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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: 11
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: 818
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: 83
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
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Registered: 11/12/14
Posts: 11
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
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Registered: 01/29/10
Posts: 818
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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#74264 - 12/09/19 11:15 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Tom45 Offline
Member

Registered: 11/12/14
Posts: 11
Loc: Canada
I appreciate every ones answers. However I am still not getting it. I think what you are saying is that each Vector 1, Vector 2, Vector 3 etc. set of values is associated to the corresponding Temp 1, Temp 2, Temp 3 etc.

Is that correct?

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#74266 - 12/10/19 03:47 AM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
danb Offline
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Registered: 04/22/05
Posts: 1321
Loc: ...
Not necessary. May be also external displacements from other sources (e.g. structure displacements or settlement). Only when you construct the load cases you are doing the association. For our convenience we normally define thermal displacement D1 associated with T1 , D2 with T2, but this is not a must.
_________________________
Dan

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#74280 - 12/10/19 11:59 AM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Michael_Fletcher Offline
Member

Registered: 01/29/10
Posts: 818
Loc: Louisiana, US
Let me return your question back to you.

Does T1, T2, T3, etc. directly correlate to P1, P2, P3, etc?

Yes? Maybe? Sometimes? Not at all.

A force is just a displacement, whether it's related to a thermal growth, or a really heavy operator sitting on the pipe.

A distributed load is just a distributed load, whether it's related to seismic load, or a line of heavy operators doing a line dance on the pipe.

You're the one who decides this.

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#74292 - Yesterday at 10:53 PM Re: What is Vector1, Vector2... in the Displacement input? [Re: Tom45]
Richard Ay Offline
Member

Registered: 12/13/99
Posts: 5995
Loc: Houston, Texas, USA
If the word "vector" is the problem, substitute the word "set" or "load condition".

The use of the word "vector" comes from the matrix terminology used to define the solution of [K]{x}={f}. In reality what you have is:

[K][x1, x2, x3, x4,...} = {f1, f2, f3, f3,...}

Here [K] is a matrix and {x1} and {f1} are vectors ( and you define {f1} by building load cases. The components of {f} are the load primitives (T, P, D, F, etc). Since you can have multiples of these items (indicated by T1, T2, P3, F4, etc), we refer to them as vectors also.
_________________________
Regards,
Richard Ay
Hexagon PPM (CAS)
[img] [/img]

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