In OpenSees Command Language Manual says "The x-axis is the axis connecting the two element nodes;the y-and z-axes are then defined using a vector that lies on a plane parallel to the local x-z plane--vecxz.The y-axis is defined by taking the cross product of the x-axis and the vecxz vector."
But I can't understand what's the meaning of this sentence even look at the pictures .
if nodal coordinates of a beam-column element are nodei(5,4,-3),nodej(-2,6,2), respectively, how to define the following three parameters, $vecxzX $vecxzY $vecxzZ?
many thanks for any help.
z
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|
|
|
|
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| * j(-2,6,2)
| *______________________y
/ *
/ * pipe
/ *
/ * i(5,4,-3)
/
/
/
/
x
Sectional properties of pipe(beam-column) element considered here is as follows: diameter is 120mm, thickness 5mm.
how to define the following three parameters, $vecxzX $vecxzY $vecxzZ?
Dear fmk, help!!!
Moderators: silvia, selimgunay, Moderators
let's try again.
1. you need to understand the right hand rule.
[url]
http://en.wikipedia.org/wiki/Right-hand_rule
[/url]
2. the x axis (your thumb) points along the axis of the element, iNode to jNode.
3. you need to define a plane, the x-z plane. This is the plane in which the x axis (your middle finger) lies.
from basic coordinate geometry you need 2 vectors to define a plane (the x axis is one, you need to provide a z vector).
4. the y axis is the cross-product of the x axis and the z vector supplied. if you play with your finger or a cardboard cut out you will see that no matter what the z vector you supplied to define the x-z plane is, the y axis remains constant.
5. YOU NEED TO SIMPLY PROVIDE THE Z VECTOR.
Either use your hand or a cardboard cut-out.
you need to figure this out for yourself. if you cannot understand this you will never be able to figure out what the results mean. and i am not going to give you an answer for this and have you come back again.
1. you need to understand the right hand rule.
[url]
http://en.wikipedia.org/wiki/Right-hand_rule
[/url]
2. the x axis (your thumb) points along the axis of the element, iNode to jNode.
3. you need to define a plane, the x-z plane. This is the plane in which the x axis (your middle finger) lies.
from basic coordinate geometry you need 2 vectors to define a plane (the x axis is one, you need to provide a z vector).
4. the y axis is the cross-product of the x axis and the z vector supplied. if you play with your finger or a cardboard cut out you will see that no matter what the z vector you supplied to define the x-z plane is, the y axis remains constant.
5. YOU NEED TO SIMPLY PROVIDE THE Z VECTOR.
Either use your hand or a cardboard cut-out.
you need to figure this out for yourself. if you cannot understand this you will never be able to figure out what the results mean. and i am not going to give you an answer for this and have you come back again.
Last edited by fmk on Wed Apr 14, 2010 9:56 am, edited 1 time in total.