# Direction of transverse springs

I’m struggling with understanding the transverse direction of springs.

I have a 2D longitudinal model, made in a 3D system (in order to use axes).
When I define a spring with the main direction along the longitudinal axis, I want the transverse direction to be in the vertical direction.

However, when defining the spring, the transverse is in the perpendicular horizontal direction to the main direction, and I see no means of rotating the spring.

Please see the attached snippet below with the wished transverse direction shown with a red arrow.

``````+Prog SOFIMSHC urs:2 \$ Geometry
SYST 3D GDIV 100 GDIR NEGZ
ctrl mesh 1
SPT 1 X 0 Y 0 Z 0
SPT 2 X 1 Y 0 Z 0
spts no 3 ref 1 CQ 10 CP 100 CRAC 0.0 grp 1 type C DX 1 DY 0 DZ 0
end
``````

Hi MRCH,

as you can see in the manual, the transverse spring direction is a plane perpendicular to the axial direction:

The first parameter CA describes an axial stiffness along the principal direction of the spring. The second parameter CQ describes a stiffness component acting in the whole plane perpendicular to the axial direction.

In your case you need to define 2 single springs, both with a value CP:
spts … CP 100 DX 1 DY 0 DZ 0
spts … CP 10 DX 0 DY 0 DZ 1

Birgit

Hi Birgit

Thank you very much for your reply, I had a feeling that was the issue as well.

In your example, would there be any difference in writing:

``````spts … CP 100 CQ 10 DX 1 DY 0 DZ 0
``````

``````spts … CP 100 DX 1 DY 0 DZ 0
spts … CP 10 DX 0 DY 0 DZ 1
``````

The reason I’m asking is that in my main model which I’ve tried to summarize in the previous model, I see a vertical spring force in springs which have no transverse stiffness assigned. Please see the figure below:

The definition of the springs is seen below:

``````spt 361 ref pt 25501 z -8.25 mref ax 'ax'
sptp type 'f' ref 25501 grp 255
spts no 361 ref 358 CQ 0.0 CP 100000000.0 CRAC 0.0 grp 255
spt 362 ref pt 25501 z -4.43 mref ax 'ax'
sptp type 'f' ref 25501 grp 255
spts no 362 ref 359 CQ 25000000.0 CP 0.0 CRAC 1e+99 grp 255
spt 363 ref pt 25501 z -0.61 mref ax 'ax'
sptp type 'f' ref 25501 grp 255
spts no 363 ref 360 CQ 0.0 CP 100000000.0 CRAC 0.0 grp 255
``````

In my example there is no spring that contains a value for CQ, because that would be a spring in an undefined direction (plate - see manual).

It is important that you define a spring for each direction with a value for CP and an associated direction (DX, DY, DZ).

One can’t say more without a system.