the hunt for an easier way …

[WebPilot]

Well, has anyone gotten this program to work up to this point?

[PyroJoe]

Getting warning flags and anit-virus blocking stuff for now, will try with other machine this evening. Apologize for not trying it sooner, has been a busy weekend.
Joe

[Rossco]

Code works. Looking further into the rest.

Rossco

Ah,

Edits:
1) in^4 ...

[WebPilot]

Joe, I hope you PM Rossco if you cannot resolve this yourself.

I am little help when it comes to resolving µSoft issues, but I would suggest trying another browser instead of Internet Explorer (e.g. Firefox, Opera, etc.) for this project. That way, you can still work on your normal machine.

[WebPilot]

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This program requires 5 inputs from the user:

1. what is the length of CAD rectangle 1?
2. what is the width of CAD rectangle 1?
3. what is the thickness of petal valve?
4. What is the longitudinal distance to CM of a side lobe?
5. What is the area of one side lobe?

[WebPilot]

The answer to the first two questions can be answered with a drawing.

Here's mine again:

Figure 1. CAD drawing of DynaJet petal valve

[WebPilot]

The thickness, 0.006 in, is given on the CURTIS DYNAFOG® Ltd plan.

[WebPilot]

The answer to question #4 can be determined by using what I had calculated
& posted earlier, namely the value for the yCM co-ordinate.

It cannot be used 'as is' since that distance is relative to the origin, 0, and not
from point, ß, as required. So, subtract 0.625/2 from it before using.



NOTE: these values were not in error; the ones on my spreadsheet
calc were.

[WebPilot]

Finally, a value for the area of one side lobe, 0.0567 in², is provided on the last ' tally' sheet.

[WebPilot]

You should now get something resembling this in your browser window:

[WebPilot]

Returning to the work I did in my Mode 1/0 thread, you will find this image:



where I found the converged, fundamental frequency for a dynajet petal
valve to be 247.0 Hz.

[WebPilot]

So, the % deviation using my approximate method with the number obtained using the finite element method is a mere



Not shabby, eh?

[WebPilot]

The previous is a 'proof of concept', and it works. While I was writing code to eliminate the need for a spreadsheet, I began to wonder if a Cad program was absolutely required. It's not.

Two evenings ago and anxious to use bc, I started writing a script to determine the frequency of a dynajet petal valve.

The algorithm requires four dimensions, taken from the original plan of the engine. Additionally, it needs two material properties. These are for steel in this case.

The algorithm is not interactive. The required inputs are hard coded in the script, but can be quickly changed with an editor.

I finished the code yesterday evening. Here is a session log from a terminal window.



The code runs and is accurate.

[WebPilot]

First, I'll use this code to investigate how the pv's fundamental frequency varies with thickness.

[WebPilot]

Here, the geometry of a dynaJet petal valve is kept constant, but the thickness is varied.

The result is frequency varies linearly with thickness or

f = a × t + b

values for 'a' and 'b' are determined above.