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Subject: Re: Intersection of two plates
Author: Jan Christian Anker
Date: 1999-01-15 08:54:00

This is too difficult for me, so I have to ask some silly
questions:

1) Do I understand it correctly that there one wall
with thickness 18 mm?
2) Is there only one stiffener per 300 mm?
3) Is the stiffener welded to the wall?

If the answer to items 1 - 3 above is 3 X "yes", then
you could do the modeling using shell elements
without any constraint equations (Jan Christian's
first rule of modeling would be "never use constraint
equations"). The elements would be at the
centerlines of wall and stiffeners, preferably with
elements of length corresponding to half the wall
and stiffener thicknesses at the intersection,
very good judgements concerning the thicknesses
of these (short) elements have to be made.

Personally, I would use 2-D solid elements. In this
way, you do not introduce any errors at the
intersections. As a bouns, you would have the
opportunity of modeling the geometry of any weldings
present. If you need a full 3-d model, you would
want to use brick elements (Jan Christian's second
rule of modeling would be "there is no structure found
in nature that has zero volume or zero extension, so
always use solid elements").

What I did not ask was:
a) What is the purpose of the analysis?
b) Are there nonlinear effects to be expected?
c) Is the load constant (i.e. the load is pressure only)?
d) Is the analysis for sound engineering judgement, or
do you need to "sell" the analysis by means of
fancy color plots to a stupid and ignorant
management (I am a manager myself, so I know
what I am talking about)?
etc

Best regards
Jan Christian Anker

ANKER - ZEMER Engineering A/S
e-mail: jc.anker@a...
Phone: +47 22 13 95 80 FAX : +47 22 13 95 95
Address: Grindbakken 1, N-0764 OSLO, Norway
> Web Page: http://www.anker-zemer.com

> -----Original Message-----
> From: G. Janssen [SMTP:G.Janssen@s...]
> Sent: Friday, January 15, 1999 12:49 PM
> To: xansys list
> Subject: [xansys] Intersection of two plates

> From: "G. Janssen"

> I'm modelling a plane wall with stiffener plate perpendicular to the wall.
> I use shell 181 for both wall and stiffener.

> | | (wall) (T=18 mm Width between stiffeners 300 mm)

> |Q|===== (stiffener (20x100 or 150 mm))

> A pressure load at the left side of the wall will be applied.

> At point Q, the intersection of the two planes I choose to define two
> lines
> of nodes, one at the centreline of the wall, and on at the topside of the
> wallelements. The connection between these two are made by means of
> Contraint Equations.

> First the general FE question:
> Do I indeed need to model this intersection in this way or should I have
> taken the easy way of generating one line of nodes at the intersection
> lines of the mid-planes of the two plates?

> Second the ANSYS related question.
> To generate the CE's for nodes on the two lines I have mede two macro's.
> The first one to connect nodes at the keypoint locations of the lines and
> a
> second one for the inetrior nodes of the lines.
> In this proces I now arrive in the end with CE's with non unique DOF
> errors.
> Therefore: Is it possible to check if a node is already on a CE, either as
> MAster or Slave?
> (Or is there a better way in ANSYS to couple the nodes on two lines)

> Thanks

> Guus Janssen

Posts possibly associated with message #239AuthorDateScore
235Intersection of two platesGuus Janssen1999/01/15 
236Re: Intersection of two platesPavel Manas1999/01/15 
239Re: Intersection of two platesJan Christian Anker1999/01/15 
240Re: Intersection of two platesGuus Janssen1999/01/15 
245Re: Intersection of two platesChristopher Wright1970/01/01