Hi at all.

Sorry, my mistake.

26 x 3 = 78

I had a handbook with an example beside and wrote the wrong number.

bemfarmer:

Z88 take about 24 different type of elements. Some need special flags - some not.
For my structures I used only Type 4 and Type 9.
As a user I have no clue wy it has to be a 0. It´s inside the programm.

E-law - is the direkt translation of "E-Gesetz".
It is the same as E-Modulus.


Max: Thank you. I write a little bit later again.

Hans

Hi Max,

for 3D- framestructures the script is PERFEKT !!!!

Thank you !!!!

At home I have some drawings of antik aircrafts.
There will be a funny example for a tutorial.
Now I go to choose one of it.
Next info at tuesday evening.

Hans

Hi Hans
nice to hear it. :)
Please share the results. That interests me very much.

If everything works good, I'll make interface and 2D support next week.

Hi Max.

Today I prepaired a structure of an old little racing biplane.
There are some pictures to scan.
Tomorrow in the evening after work we start with the first part of the tutorial.

Bye and thank you again.
Hans

Hi Hans and Max,

Max, I'm really pleased you ended up writing this script in its entirety. You've achieved much more, and most likely better quality code, than I ever could have in the same time. Additionally, all us novice script writers get another fine example to reference - THANK YOU! :)

Hans, I really look forward to following your FEA tutorials and generally learning more about FEA. I'll inform the UK Light Aircraft Association, (the CAA delegated authority for amateur-built aircraft in the UK) engineering department after you post your first tutorial. I'm sure the LAA chief engineer will be very interested in this, certainly as an educational tool and hopefully as a useful tool for aircraft design analysis.

Cheers,
Hamish

Hi Max, Hamish and all.

Here we start with the first part of my little tutorial.

Pilou: you asked for more passenger places. Hope you like the little plane made by a friend from Chatteau Briand airfield.
You remember? " 4 people and an basket full of eggs"

The little Biplane Racer construction now has an age of 90 years and shut been full reconstructed.

Attention please!!!!
The example of workflow we will see in the next days is not for practical use. All loads that will be setted are "over the thumb" calculated
to save a lot of time.

The MoI files show how to draw a structure and and the racer structure we only need to place the loads for the fuselage.

Z88i1.txt was made in five seconds. The true lengths of all struts have been saved in an other file for later using.
We see a picture of the structure opened in Z88 with all node numbers. Now we have to prepaire the z88i2.txt files
to calculate step by step all loads. It needs a little time and I can do this over the next days.

Next time we see how to make a load file and to build a data structure with Excel.

Hans

Hi Hans,

This looks like it should develop into a very useful tutorial: complex enough to prove the value of using a tool like z88, but not so mind-blowingly complex that it puts people off learning more about structural analysis. Thank you so much - I know it takes some time to prepare these kind of lessons. I look forward to reading the next step!

You say the preparation of z88i2.txt will take some time. Perhaps not on this occasion, but is the preparation process something that could also benefit from being automated by way of a text-editing script?

- Hamish

The Louis Blériot's plane ;)

Hi Hamish.

To create a loadfile is a process that must be done manualy step by step.
Description follows.

Hans

Hi at all.

I´m sitting in my classroom, my students are working and there is a little bit time
to explaine the z88i2.txt file to handle the loads.

The file consist of more ore less textlines with numbers.
every line of numbers is a subcase named in german: RBD = Randbedingung

9 < there is only one number in this line to count the RBD>

Now we fix a node:
5 1 2 0

5 < number of node>
1 < x-axis>
2 < way>
0 < no movement>

5 2 2 0 < the same as above in y-axis>
5 3 2 0 < z-axis>

If we set a way like 5 2 2 8 then we will have loads in the strukture.

We fix an other node:
9 1 2 0
9 2 2 0
9 3 2 0

We put a load at node number 18 in negativ direction
18 3 1 -8500

18 < number of node>
3 < z-axis>
1 < we have a load>
8500 < if take the positiv direction>

The third node may slide in x-axis because that the structure will bend.
It is only fixed in 2 axis.
27 2 2 0
27 3 2 0

It is importend that the RBD follows the numbers of the nodes.
123458 is o.k.
128534 is not o.k.

The result is now.
....................................
9
5 1 2 0
5 2 2 0
5 3 2 0
9 1 2 0
9 2 2 0
9 3 2 0
18 3 1 -8500
27 2 2 0
27 3 2 0
.....................................

z88i2.txt we save in the main folder together with z88i1.txt and run the calculation.

Now we start our "over the thumb" calculation for the loads and searching the right nodes to set it in the rigth
directions.

Bye for now
Hans

Hi Hans,

I see why it takes some time to generate z88i2.txt. I still wonder if an interactive script might be useful for creating z88i2.txt?

I envisage this second script would either step through the nodes saved to z88i1.txt - or original script is modified to generate z88i1.txt and z88i2.txt concurrently - and allow the user to enter Randbedingung (RBD) [English = constraint] conditions via a GUI.

Ideally the script would highlight the node for which RBD info is required to be entered. It might need a fwd/back/select-node interface in case the user enters incorrect RBD and wants to correct/modify it after the script has stepped to the next node.

Sometimes it's nice to have a helper script, though other times they can be more hindrance than assistance, so I fully understand if you say my envisaged second script would be less than helpful - or simply too much work. What do you think Hans, Max?

- Hamish

Hello to all,
very interesting thread and work! By the way - Randbedingung - typically Boundary condition:-)(Forces, pressure, fixtures, constraint displacements ....)

A nice day to all
Karsten

p.s.: pilou - the pilot has a french curve;-)

Hi Hamish, Karsten and all.

Hamish: this weekend I will prepaire all loads. Then we see much bigger z88i2.txt files. May be this helps you to decide

you like it or not to make a special skript for the loadfiles.

Helpfull woud be if the nodenumbers are visibel in MoI. In MoI they are more easy to select.

An other problem is my bad english. Now I visited "LEO" in the net. Some therms will be more exact in the future.

If you ore somebody else like to translate my lyrics for better reading feel free to do it like you want.


Karsten: Thank you for your positive response.

Happy days

Hans

Hi Max, Hamish and all.

Today I was trouble shooting.
Max >
There is a filechecker in Z88. Something was wrong with z88i1.txt.
In my old handbook where in line 1: two flags with 0
Now it should be: three flags with 0.
Please don´t ask me why.
Sorry Max!

Hamish >
Next problem was with z88i2.txt.
Not only the nodes has to follow 1234. Also the boundary conditions
has to follow xyz.

For example:
50 3 1 4000
50 1 1 -2500
this is wrong
shut be
50 1 1 -2500
50 3 1 4000

Then z88 tells me that my structure is not corect with its static.
Could not find my mistace. It needs to much time for searching
so I will make tomorrow a more simple construktion where I can
test my 28 condition file and more with.

Good news are that with Max´s script we are also able to use the
two types of bar. Number 2 and 13.
Calculating of straigth spars are possible with it.
Helpfull for this would be a script that gives the moment of inertia from cross sections.
In MoI we draw a face. Some cad systems has it.

One year ago somebody from the Uni Bayreuth told me the make a new software that handle the other direction
of FEM. You set the load and the anotations and the software forms the part.
I believe it will be also freeware.

Bye till tomorrow
Hans

Hi at all.

Today I had to made many tests. Z88i1.txt was o.k. With three times a zero at line 1.
Z88i2.txt was also o.k. There is a filechecker in z88 for proving.

When I start to run the calculation z88 allways told me that my static is not corect.
So I made a more and more simple structure step by step. Five or six times. Allways the same problem.

Then I made a simple cranestructure. > Everything was running for the first time.<

If we look at the crane drawing we see that the nodes have growing numbers along the x-axis.
This depends on the way the drawing was made. With Array in one direction.
The Biplane drawing is in its nature a more chaotic system.
We see this how the node numbers are placed.

In the old way with dxf files we had to draw twice. First the chaotic (normal) way to create the structure.
Then from one end along x to the other end allways left around line after line. The FEM way.

Max> may it be possible to choose the points with [ get points] and then to click all the lines in the rigth order bevor
we start the script?
And then the scipt read it on the same way?

I´m shure that will help.

Now we have: the simple structure, z88i1.txt from it, z88i2.txt. and z88o3.txt.
Z88o3.txt shows all the tensions in the struts between the nodes.

The tools I used: MoI,
JFE -JensFileEditor- a free english version is in the net.
It opens Max´s script direct in in the rigth way.
A capture programm to make the plotting pictures.
Word for its search and replacement funktion.
We need it for editing z88o3.txt.

search ^p^p
replace it with ^p

It makes z88o3.txt shorter.

then we use JFE to marking vertical all the +/- loads of the struts and save them in a new file.
Later we set every content (loadcase) in an Excel sheet.
We also make a folder structur for every loadcase.
When all the little problems are solved I have to make a summary of the calculation process.

This is my weekend result.

Your optimistic Hans

Hi Max,

a new idea to handle the drawings could be to draw first the structure in the "chaotic way", then set the points more directed and after this
to delete the lines step by step and draw the structure again in a FEM mode.
It needs only a few minutes.
This evening I make test and give you the result.

Hans

Hi Hans
Sorry, I was busy last days. Today I'll read all your messages and write answer.

Hi Max, Hamish and all.

It seems for me that MoI gives the elements back to the script in the same sequence
like they have been drawn.
So I used the new procedure of drawing.
First I was drawing a simple structure in the most possible chaotic way.
Then I placed the points left around the frames along X.
I deleted two or three lines again and again and drafted they new in the same manner (left around).
Every time I chanched the stile to red.
After finishing the structure I used Max´s script.
The result was o.k. The structure was much more aligned.

At next I try more complex frames.

Good night for now
Hans

Hi Max, Hamish and all.

Sorry, but the last two weeks I didn´t have enought time.
After the first of May the whole situation will be better. Than I go into my retirement.
Last thursday I had a good conversation with the guys from the Bayreuth University
at the Hannover Fair.

They want to help us with our files and there is a reason to do that.
At the beginning of our projekt the tests have been made with the version I have allways used. Z88100.
You know it was partly successfull. I have installed the new version Z88OS14 and it can not read z88i1.txt from your script.
I don´t know why.
You can see the result. Bevor few minutes we (uni bayreuth and me) had a conversation about
the problem. They are optimistic that we together find a way to connect MoI and Z88.
But it seems that we need a little bit more time.

Max, please explain me how your script read the information from MoI.
Now I send some files to Bayreuth. Then you will have all information from me.

The hopefully Hans
(biggest fan of nodes)