XANSYS Message: 22592 [Go back to message list]
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Subject: Re: PRETS179 with Contact Element Problem
Author: Tom Davis
Date: 2001-04-10 12:32:00

I'm not sure what you mean when you say you are having trouble starting
this problem. You have to do a "restart". Here is an input file I have
been using to do a very similar problem. The first section loads the bolt.
The second section fixes the displacement. The third and fourth sections
add centrifugal and thermal loads. I think this is exactly analogous to
what you are doing. It has pretension and contact. This has worked well
for me.

Good luck.

TWD

resume,bolt.db
/config,nproc,2
/soln
antype,static,new
!f,60003,fx,4000,,70006,10003
cgloc
cgomga
tref
tunif
ddel,60003,all,70006,10003
f,60003,fx,4000,,70006,10003
solcon,on
eqslv,pcg
time,4000
nsubst,100,1000,1,off
auto,on
/title,Titanium, 4000 lb preload, No thermal, No rotation
/gst,on
solve

antype,,restart
fdele,60003,fx,70006,10003
d,60003,ux,%_fix%,,70006,10003
solcon,on
eqslv,pcg
time,5000
nsubst,1,1,1,off
auto,on
/title,Titanium, 4000 lb preload, %_fix%, No thermal, No rotation
/gst,on
solve

antype,,restart
cgloc,9.6657
cgomga,,79.6
solcon,on
eqslv,pcg
time,5760
nsubst,100,1000,1,off
neqit,100
auto,on
/title,Titanium, 4000 lb preload, No thermal, 760 rpm
/gst,on
solve
fini

/soln
antype,,restart
tref,77
tunif,194
solcon,on
eqslv,pcg
time,5877
nsubst,100,1000,1,off
auto,on
/title,Titanium, 4000 lb preload, delta T = 117 F, 760 rpm
/gst,on
solve
fini

Thomas W. Davis, P. E.
FSI International (http://www.fsi-intl.com/)
322 Lake Hazeltine Drive
Mail Station 4-1035
Chaska, Minnesota 55318
PHONE 952-361-7359, FAX 952-361-7393
tom.davis@f...

myron.l.jew@b...

oeing.com To: xansys

cc:

04/10/01 Subject: [xansys] PRETS179 with
Contact Element Problem
11:21 AM

Is there a scheme to use the the bolt pretension element (PTS179) in
a model with contact elements?

To simplify the problem for illustration purposes, I have a sector of
a bolt pattern and want to use contact elements (170/174) between the
cylinder and endplate.

| +---------+
CL | bolt |
| +-+-----+-+
|-------------| |----+
| end plate | | |
|-------------| |----+
| +----+ | |
| | c | | |
| | y | | |
| | l | | |
| | i | | |
| | n | | |
| | d | | |
| | e | | |
| | r | | |

I initially coupled the bolt and the cylinder interfaces to the
endplate respectively (CPINTF) and ran a case with the desired
preload on the pretension element.

I then started a new analysis, replacing only the couples between the
endplate-and-cylinder with 3D contact elements, applying the
pre-tension "displacement" to "K" node of the pre-tension element. I
am having problems on how to start this portion of the problem so
that the contact elements will converge and I can start adding
subsequent load cases.

What am I missing?

TIA

Myron
Boeing
SoCal

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Posts possibly associated with message #22592		Author	Date	Score
22590	PRETS179 with Contact Element Problem	Myron Jew	2001/04/10
22592	Re: PRETS179 with Contact Element Problem	Tom Davis	2001/04/10