen frequencies).

The results were good and all parts still seems to be alive. However the two graphs from the sine sweeps was not identical, but we found that one of our dummy weights almost was loose, which probably explains the unequality of the graphs.

Here is the experiment mounted on the shaker before the test

We are also happy to give you a video of the sinusodial test (2)

Unfortunately the quality was deteriorated after the transfer from my phone, but hopefully you can enjoy it anyway.

In the beginning the frequencies are low and you can see the vibrations clearly, but at the end the experiment seems to be stationary. This is due to the high frequencies (ca 2000 Hz), so actually it is oscillating extremely fast, or more exactly; ca 2000 times/sec.


Friday, October 19, 2012


As we promised we will give you a picture of our final layout:

This is all parts attached to our own simplified bulkhead that we use during the testing phase as we wait for the real bulkhead to be delivered.

We performed a first vibration test this week which I will tell you more about, but we save that for another post. Now I have to make some adjustments in the SED.


Sunday, October 14, 2012

Use copper plates, we said.. It´ll be easy, we said...

The copper plates are driving med mad!! (Mad , I tell you MAD!!)  A fairly easy part of the experiment we all assumed but manufacture these all by our selves have been a highly time consuming process. And we just COULD NOT get it right! (stop laughing! :P)  We do however believe that a working procedure have FINALLY been determined and hopefully we´ll be able to produce several approved copper plates to be used in the upcoming test phase! (Hurrah!!)

Let me guide you all through the evolution of the seemingly harmless copper plate (from hell!) :P

Copper plate v1.0 - 1.3: we went from "punched holes" (= the wavy plate) to drilled holes. To drill in a straight line was apparently much harder than predicted but we did manage to drill straight at the end, unfortunately with the holes not located were they were supposed to be!
Failure 1,2 and 3... 
And what happens when the holes are NOT EXACTLY where they are supposed to be? well, the SCREWS don´t fit as planed!
what NOT to look like... 

We figured; hmm maybe I (Maja) was not the best person to drill in these plates so Robert tried...
Robert vs. plate: 0-1
... and Johanna tried...
Johanna vs. plate: 0-2
...AND Johan tried: Johan vs. plate: 0-3
Failure 10, 23 and 101...
UNTIL we finally had a template that wouldn´t betray us! Secured with monkey wrenches, the copper plates are hereby looking according to plan and the experiment tests can proceed without delay! (Hallelujah!)
The Template

Behold! the screws are not in contact with each other and all copper plates now look the same
Thank You all for listening! You´ve been great!

Don´t forget to stay tune for the test phase and remember to tell your friends to like us on facebook! ;) 

Hej då!

Saturday, October 13, 2012

Good evening.

First of all we're sorry for the low blog activity the last weeks. Fortunately we have a "good" reason for that; we've been working really hard and can now see the end of the building phase. Our plan is to be done with the building on Monday and after that enter the testing phase for about one month.

Due to the poor updating about the mechanic parts we will go through them step by step.

The Chambers

Here are our chambers consisting of two hats and two bases. The chambers have been manufactured by a local company

Here is the internal layout of the chambers, with the experimental PCB to the right and the sensor PCB to the left, which we've made ourselves.

Before Monday all PCBs will be installed in the chambers using helicoils and the inlet hole for the pressurized chamber must be sealed.

Electronics Box

This is the electronics box we will use with two test-PCBs for the first vibration test. The electronics box shell was ordered from a company, but we have done all adjustments and the angle braces. Before Monday there are two more d-sub contact outlets that are to be made.

Battery Housing

This is the protective house for our two battery packs which was manufactured by us. The batteries will be well insulated against vibrations and the cold using soft insulation pads between the batteries and the walls.


For lack of good names; this is T-rex. It will work as a link between the electronics box and the chambers for the d-sub cables. This is because we did not have enough space available on the electronics box itself. T-rex was manufactured by us as well.

Bulkhead for testing

Since we will receive the real bulkhead in mid November, we decided to make our own. This is because we will need it during the testing phase. The test bulkhead is a bit simplified compared to the real one, but will hopefully perform equally in the tests. The bulkhead was manufactured by IRF (our neighbours at school). Before Monday all holes will be drilled and tapped.

If you stay updated on the blog I promise to show you the final layout, i.e. all parts attached to the test bulkhead at the beginning of next week.

During the testing phase we promise to have more activity on the blog with pictures, videos etc.

After this quite massive and facts concentrated posts, we hope you are up to date again in terms of the mechanics group's work in Project SOLAR

/The Mechanics Group