SLN to SPT connection with no tension

Hi

I’m modelling a tunnel in a trench, where I want the soil moving with the tunnel in compression, but not in tension. I’m trying to do this using SLNS REFT >SPT, but I can’t get the connection to work uniaxially. Is there any way of doing this?

I have made this example model to show the concept:

+prog aqua urs:35.1
    UNIT 6
    head Materials
    MAT 1 E 35000
    SREC 1 H 100 B 100 MNO 1
END
+prog sofimshc urs:35.2
    head Geometry
    SYST 2D GDIV 200000 GDIR NEGY
    CTRL MESH 1
    UNIT 6
    let#X 0,100,1100,1200
    loop#i X
        SPT 11+#i*10 X #X(#i) Y 0
        SPT 12+#i*10 X #X(#i) Y -1000
    endloop
    SLN 11 21 31 SNO 1
    SLN 21 11 12 SNO 1 ; SLNS REFT >SPT 21 FIX F
    SLN 22 41 42 SNO 1 ; SLNS REFT >SPT 31 FIX F
    SLN 12 12 42 SNO 1 ; SLNS fix PP
END
+prog sofiload urs:35.3
    head Load
    LC 1 TYPE 'NONE'
        BEAM SLN 11 TYPE PX PA 1
END
+prog ase urs:35.4
    head Analysis
    LC 1
END

In this case, I’d like the connection between SLN 21 and SPT 31 to be inactive.

I have tried creating an interface in PROG AQUA with CRAC 0, and added to the SLNS in SOFIMSHC but as interfaces has to be connected via edges, this doesn’t help me either.

aqua:

MAT  2 E 35000        
BMAT 2 MREF 1 CRAC 0.0

sofimshc:

SLN 21 11 12 SNO 1 ; SLNS REFT >SPT 21 MNO 2 TYPE INTF
SLN 22 41 42 SNO 1 ; SLNS REFT >SPT 21 MNO 2 TYPE INTF

Kind regards
Martin

Hello Martin

If I understand you correctly, you would like to connect a line to a structural point and the connection only transfers compressive forces. In this case I would work with non-linear spring elements and a non-linear analysis in ASE.

Please have a look at this older topic:

If I misunderstood your problem, please let me know.

Best regards
Frederik Höller
Your SOFiSTiK Support Team