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Jupyter Notebook

Posted: Sat Jan 02, 2021 10:50 pm
by pmbrunelle
This is a tool I use occasionally for some more complex calculations, when I need something more fancy than Excel.

My work colleague introduced me to Jupyter Notebook.

An "online server" runs the Python kernel, and presents to you (via a web browser) the Notebook interface. Typically both sides can run on the same machine, but this is not obligatory. I'm running this on Windows 10, but other platforms work too.

You can type code in cells, the code is then executed when you click Run, and then results can be printed to the next cell below.

In this environment, libraries such as numpy are available to facilitate scientific calculations.

This is all free of course, which is a good thing. I know some guys who learned Matlab, and now they are addicted to a high-dollar drug... that's kind of like my unfortunate relationship with SolidWorks.

I'm not really a Python guy, but there are many examples and tutorials available on the Internet if you get stuck.

Here I am doing a simulation. I am considering drilling my brake rotors with holes drilled between the vanes. 37 vanes = 37 holes. 37 is a prime number, so I cannot repeat a hole pattern to ensure balance (that would be too easy).

So up top, I write some code; it's randomly rearranging hole positions, and finding the resultant centre of mass of the holes:
Screenshot.png
Screenshot.png (62.94 KiB) Viewed 1979 times
Here is a result obtained after all afternoon trying things:
Scrolled down.png
Scrolled down.png (54.98 KiB) Viewed 1979 times
So that's like having an imbalance of a drilled hole 0.002 mm off-centre.
It took 159323763 iterations to find this result.

Re: Jupyter Notebook

Posted: Sat Jan 02, 2021 11:20 pm
by ericjon262
since I got my 3d printer, I've been more and more interested in learning coding processes, I need more hours in the day!

Re: Jupyter Notebook

Posted: Sun Jan 03, 2021 9:47 am
by The Dark Side of Will
Code is the new Latin. Every educated person should know some.

Re: Jupyter Notebook

Posted: Sun Jan 03, 2021 9:54 am
by The Dark Side of Will
And the Jupyter notebook looks like a fun product. Free is always the right price.

Why wouldn't 37 holes at the same radius balance? Are you worried about that introducing stress concentrations?

Re: Jupyter Notebook

Posted: Sun Jan 03, 2021 12:44 pm
by pmbrunelle
37 holes at the same radius would balance, but I have another constraint that disqualifies that solution for brake use.

Between some innermost and outermost radius extremes (limited by distance to edge for cracking), I want the holes to be uniformly distributed along the radius.

For example:

hole 0, r = 100 mm
hole 1, r = 101 mm
hole 2, r = 102 mm
hole 3, r = 103 mm
...
...
hole 35, r = 135 mm
hole 36, r = 136 mm

The idea is that all radii on the brake pads are equally wiped/scraped.

Here is a case where the holes are clustered on certain radii:
https://ebcbrakes.com/articles/dangerou ... ed-rotors/
Circular grooves, not very uniform wear...

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Stress-wise, I'm not worried for street driving, as I've had drilled rotors to some extent since my first car.
Falcon_ca has a set I did, and they've held up over the years:
https://www.fieromontreal.com/index.php ... 0#msg12730

For this new Fiero project, I may want to take it occasionally to a track, so I cannot fall back on my street experience with drilled rotors to say it will be OK with track duty.

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Slotting would require 8 mill setups to do four rotors, with a ball mill. The cutting for each setup would be done pretty quickly.
Drilling would require 4 mill setups (drilling on one side all the way through to the other). Each setup would require a tool change from centre drill to drill bit.

Either of these plans seems a bit long for a "stay at work after-hours" type of scenario, unless I do it in two evenings.

I'm not really sure what I want to do with my brake rotors; for now I'm just enjoying the "fun with code" brain-teaser.