Mx using different Panel Calculation Model

[HoshangMustafa]

Hi,

I tried two models with different Panel Calculation Model: one with Partial stiffening, and the other Without stiffening. I got two different diagrams for Mx, the former with uniform diagram and the latter with uniform varying diagram. Please find the attached pictures. I wonder why?

[Krzysztof_Wasik]

Hi @HoshangMustafa 

This is the same moment presented in different system of coordinates. Presenting forces and moments for panel cuts in global system of coordinates is the option. If you do not need it for presentation you can switch if off.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Shortly how sign convention for reduced forces for panel cuts work?

[Krzysztof_Wasik]

Hi @HoshangMustafa 

Refer to Reduced results for panels -sign convention

[HoshangMustafa]

Hi @Krzysztof_Wasik 

I noticed in post 58 that "Maps> Myy, Plate and shell results> MYY, and Reduced Results for panels> MRy are all clear (understandable) for me."

What's not clear for me is that when using Results> Panel Cuts> Detailed> Myy, this will be displayed:

I underlined my confusion with blue (Reduced moment (X)= 9.49kNm)

What sign convention is used here?

[Krzysztof_Wasik]

Hi @HoshangMustafa 

Internal forces  integrated along panel cut in the plate are decomposed  and presented in Global system of coordinates. Refer to this help topic

Cuts

and subtopic

Reduction of forces to the center of gravity of a section

(transformed) to global system of coordinates)

[HoshangMustafa]

Hi @Krzysztof_Wasik 

I tried it this way:

What should be summed in last step?

Am I correct?

[Krzysztof_Wasik]

Hi @HoshangMustafa 

I am not sure what you mean, since you pasted screenshot from Help. Acreenshots are correct.

If you have made any calculations for your model please present them . Then I will be abke to verify them.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

I edited my last post.

[Krzysztof_Wasik]

Hi @HoshangMustafa 

Moment from step 1 should be decomposed into statically equivalent moments in global system of coordinates

Step 2 and 3 are not necessary

[HoshangMustafa]

Hi @Krzysztof_Wasik 

You wrote:

Moment from step 1 should be decomposed into statically equivalent moments in global system of coordinates

I'm not aware what do you mean. Can you elaborate more on this?

[Krzysztof_Wasik]

Hi @HoshangMustafa 

We can represent integrated moment (Myy-int) in panel coordinate system as a vector with bending moment value equal to integrated value 9.49 (point 1 )

Then we can present the same vector in arbitrary different coordinate system which in general might be rotated in respect to panel coordinate system (for instance in Global oordinate System). To present vector in different (rotated coordinate system) transformation of coordinate system (in this case rotation) is necessary.

This is standard mathematical operation on vectors. It is explained in details (as an example) in this Youtube tutorial

Coordinate system transformation

In case of  Myy integrated for panel 17 (Myy-int) along selected edge , in transformation formulas, angle 0 should be set since panel local x and y  axes are parallel to X and Y global axes

When in transformation formula rotation angle 0 will be chosen Myy-int (in panel coordinate system) is equivalent to Mx-global (in global coordinate system). Vectors have the same diection and value.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Thanks. It's now clear.

Another question came into mind:

Does Qyy diagram in FE model

correspond to this diagram in Partial stiffening model:

[HoshangMustafa]

I mean if I want to know how much load is transferred to beam 9 from case DL2 using FE model, can I use Qyy?

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Any help would be highly appreciated.

[HoshangMustafa]

I mean if I want to know how much load is transferred to beam 9 from case DL2 using FE model, can I use Qyy?

Does Qyy diagram in FE model correspond (is equivalent)

to this diagram in Partial stiffening model:

[HoshangMustafa]

Hi @Krzysztof_Wasik 

• Should I give up my last inquiry?
• Using fine meshes (I tried 0.02m), it seems the entire Myy for panel 17 will be transferred as Mx in bar 9.
• Why does moment Myy in Panel Cut A-A2 appear as if it wasn’t transferred to bar 18 (it seems as bar 18 doesn’t support the panels)? I tried a 300x1500mm section for bar 18 and some negative bending moment appeared on bar 18 (seemed as if bar 18 would support the panels).

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Hi @Krzysztof_Wasik 

• Should I give up my last inquiry (check message 75)?
• Using fine meshes (I tried 0.02m), it seems the entire Myy for panel 17 will be transferred as Mx in bar 9 (check message 12).
• Why does moment Myy in Panel Cut A-A2 appear as if it wasn’t transferred to bar 18 (it seems as bar 18 doesn’t support the panels)? I tried a 300x1500mm section for bar 18 and some negative bending moment appeared on bar 18 (seemed as if bar 18 would support the panels).

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Aren't my inquiries reasonable?

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Can you respond to my queries?

[Krzysztof_Wasik]

Hi @HoshangMustafa 

I have impresion that this thread will be not usefull for other Robot users. There are too many mails in It regarding different problems. Could you ask unaswered question in new Forum thread.