Cushion roof

I’m trying to model an ETFE cushion with steel edges for a home work at my university
I created two lyers of ETFE and wanted to support them with the steel edges and prestress it using a volume between the two layers, but when I’m trying to support the upper leyer with the steel edges it woldn’t work

I want to support the edges of the upper ETFE with the edges of bottom one

this my code

$Folienkissen; Lagen ETFE

#define laenge = 1 $m; x-Richtung der Folie → ED
#define breite = 1 $m; y-Richtung der Folie → TD

#define abstand = 0.001 $m; abstand zwischen die beide membran ebenen

#define dicke_o = 0.25 $mm;
#define dicke_u = 0.25 $mm;

#define E = 1000 $MPa;
#define nue = 0.45 $-

#define druck = 0.3 $kN/m 300 pa
#define druck_s = 0.6 $kN/m 600 pa

#define vorsp_o_ED = 1.56 $kN/m
#define vorsp_o_TD = 0.78 $kN/m
#define vorsp_u_ED = 1.56 $kN/m
#define vorsp_u_TD = 0.78 $kN/m

#define schnee = 0.52 $kN/m
#define windsog = -0.78 $kN/m
#define winddruck = 0.5 $kN/m

#define m = 10 $unterteilung in x_Richtung
#define n = 10 $unterteilung in y_Richtung

+prog aqua urs:1
kopf Kissenstruktur - ETFE
echo VOLL VOLL
norm ‘DIN’ ‘EN1993-2005’
mate nr 1 E $(E) mue $(nue) E90 $(E) GAM 0 BEZ ‘ETFE-FOLIE’
nmat nr 1 art MEMB

Norm DC EN 1993-2005 cat A

stah 2 s 355
stah 3 s 355
qnr 3 mnr 2 bez ‘Randträger’ ; prof 1 warm 193.7 16 $Rundstahl nach EN 10060
qnr 4 mnr 3 bez ‘Stützen’ ; prof 2 warm 193.7 10 $Rundstahl nach EN 10060

ende

+prog sofimsha urs:2
kopf Kissenstruktur - ETFE - Volu Luft Volume Technik

syst init $ system löchen aber die Systeminfo behalten
syst 3D GDIV 10000

knot 1 2.3 -5.3 0
knot 2 2.9 -6.5 0
knot 3 4.3 -6.6 0
knot 4 5.2 -5.5 0
knot 5 3.2 -4.2 0
knot 6 4.7 -4.5 0

knot 11 2.3 -5.3 0.001
knot 12 2.9 -6.5 0.001
knot 13 4.3 -6.6 0.001
knot 14 5.2 -5.5 0.001
knot 15 3.2 -4.2 0.001
knot 16 4.7 -4.5 0.001

knot 1 fix pp
knot 4 fix pp
knot 5 fix pp

$knot imsh 11 12 fix pp
kine 11 pp 1
kine 12 pp 2
kine 13 pp 3
kine 14 pp 4
kine 15 pp 5
kine 16 pp 6

grup 3
stab fit ka 1 ke 2 qnr 3 teil $(n)
stab fit ka 2 ke 3 qnr 3 teil $(n)
stab fit ka 3 ke 4 qnr 3 teil $(n)
stab fit ka 4 ke 6 qnr 3 teil $(n)
stab fit ka 6 ke 5 qnr 3 teil $(n)
stab fit ka 5 ke 1 qnr 3 teil $(n)

grup 1
$quad fit k1 1 k2 3 k3 4 k4 5 m12 2 m34 6 mnr 1 t 1[mm] kr posx m $(m) n $(n) $ area number 1o
quad fit k1 1 k2 2 k3 3 k4 5 mnr 1 t 1[mm] kr posx m $(m) n $(n)
quad fit k1 3 k2 4 k3 6 k4 5 mnr 1 t 1[mm] kr posx m $(m) n $(n)

grup 2
$quad fit k1 11 k2 13 k3 14 k4 15 m12 12 m34 16 mnr 1 t 1[mm] kr posx m $(m) n $(n) $ area number 1u
quad fit k1 15 k2 13 k3 12 k4 11 mnr 1 t 1[mm] kr posx m $(m) n $(n)
quad fit k1 15 k2 16 k3 14 k4 13 mnr 1 t 1[mm] kr posx m $(m) n $(n)

ende

-prog ase urs:3
kopf Formfindung - Volu Luft Volume technik
echo voll voll
syst prob th3 nmat nein iter 400 tol 0.001
grup -
grup 1 faks 1e-10 vorx $(vorsp_o_ED) vory $(vorsp_o_TD) $ bringe Voespannung ein für obere Foile
grup 2 faks 1e-10 vorx $(vorsp_u_ED) vory $(vorsp_u_TD) $ bringe Voespannung ein für untere Foile
volu 1 grp 1,2 V0 $(laenge)$(breite)$(abstand) P0 $(druck) $posi negz
lf 1 fakg 0 bez ‘Formfindung’

ende

Hello

I think you have to couple all of the nodes. As you can see in the displayed image of your system, only a few of the nodes are connected. So try to define support conditions (or try to couple them). If you want to use steel beams as support (I’m not entirely sure if that works), the QUAD elements of the two areas should have at least the same nodes as the beam elements. At the moment only the nodes in the edges are connected.

For reference, you should look at the following TEDDY example.

TEDDY > File > Examples > ase > membranes >

Best regards
Frederik Höller
Your SOFiSTiK Support Team

Thank you very much, JFH, for your kind reply.

unfortunately, I tried the following examples one by one before writing this post, and still can’t make a rigid support for a line (which I need) as following:
kine fit 11 12 pp 1 2 (it raises an error*** syntax wrong), to rigid each node in the line with its offset point
if such command is somehow available, it would solve my problem

Best regards