Hi,

I would like to model a tendon that is pinned at the top to the OWT support structure, and connected to a pile anchor through a universal joint at the bottom.

What is did is the following (in sudyn)

- STRUCTURE JOINTS: Joint 20 is type 3 (Pin), with JointDirX 0, JointDirY 1.0 and JointDirZ 0.0, JointStiff 0.0
- STRUCTURE JOINTS: Joint 25 is type 2 (Universal), with JointDirX 1.0, JointDirY 1.0 and JointDirZ 0.0, JointStiff 0.0
- BASE REACTION JOINTS:

`RJointID`

25

`RctTDXss`

,`-Yss`

,`-Zss`

and`RctRDZss`

all 1,`RctRDXss' and`

-Yss` to 0 - MEMBERS:

`MemberID 24, MJointID1 20, MJointID2 25, MPropSetID1 1, MPropSetID2 1, MType 2`

- CABLE PROPERTIES:

`PropSetID 1 EA 1.489719e+10 MatDens 533.3242, T0 6280e+3 CtrlChannel 0`

When I try to run the case, at the beginning I got this error:

*Node 25 is an universal joint, number of members involved: 1*

- 8*
- 8*
- 8*

*FAST_InitializeAll:SD_Init:DirectElimination:BuildTMatrix:JointElimination: universal joints should only connect two elements.*

Based on Link:

*This version of SubDyn can, in fact, handle partially restrained joints by setting one or more DOF flags to 0 and providing the appropriate stiffness and mass matrix elements for that DOF via the SSIfile*

I therefore added a â€śSSI.txtâ€ť file in the BASE REACTION JOINT for RJointID 25, that looks like the following, but I still have the same error.

**Where is my mistake?**

`!---------------- Pile Head K and M elements -------------------!`

`!Equivalent Stiffness Constants: Kxx, Kyy, Kzz, Kxtx, Kxty..Kztx,Kzty,Kztz in any order; max 21 `

elements

`-1.98E+09 Kxty`

`-6.83E-02 Kyty`

`0.00E+00 Kzty`

`-2.73E-01 Ktxty`

`1.35E+10 Ktyty`

`0.00E+00 Kxtz`

`0.00E+00 Kytz`

`0.00E+00 Kztz`

`0.00E+00 Ktxtz`

`0.00E+00 Ktytz`

`7.00E+08 Ktztz`

`5.04E+08 Kxx`

`3.11E-02 Kxy`

`5.06E+08 Kyy`

`0.00E+00 Kxz`

`0.00E+00 Kyz`

`2.54E+09 Kzz`

`6.83E-02 Kxtx`

`1.99E+09 Kytx`

`0.00E+00 Kztx`

`1.35E+10 Ktxtx`