shell91 and material attribution

[Dmaz]

Hello everyone, I am using shell91 to layer a composite material.
the various layers of the laminate are composed of two materials and when I go to define the specific real costants epr each layer the materialil, the orientation and the thickness. It's okay.
However, when I do "mesh attributes" to say which real costant to use in different areas of the model in addition to the "real costant set number" I'm required the "material number". what should I specify here since the laminate is effective consisting of the two materials already specified in the real costants and not by one that I should specify here?
Thank you.
dmaz

 

[volaff]

you should specify the second material in prepprocessor---material propos---material models and specify the type of material (orthropic in the case of a composite usually)

 

[Dmaz]

yes in the preprocessor both orthotropic materials are specified.
later at the time of assigning them to create laminate in real costant I can say that the first layer is made with material 1 and x orientation and the second layer with material 2 and orientation y.
However in the "mesh attributes" of the area I go to meshare with the shell91 I have to choose the "real costant set number" (which within if it has rightly specified the two materials) and choose the material number again. but it seems to me a countersensitivity because if I choose matarial 1 that end the layers of material 2?

 

[volaff]

the correct procedure to follow should be:

1. choose the shell91
2.definite the two materials (and,coefficient of polka dots and other characteristics of orthotropic material)
3. assign real constants:

♪

layer 1

layer 2

ps: I do not understand what centers mesh with the material... .

 

[Dmaz]

Thank you, this is the procedure that you usually use for a simple problem.
in my problem instead I have to deal with a complex object, modeled all in shell91 divided into many areas and each area has a different real costant (i.e. made by a different laminate, the real costant I use are 10 in all) in which they come into play up to 5 different materials. before going to meshare, with the command "mesh attributes" go to assign to each area its element, its real costant and its material and then meshi everything. so you have a unique mesh of shell elements whose features however change depending on the area of belonging.
But I found this inconguence on materials that I can't explain. .

 

[volaff]

Um... I don't know what to say then.. That sounds weird.

 

[stefano.garbin]

dmaz, use shell181 and sections. so you get rid of real constants, define well the layup of the sections also with different materials and proceed as a train.
Ansys guide, chapter 13.1, "modeling composites".

 

[Dmaz]

Okay thank you now I'll give you an eye!
but then in fact using shell91 with the command "mesh attributes" I would reassign the material that I had defined in pre-cendence in the "real costants" by uniforming it in all layers?

 

[turbin87]

hello to all
I am a student in mechanical engineering and I would like to understand the difference between a layered solid, layered shell and a solid shell, since I have to do a thesis in composite material and the prof told me first of all to learn how to use these three elements.
I would be very grateful if you give me some concrete examples

 

[stefano.garbin]

rtfm
solid = element generated during the meshatura of a solid. unless otherwise specified the coordinate system of the element is parallel to the global one
layered solid = as above, but you can define layers oriented according to the element z axis. attention that orienting elements so is a long and complex operation.
solid shell = element generated during the meshatura of type "sweep" (it was explicitly told to the meshatore to use it) in which the z axis is normally oriented orthogonally to the beginning and fine sweep surfaces.
shell = element generated by meshando the surfaces. The z axis is normal to the surfaces.

 

[turbin87]

Thank you very much for your explanation. He made me clear
doubt. Excuse me if I take advantage of your kindness but I would like
clarify another doubt about it. I want to know what you mean
for sandwiches when you have to make a volume
made of composite material using the layered shell. as far as
about layered solid I wanted to know if I understood the concept of layers well.
i.e. assuming that the solid element is a cube, if I use the layered solid
then this cube can do it with n layers of square foils of different material. Right?

 

[turbin87]

Hello guys about shell 91 I modeled a chair in composite material and
the professor assigned me the task of finding interlaminary tensions between the lamina adjacent to the soul and the soul of the sandwich I created using solid95. Unfortunately he wants to
that I use these two elements instead of shell281 and solid186. So my problem is that when I plotted the interlaminary tensions related to the first lamina adjacent to solid95, finishing the emission table relative to the interlaminar tension of the lower surface of the foil, I do not plot anything giving me an all-grey color. The strange thing is that for all other lamines it gives me the values of interlaminary tensions. So I can't get over it. Please, if someone is an expert on these two elements, help me:-(.