NASTRAN was principally used to perform failure analysis and redesign process equipment. It was also employed in the evaluation of vendor designs and proposed design modifications to existing process equipment. Stress analysis of forced draft fans, distillation trays, metal stacks, jacketed pipes, heat exchangers, large centrifugal fans, and agitator support structures are described

Winter, J. R.

English

NASA Technical Reports Server

TYPICAL USES OF NASTRAN IN A PETROCHEMICAL INDUSTRY 
J. Ronald Winter  
Tennessee Eastman Company 
The two major objectives of this r e p o r t  are (1) t o  p r e s e n t  a  summary of 
t h e  t y p i c a l  u s e s  of NASTRAN i n  a  pe t rochamica l  i n d u s t r y  and ( 2 )  t o  d e s c r i b e  
the unique e n v i r o n ~ r e n t  i n  which the program is used a t  t h e  Tennessee Eastman 
Company (TGC) . 
BACKGROUND 
N A S T R .  i s  p r i n c i p a l l y  used a t  TEC t o  perform f a i l u r e  a n a l y s i s  and 
r e d e s i g n  p r o c e s s  equipment. I n  a d d i t i o n ,  i t  i s  employed i n  t h e  e v a l u a t i o n  of 
vendor  designs and proposed d e s i g n  m o d i f i c a t i o n s  t o  e x i s t i n g  p r o c e s s  equipment.  
I t s  d i r e c t  usag; as a d e s i g n  t o o l  i s  q u i t e  l i m i t e d  a t  t h i s  rime, b u t  I f e e l  
conf ident  t h a t  th!- a r e a  of usage w i l l  grow i n  t h e  future. 
NASTRAN usage as a f a i l u r e  a n a l y s i s  t o o l  i s  n o t  un ique ,  b u t  its usage f o r  
t h i s  purpose i n  a p r o d u c t i o n  environinent w i t h  pr imary emphasis on minimizing 
l o s t  p roduc t ion  due  t o  m e c h a n i c a l / s t r u c t u r a I  f a i l u r e s  i s  probab ly  unique.  Its 
use  i n  t h i s  way nreans t h a t  s o l u t i o n s  t o  sometimes q u i t e  difficult problems must 
be obta ined  i n  r e l a t i v = l y  s h o r t  p e r i o d s  of time. This o f t e n  e n t a i l s  t h e  use of 
nrodels wi th  much c o a r s e r  mesh networks t h a n  would normal ly  be desired i f  more 
time was avai1abl.e.  However, w e  have found t h a t  even w i t h  t h e  u s e  of rela- 
tivc1.y coarse models one can o b t a i n  s a t i s f a c t o r y  r e s u l t s  i n  a minimal l e n g t h  o f  
time. I n  any e v e n t ,  the r e s u l t s  ob ta ined  arc g e n e r a l l y  s u p e r i o r  t o  those 
o b t a i n e d  by h a s t y ,  e r r o r  p rone  hand c a l c u l a t i o n s  t h a t  u s u a l l y  requi re  numerous 
s i m p l i f y i n g  a s s u ~ n p t i o n s  i f  a s o l u t i o n  i s  t o  be o b t a i n e d  i n  the desired t i m e  
f rame . 
We also use NASTRAN on some relatively s m a l l  problems s imply because the 
r i g i d  formats  a v a i l a b l e  i n  NASTRAN a l l o w  o n e  t o  perform several d i f f e r e n t  types 
o f  a n a l y s e s  u s i n g  essentially the  same xodel. For i n s t a n c e ,  t h e r e  are numerous 
cases where a s t r e s s  a n a l y s i s  (Rigid Focna t s  1 o r  2),  a h e a t  t r a n s f e r  a n a l y s i s  
(Rig id  Ponnats  1, 3 o r  9) and a dynamic a n a l y s i s  (Rigid Formats 3 ,  8 ,  9 ,  or  11) 
a rc  requ i red  t o  i n s u r e  t h e  complete s t r u c t u r a l  adequacy of a redes igned  compo- 
n e n t .  I n  t h e s e  c a s e s  we f i n d  t h i s  p rocedure  more e f f i c i e n t  and more economical  
t h a n  performing Ehe a s s o c i a t e d  s o l u t i o n s  via classical mechanics  methods. 
https://ntrs.nasa.gov/search.jsp?R=19780024527 2020-03-22T01:55:28+00:00Z
It1 t l 1 . L ~  papcr tllcrr? will h e  no r r t t c a ~ p t  t o  g i v e  "de tn i l ec l "  clesc~:iptions of 
nny pnr t .Lcu l i~ s  1taodc2 or  tilc t :csults.  I n  gcnernl., tl~er;: ? r i l l  ba EI b r i e f  
dcscript.Lon o f  sevct-nl l~roblclr ls  ntlcl t l l c !  ~ s s o c i n t c d  ruoclels, the  t y p c  n t ~ a l y s e s  
pcrforacd on t h c  noclcl s ,  o suaaun.ty of t l ~ c  t e s u 1 . t ~  and c o ~ ~ c l . u s i a t ~ s ,  and t y p i c a l .  
~ ~ n r l c f o r ~ ~ r c c l  ~ I I L I  r l e f o r ~ ~ ~ e r l  p l o t s .  I 'hotos of' salrle F n i l u r e s  w i l l  a l s o  b e  included. 
Somc tyt>. tcal  I I ~ O C L ' S S  C C I C I ~ ~ ~ ~ I I ~ I I L :  C I IT IC  110s hecn  n ~ ~ a l y z c c l  v f u  Nr\S'l'IUN are listetl 
below. 
R i g i d  
Type Aun1.y sos Fonrrn ts 
D i s  t i  Lla t i o n  Trn ys S trlr i c  , No tma l  Ilode 
(0rthugonn;l.l.y S t  i f  rancil 
I'ln tes)  
S tcc.L Stnclis (Cll i~nneys)  Stat:i.c, Normal Node , 1,3,5,8 
Fccqurncy Rcsponsc, R u c k l i n g  
Lnrgc J ~ c k c t c r l  13:ipc 
Sys t:e~as 
S t o  t i c  1 
I-lcat Eschnngcrs  S t a t i c ,  Hcnt  Transfer 
(Shel l  6 Tubc r d l . t h  S i n g l e  
and Double Tube S h e e t s )  
Lnrgc C e n k r i E u j i a P  Fans StaLic, N O ~ I I I L ? ~ .  Elode 
Il'nble 2:  Annl,yses Not lliscussad it1 'l'1li.s Pnpc r  
I3iuretn:Llic Jnnc t j . ons  S t n r i c  
Rig i c l  
l'ormn ts 
( 5 )  Ana:Lysis o f  P i p e  Systems 
( 6 )  P r n ~ a c s  and Trusses  
( 7 )  Statage S i l o s  
(8) 1,srge Dryeru/~lenclet :s  
( 9 )  Prcssurc Vessels 
(10) She1l.s A s s o c i a t ~ d  1 J i t l i  
Colnbustiotl Chambers 
(11)  I'las t i c  Vcssc:Ls 
(12) Cyclones 
(13)  Es t ruders  
S t n  t i c ,  Nornrnl Node, Forced 1,3,0,9 
13csponsc, Frequency l lcsgansc 
S t a t i c ,  Uuckl ing  1,5 
S t ~ i t i c ,  Ouckl ing  1,s 
S t a t i c  1 
S t a t i c  1 
S t a t i c  1 
Static 
S t r ~ t i c ,  Normal Elodc 
S t a t i c  
13 i scuss~on  of A n a l y s i s  T , i s ~ c d  in ll'abl& 
(I) Forced Draft  Fan Fa i l .u rc  
Dur ing  n t teulp ts t o  ba.l.nnce a Jurgc f o r c e d  d r a f t  Can, t h e  unll: d i s i n t e g r a t e d  
st a rtl t lationnl speed of  - 900 rpnl (15  1.1~). The n o r a a l  o p e r a t i n g  speed f o r  
t h i s  un i t  i s  1200 rplu (20 I lz ) .  See F i g u r e s  1, 2, and 3 Ear photos  of a t y p i c a l  
forccrl d r a f t  Fan and t h e  d e b r i s  Froa~ c l ~ i s  f a i l u r e .  
I n i t i a J . l y  it was i inposs ib lc  t o  deterur tne  Ero~n the resulting d e b r i s  what  
caused the Failure. Several t h e o r i e s  were pos tu ln tec l ,  b u t  t h e r e  was insuffi- 
cient prool: t o  s u l s t ~ u r i a t e  nuy p a r t i c u l a r  t h e o r y .  T h i s  led to a NASTflnN 
analysis in all e f f o r t :  t o  prove o r  d i sprove  several  p o s t u l a t e d  sequences  01 
e v e n t s  that could have resulted : L n  t h e  some fail.i~i:e. Tlle NASTRAN tirodel is 
S ~ O I J I I  ~ I I  Pigtire 4 .  R i g i d  formats 1 ( s t a t i c  nna1.ys. i~) nncl 2 (static ana lys i s  
w i  tll :incl: C .La1 r e l i e f )  were elnployecl . Tlre results ind:icn ted t h a t  the h i g h e s t  
sL~:css l c v e l s  were a t  thc  e ~ ~ d s  o f  each blade and n o t  i n  t h e  o u t e r  rings. nut 
t h e  l eve l s  were not  s u f f i c i e n t l y  high t o  cailse E a i l u r c  i n  clie absence o.F a 
defect (crack, poor w e l d ,  e t c . ) .  This lecl t o  a care.fr!l r ee sn tn lnn t ion  of rhe 
b l a d e s  (see F i p ~ t - e  7). Thls i n spec t ion  revealect t h a t  b l a d e s  lilade by two 
cii t 'Er~:cnt  ~nauufac  t u r c r s  were emplojted. * The in spec ti or^ a l s o  revealed t h a t  only 
t h e  b l a d e s  o f  a welded cons t ruc t ion  l~acl broken while t h e  formed b lades  I-tad no r .  
*Altl~ough tlrc use o f  two d i f f e r e n t  b l a d e  designs on t h e  s a m  f a n  is n o t  
desirabl.e, this was found t o  be a conmlon practice.  
Detailerl  inspection of  t h e  ends O F  the  brolccn blnclcs re-,teal.ecl c s t r en lc ly  poor 
wclc1:lng ( s e e  Figi11:e 3 ) .  'l'hu alujor wcld clcfcct  wns c l n s s i f i c d  as  lack of 
~ ~ e u e t r n t i o n ,  Of c o u r s e ,  ochci: veld r l c l ? c c ~ s  ucli L?S ~ . ) o r o s I t y ,  u ~ ~ c l e r c ~ ~ t t i ~ ~ g ,  
ecc.,  \\rere n l s o  prescri t  huc wcro no t  of sucli L? S C V C ~ C  t i a t ~ ~ l : ~ ) .  \dllcn t h e  
r c s ~ ~ l t l n g  NASTlUN sti:css l c v c l s  nc t h e  c ~ r d s  o f  t h e  blaclcs were n~ul.tipl.iecl by 
t h e  n p p l i c o b l c  s t r e s s  c o t ~ c e t i t r n t l a u  F a c t o r ,  tlie s t r e s s  levels iicrc raoro tlrnn 
suFE1c:Lent t o  cause F n i l u r c .  S u b s c q u e ~ ~ r ' l y ,  scve~ :n l  r u n s  were madc t o  i n v c s t i -  
g a t e  {:lie l o a d s  assu~ l r i l~g  one o r  marc hla t les  lincl broken.  'I'hese r e s u l t s  i n d i c a t e d  
t h a t  t h c  f o i l u r c  pil t tcvn woulil be stai lar:  t o  tllu t ivlclicntecl by t h c  d c b r i s .  
( 2 )  I1ist:Ll.l.n t i o n  Trays (O~+tliojiot~n:LJ.y S t  iFFer~ed 1':l.o ~ c s )  - 
t\ d i s t . i l . l a t l o n  t r a y  csse l ; t in l l .y  c u u s l s t s  of  n t h i n  p l a t e  suppor ted  by 
bearas. A typical. cl:is t illa ti011 cray is sho\m i n  F i g u r e  5. Numerous C-ailu~:as 
have been encoun te red  w l t h  such  trays.  The E n i l u r c s  hnvc been a t  t r ibu tec l  t o  : 
(L) P a t i g u c  a s s o c i a t e d  w i t 1 1  norlrinl 111-ocess pulsacr ior~s  ( F i g u r e  G ) .  
( 2 )  llecsonnnk o r  near r e s o n a n t  c o n d i t i o n s .  
( 3 )  Large p r c s a u r c  p u l s c s  clue ta p r o c e s s  u p s e t s ,  s t a r t - u p s ,  c t c .  
lpJ a s h i ~ i g  is a comnron p rob le~n  ( F i g u r e s  7 and 8) . 
( 4 )  Carros ior l  ( g c ~ ~ c r a l  t tnc lc  ancl s p c c i r i c  t y p c s  o r  a t t u c k ,  c . g . ,  stress 
c o r r o s i o t 1 ~  . 
iVt\STPdN anal.yses hove e s s e n t l i n l l g  e;Lirtll.~~a t e d  t h e  First two f a i l u r e  
r t~ccha~~is tns  ar-rd hus oicled u s  i n  d e s i g n i l ~ g / s p e c l f y i n g  t r a y e  t h a t  a r c  tnore 
r e s i s t c r ~ ~ t :  o  minor p tessurc  p u l s e s .  NAS'I'IZAN is a l s o  used t o  eval . t late v e i ~ d o r  
t r a y  clesigtls espoc ia l . ly  iE an unusua l  clesign is s ~ ~ b i n : l t t e d  o r  iF the p a r t i c u l a r  
cl t~sign is L I S C ~  :L11 a critical app l . : i ca t io~ t .  
'ryplcal t r a y  models n1:c s h o ~ a ~  i n F i g u r e s  9 and 10, '1:ypictll p l o t s  of  t h e  
First: ancl second modes a r e  shown i n  P ig t l r e s  1.1 and 1 2 .  
( 3 )  Eletnl Staclc A i ~ a l y s i s  
Due t o  p o t e n t i a l  po1l.ution problcnrs, i t  was des:tred t o  add a 1 5 . 2 4  meter 
(50 Ft . )  e x t e n s i o n  t o  an existing 30.48 ~ileter (100 Ft.) staclc.  The e x i s t i n g  
o i l  Eired b o i l e r  staclc i s  s h o ~ n i  i11 F i g u r e s  1 3  ancl 14. Dt~e t o  potential v o r t e x  
s l~ec ld i t~g  prabl.cms, an  a n a l y s i s  was ~:equescccl. T l ~ c  ~ r e s u l t i i ~ g  NAS'l'l'dN tuoclel i s  
shown i n  F i g u r e  15. A NASTWN modal analysis showecl L'l~ot a 1:esonarIt c o n d i t i o n  
lsould occur  d u e  t a  vo r res  shedcli.ng at: ~noclerate t o  h i g h  r~ i l ld  v e 1 . o c i t i . e ~  w l ~ i c h  
were t y p i c a l  i n  t h c  p a r t i c u l a r  r e g i o n .  See 1Tigurc 3.6 f o r  t h e  First bending 
nrocle, A s ~ r z t i c  a n n l y s i s  a l s o  rcveal .ed t h a t  t h e  fo t~nclnt ion l o a d s  were f a r  too 
l a r g e .  Aclclitinnal a ~ l a l y  s e s  ~:cvealccl t h a t  t h e  slraclc would e t lcounter  a11 o v a l i n g  
ccsouant: c o n d i t i o r ~  a t  h i g h  w i n d  v e l o c i t i e s .  T h u s ,  i t  Isas sharm t h a t  t h e  
d e s i r e d  c o r r e c t i v e  a c c i o n  w o u l d  r e q u i r e  t h e  i n s t a l l a t i o n  of new s t a c k s .  
( 4 )  J a c k e t e d  P i p e  A n a l y s i s  
I n  many s i t u a t i o n s  i n  a p e t r o c h e m i c a l  p l a n t  i t  i s  n e c e s s a r y  t o  inn in ta in  
the te r i~pera t i t rc  of a p roduc t  i n  a  p i p e l i n e  t o  p r e v e n t  s o l i d i f i c a t i o n .  The use  
of jaclceted p i p e  (stcstn i n  t h e  e x t e r n a l  p i p e ,  p r o c e s s  material i n  t h e  i n n e r  
p i p e )  is o f t e n  used LO a c h i e v e  t h i s  r e s u l t .  I n  these cases the i n t e r n a l  p i p e  
is t y p i c a l l y  a  300 s e r i e s  s t a i n l e s s  steel w h i l e  tlie o u t e r  p i p e  (steam j a c k e t )  
is carbon s t e e l .  Due to t h e  t e m p e r a t u r e  d i f f e r e n c e  between t h e  i n n e r  and o u t e r  
p i p e s  atid rhc  f a c t  cha t  t h e i r  t t ~ e r n l a l  c o e f f i c i e n t s  of expans ions  a r e  q u i t e  
d i t f c r r s n t  one can encoun te r  l a r g e  d i f f e r e n t i a l  thermal  expansionrl. As a r e s u l t  
of  t h e s e  c o n d i t i o n s ,  w e  have encountered numerous f a i l u r e s  w i t h  t h i s  t y p e  of 
p f p e l l n e  i n  the p a s t .  NASTRAN, with t h e  MT~/ - r ig id  c lement  c a p a b i l i t y ,  is  
i d e a l l y  s u i t e d  f o r  "rapid"  a n s l y s i s  of t h e s e  type  p i p e l i n e s .  A typical p i p e l i n e  
model i s  s h a ~ l  i n  F i g u r e  1 7 .  The r e s u l t s  of a NASTRAN a n a l y s i s  of a v e n d o r ' s  
d e s i g n  b e f o r e  and a f t e r  t h e  i tnplementa t ion of m o d i f i c a r i o n s  based on NASTRAN 
a n a l y s e s  i s  shown i n  F i g u r e s  1 8  and 1 9 .  The NASTRAN a n a l y s e s  of severa l  l i n e s  
l e d  t o  t h e  development of a set of  g e n e r a l  j a c k e t e d  p i r z  d e s i g n  g u i d e l i n e s  t o  
b e  used by e n g i n e e r s  and d r a f t s m e n .  These l a y o u t  g u i d e l i n e s  have virtually 
e l i m i n a t e d  f a i l u r e s  i n  t h i s  t y p e  p i p e l i n e .  
(5) Heat Exchangers 
The f a i l u r e  of  the  t u b e  s h e e t / E l a n g e  assembly of s e v e r a l  vendor des igned  
h e a t  exchangers  l e d  t o  a NASTW! a n a l y s i s .  The t y p i c a l  f a i l u r e s  encountered I n  
t h i s  c a s e  a r e  shown i n  F i g u r e s  20 and 21. The a s s o c i a t e d  f i n i t e  element models 
are shorn i n  F i g u r e s  22 and 23. The NASTRAN a n a l y s i s  r e a d i l y  showed that- 
d i f f e r e n t i a l  r a d i a l  thermal  expans ion  was t h e  major c a u s e  of f a i l u r e  (see 
F i g u r e  2 4 ) .  However, d i f f e r e n t i a l  the rmal  expansion between t h e  t u b e s  and s h e l l  
w a l l  a l s o  c o n t r i b u t e d  t o  t h e  problen~. The u n i t s  were  r e d e s i g n e d  based on the 
N A S T i N  r e s u l t s .  
( 6  Large  C e n t r i f u g a l  Fan 
The development of c r a c k s  i n  t h e  l a r g e  c e n t r i f u g a l  f a n  s h o ~ m  i n  Figure 25 
l e d  t o  t h e  development of a NASTRAN model of a p o r t i o n  oE t h e  fan.  Tlie b a s i c  
model is shown i n  F i g u r e  26 .  A s  expected, t h e  s t a t i c  a n a l y s i s  shoved t h a t  t h e  
h i g h e s t  stress l e v e l s  were i n  t h e  r e g i o n  where t h e  cracks had appeared.  
However, t h e  s t r e s s  l e v e l s  were not s u f f i c i e n t l y  h i g h  t o  cause f a t i g u e  c r a c k s  
t o  develop i n  the a p p l i c a b l e  time frame. This l e d  t o  a lllodal ( r e a l  e i g e n v a l u e )  
a n a l y s i s .  These r e s u l t s  r e v e a l e d  t he  t r u e  c u l p r i t .  A p a n e l  n a t u r a l  f r equency  
exisred r e l a t i v e l y  c l o s e  t o  a  normal o p e r a t i n g  f requency .  The a p p l i c a b l e  mode 
s h a p e  is shown i n  F i g u r e  2 7 .  Since  t h e  p a n e l  f r equency  w a s  j u s t  below t h e  
normal o p e r a t i n g  f requency ,  i t  was established t h a t  t h e  fan was be ing  s e r i o u s l y  
,amaged dur ing  each  s t a r t - u p  and shutdown. Unt i l  a new fan  could  b e  b u i l t ,  i t  
w a s  recommended t h a t  t h e  fan b e  a l lowed t o  r u n  c o n t i n u o u s l y  i f  p o s s i b l e .  It 
w a s  l a t e r  e s t a b l i s h e d  t h a t  due to p r o c e s s  problems and b e a r i n g  problems the 
u n i t  had been s t a r t e d  and s t o p p e d  numerous times d u r i n g  the  p e r i o d  b e f o r e  the 
c r a c k s  were d i s c o v e r e d .  
The NASTRAN a~~alysis established the cause of the f a i l u r e  and served a s  
ehc bas is  f o r  d e s i g n i n g  a new Pan. The ntodel was also used to modify the 
original f a n  which now serves as  a back-up. 
Agitator Suppor t  Structures 
Inadccluate struct~~ral supports f o r  large agitators have been d i a g n o s e d  v i a  
N A S T W  analysis to be tile cause of severe shaft: wear, p r e m a t u r e  bearing 
failures and craclciog of the a g i t a t o r  h o u s i n g s .  This prob lem was r e s u l t i n g  i n  
unusually h i g h  ntaintenance c o s t s .  As a r e s u l t  of t h e s e  analyses, a  new design 
~)rocedure wl~ich accounts for clynainic effects has been developed. A t y p i c a l  
nlorlel of an a g i t a t o r  support system is sl~own in F i g u r e  28. 
CLOS I N C  COPDIZNTS 
From t h e  previously d i s c u s s e d  t y p i c a l  uses  of NASTMN, it: should be 
evident t h a t  o u r  use O F  rile program is quite broad.  I 42  have found NASTRAN t o  
b e  t h e  only d i v e r s i f i e d  t o o l  presently ava i l ab le  which allows t h e  user to deal 
wirlz a very wide var ie ty  of d i f f i c u l t  problems i n  a r e l a t i v e l y  s h o r t  pe r iod  OF 
time. Needless to s a y ,  we are very dependent on the  c a p a b i l i t i e s  a v a i l a b l e  i n  
this program. 








FIGURE 9: TYPICAL MODEL OF A LARGE DIAbIETER DISTILLAPION TRAY 
FIGURE 10: TYPICAL MODEL OF A SMALLER DISTILLATION TRAY 



T 
1 5 . 2 4  m (50 Et.) EXTENSION 
': L 
30.48  In (100 Et.) 
Y' 7.62 m (25 ft.) 
F I G U R E  15: BASIC MASTlUN STACK PIODEL 
:)ltIGlNAL PAGE 1s 
Ok' POOTI CJUhLI'iY 
, l ay  Plot 
3.25 Hz 
FLGUPd 1G: FIRST STACK BENDING f.IODE 
G r i d  PoillC Nu~irbers f o r  I n n e r  Process Pipe 
FIGURE 1 7 :  TYP1Ck.t PIODEL OF JACKETED PIPE SYSTEM 
F I G U F 3  18: RESULTS FROI4 ANhLYSIS OF DESIGN SUBMITTED BY VENDOR 
Gb= #+ffOps) I- c,+= 2 9 p i  6~ = BS; ; 
Hey : 
6? = r o m d i ~ r  d s hiss J t s f c 2 4  s k fe e y ~ w  f&. 
, 
Gi = ~ a x i ~ u m  bp.vdjwy sfrcss a f 5& 8 dy 5sk fe cyrraJ,, 
5 = #xrk/ sfm6s 2 #  sicady sfifr a p e m - I ~ i ~ .  
Go =.#~x;ML/M Corn dried shes fat- a ve f // 
fhsrmo/ ewpaus/bn (d r=01 
6, = ~ z x i n u m  coold;nrd ~ b e s s  f r r  dtgfer~uk/ 
+&rma l cupa NS / i ~  (4 T= go F). 
9; .-- y/,+ /d 5fecap #4 = 3 7 3 0  #& Q 500 'F 
NOTE: This  analysis was 
performed prior to conver- 
s ion  to metric units, 
therefore all units are 
P" in t h e  English System. ~ ~ f , ~ V e  )!,+I i f  = /A) 3 4 a p i  @ 5 d d - b  
NASTRAN MODEL & - L A  
9 
= / qb5#ps i  
b'f ALL 
NOTE: Thi s  analysis was 
performed prior to conver- 
sion t o  metric u n i t s ,  
t he re fo re  a l l  un i t s  are 
i n  the English System. 4. 6, = 136 77pr.; 9 r 
4 5 
FIGURE 19: RESULTS NTER MAKING R E V I S I O N S  BASED ON NASTRAN ANALYSIS 


FIGURE 22: TYPICAL MODEL OF A SINGLE TUBE SHEET ASSEMBLY 
FIGURE 2 3 :  TYPICAL MODEL OF A DOUBLE TUBE SHEET ASSDBLY 
FTGUIE 24:  ?XERM-&LY INDUCED DPFORMATIONS OF A DOUBLE TUi3E SHEET ASSDIBLY 



FIGURE 28: MODEL OF A TYPICAL AGITATOR SUPPOET SYSTCq 


Typical uses of NASTRAN in a petrochemical industry

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