Hi at all.

Found a little bit time this morning.
My students are busy (I work as trainer for Solidworks) and I am not at home where we have some visitors over the Eastertime.

Here is an overlook about the workflow with MoI and Z88.

1. Drawing the framestructure in MoI (closer description will follow)
2. Editing of the z88i1.txt file (wirh the help of Max´s script; example next time) and save it in Z88
- we can see now the structure in Z88 with the labeling of the knots and the struts -
3. for different loads we make different files z88i2.txt (needs also a description)
4. we calculate every load in its own process
5. from Z88 we will get every time a file named z88o3.txt (here we have the tension and compression loads for the struts between the knots)
6. we take an excel sheet and put the inhold of the z88o3.txt in a column. After all calculations we have horizontaly all loadcases and verticaly
all struts. With an excel funtion we filter horizontaly all worst loads of tension and compression from our struts (max/min funktion)
7. As essence from all calculations we make a second excel sheet.
-Number of strut- startpoint (knot)- endpoint (knot)- true length- tension load- compression load- wall thickness- weight of strut
8. Now we calculate the outer diameter of our tubes (for this I have a little software in "dos" I would like to spend).
If the result shows Ø 14,58 we take Ø15 from our hardware dealer for example
9. Now we can draw the real structure

Every step will have later it´s own little tutorial with pictures.

In the first moment it seems a little bit complicated. But sometimes we have more then 200 struts an maybe 80 ore more knots in a 3D structure and
I had sometimes more then 30 loadcases. To calculate this needs many weeks. (If it is possible).

At next I try to test the script from Max.

Have a good time

Hans

maybe a missunderstood-

>some weeks of calculation>
with a handcalculator and a pencil

Hans

Hallo Hans and Max,

I look forward to taking a closer look when I'm home next week.

Cheers,
Hamish

Hi Max, Michael, Hamish an all

Max, your script is wonderfull!!

We need only a little bit finetuning to make it perfect.

Michael, thank you for substituting.

Hamish, thank you too.

Now to the script:

Z88 calculate 2D structures and 3D structures.
The different is only a "2" instead of a "3" in the line of the point coordinates
and the Type of the line (strut) is "9" for 2D- and "4" for 3D structures.

The input files in z88 have no dimensions.
We can take it for yards or feet or inch or mm
The load may be Newton or pound or tons.

With mm and Newton like I prefer, decimals for length or load are not necessary.
If the projekt is a big one (the Eiffel Tower for example) the result could be more
exact with one or two decimals in the length of the struts because the dimensions in the background are bigger.

Now we come to the mistakes of my explainings!

Max, you write

== endpoints ==
number of strut startpoint endpoint
1 1 2
2 3 2
...............................................

We need:

number of strut type of strut

startpoint endpoint

1 4
1 2
2 4
3 2
3 4
3 4
4 4
3 1
............

Can we have a little command window with the script?

like this:
------------
2D 3D

decimals 0;1;2;3

OK
-------------------
If we choose [2D] we will have a 2 in the line of point coordinates and a 9 as type of the struts
and with [3D] a 3 and a 4

After OK we can paste it like bevor.

With every new projekt we have to write a headline and a feetline and into a few seconds the z88i1.txt file
is ready.

At the 16. of April I have a meeting with the people of the Bayreuth University at the Hannover Fair.
I know that they look for a software that fit to her Z88. Some people asked for a good and not so expencive cad-programm.
Your script helps me to construct my little sportsplane, helps a lot of engeneers to build everything from bridges to framestructures
for satelites and I hope it helps Michael to give some more licenses into the world.

Happy Eastertime

Hans

Hi Hans,

Could you post here an examples of those Z88i1.txt files? With headers, footers etc..
It will help me to create a proper structure exactly as you want.

Hi Max,

I will prepare it this afternoon.

Thanks
Hans

I downloaded Z88AuroraV2, for Windows7.
The pdf file "theoryguide" shows the "GENERAL STRUCTURE DATA Z88I1.TXT" starting on page 54, and much more... Z88I2.TXT, Z88I5.TXT...file checker Z88VRY.

The explanation for the KFlag for cylindrical coordinates versus Cartesian coordinates seemed contradictory?

There is also DXF CONVERTER Z88X which is supposed to convert dxf r12 files to the 3 .TXT files.
There is an STL CONVERTER, Z88GEOCON...
Perhaps a .js converter could be checked with the above two converters?

(I've never used Z88)

- Brian

How load a file inside Z88 ? :)
I suppose it works only with DXF format ?

PS You don't like this free one ? :)
http://geuz.org/gmsh/ reload IGES, Step from moi ;)
http://geuz.org/gmsh/screencasts/
+ http://www.calculix.de/

or even Salome + Netgen http://www.salome-platform.org/ + http://www.hpfem.jku.at/netgen/index.html

Hi Max and all.

Here is the example of z88i1.txt.
It is the input file of the "Kranträger".

Pilou: In the past I allways worked with the open source version Z88 10.
Please copy the file in the main folder.

To work with Z88 is not a simple process. Max´s script will make it much more easy.

Z88 I like because it calculate the forces between the knots. Most importend if we build a "new Eiffel Tower" is
to construct the struts resistant against the bending loads. (Euler cases)
Colourfull pictures of "von Mises tension" do not help. Under load a frame structure will be destroyed when the
struts bend out.

Please stay patient. We will see what a powerfull tool MoI is not only in design also in development and engeneering.

Happy and optimistic Eastertime

Hans

Thx: take your time we will be very patient! ;)

NOTE: I should have opened the Informationen file in a proper word processor. :-( It comes pre-parsed.

 

I did a Parse of the Kranträger file in an attempt to understand it, and reconcile it with theoryguidePDF.
A few differences and questions resulted.

// Header is the first group, and has seven entries. (Versus 5 ???)
// #Dimensions = 3
// #Knots (or #Nodes) = 26
// #Struts (or #Elements) = 72
// DegreesOfFreedom = 60 (3 times 26 = 78, not 60 ???) (Maybe because structure is open, not closed?)
// LawOfE-modulus (What is this?)
// Flag (KFLAG is 0 for cartesian coordinates)
// Flag (Why are there two flags?)

3 26 72 60 1 0 0
========================================

// The second group has entries for each of the 26 KnotNodes.
// Knot#, DegreesFreedomThisNnot, Xcoord, Ycoord, Zcoord.
1 3 20 20 0
2 3 0 0 0
3 3 10 10 25
4 3 0 20 0
5 3 20 0 0
6 3 30 10 25
7 3 40 20 0
8 3 40 0 0
9 3 50 10 25
10 3 60 20 0
11 3 60 0 0
12 3 70 10 25
13 3 80 20 0
14 3 80 0 0
15 3 90 10 25
16 3 100 20 0
17 3 100 0 0
18 3 110 10 25
19 3 120 20 0
20 3 120 0 0
21 3 130 10 25
22 3 140 20 0
23 3 140 0 0
24 3 150 10 25
25 3 160 20 0
26 3 160 0 0
========================================

// The third group is explained on page 55 of theoryguidePDF.
// not sure if this is the correct parse.
1 4
1 2

2 4
3 2

3 4
3 4

4 4
3 1
etcetera (Did not parse the rest of the file)

- Brian

Hi Hans

Check the new version.
At the moment it supports 3D knots only.

I have the same question about DegreesOfFreedom. Why 60?

If the first 3 nodes, and the last 3 nodes are fixed, or boundary condition, maybe they do not count?
3 X (26 - 6) = 60.
(There is so much I do not know about FEA :-)
There is supposed to be a book...

- Brian

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