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#73808 - 09/20/19 12:00 PM What is Vector1, Vector2... in the Displacement input?
Tom45 Offline
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Registered: 11/12/14
Posts: 25
Loc: Canada
What does the Vector1, Vector2, ... Vector 9 represent in the Displacement input screen?

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#73809 - 09/20/19 02:41 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Michael_Fletcher Offline
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Registered: 01/29/10
Posts: 938
Loc: Louisiana, US
You can specify the displacement of a given node on a given element up to 9 different ways. Then you specify when those displacements apply in the load case editor as D1, D2... D9.

Same applies to point loads, F1... F9 and distributed loads, U1... U9.

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#73818 - 09/23/19 10:29 AM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
anubis512 Offline
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Registered: 08/24/18
Posts: 107
Loc: USA
To add onto the answer above, these are external displacements your piping is seeing in the directions you defined in the vector.

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#74165 - 11/14/19 06:46 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Tom45 Offline
Member

Registered: 11/12/14
Posts: 25
Loc: Canada
I understand displacements but why call it Vector 1, Vector2 etc.

Is there some significance that I am missing as to why it is called that??

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#74166 - 11/14/19 06:57 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Faizal K Offline
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Registered: 07/21/08
Posts: 159
Loc: USA/Malaysia
CAESAR II is just allowing you to define up to 9 sets (vectors) of displacements.

Let's say your line is tied to a much larger header having multiple operating modes. Say case 1, the header goes +1" in the X direction. Case 2 it goes to -1" X and +1" Z. You can define D1 = {1,0,0,0,0,0}*, D2 = {-1,0,1,0,0,0}*. D1 is displacement vector 1, D2 = displacement vector 2 etc.

In your load case setup, you can even combine them too if you want.



*{DX, DY, DZ, RX, RY, RZ}

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#74167 - 11/14/19 06:59 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Faizal K Offline
Member

Registered: 07/21/08
Posts: 159
Loc: USA/Malaysia
also, displacement is a vector since you have magnitude and direction. just like the force input.

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#74178 - 11/15/19 10:01 AM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Michael_Fletcher Offline
Member

Registered: 01/29/10
Posts: 938
Loc: Louisiana, US
An additional note. You might be tempted to say D1 = {1,0,0,0,0,0} and D2 = {0,0,1,0,0,0} thus D1+D2 = {1,0,1,0,0,0} but this would be incorrect.

I think CAESAR averages the 2? D1+D2 = {0.5, 0, 0.5, 0, 0, 0}.

(Or it could also do SRSS - I just don't remember.)

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#75380 - 01/28/21 05:43 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Tom45 Offline
Member

Registered: 11/12/14
Posts: 25
Loc: Canada
So Vector1 corresponds with T1, Vector2 corresponds with T2 and so on. Is that correct?

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#75382 - 01/28/21 10:23 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Richard Ay Offline
Member

Registered: 12/13/99
Posts: 6097
Loc: Houston, Texas, USA
Tom45,

The terminology associated with matrix solutions (i.e. [K]{x}={f}) typically refers to the stiffness matrix [K], the load vector {f}, and the displacement vector {x}.

When you have multiple load cases, you have multiple load vectors, i.e. {f1, f2, f3, ...}, which correspond to multiple displacement vectors i.e. {x1, x2, x3, ...}. Now, what you put in each load vector is up to you. However, to keep ones sanity most people would put T1, P1, D1, F1, U1 and so forth in "f1". Then T2, P2 and so forth in "f2", and so on. Of course this idea falls apart in more complex systems, especially when occasional loads are considered.

CAESAR II doesn't care, the software does not force any particular convention. There is no rule that says T1 must go along with P1 - that is determined by your system. This is why it is a good idea to use the "load case name" option.
_________________________
Regards,
Richard Ay - Consultant

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#75385 - 01/31/21 05:46 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Michael_Fletcher Offline
Member

Registered: 01/29/10
Posts: 938
Loc: Louisiana, US
When automatically specifying load cases, CAESAR will often assume correlation between P1, T1, etc. However, that's just a point of convenience if you set it up that way.

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