High stiff chevron frame

[Gholamreza]

Hello, I wonder to know How to model a chevron frame with high stiffness ? I used code below but I keep receiving this error:

node 1 0. 0.
node 2 3. 0.
node 3 1. 2.
node 4 2. 2.

fix 1 1 1 1
fix 2 1 1 1
.
.
.
uniaxialMaterial Elastic 3 1e10
.
.
.
element truss 4 1 3 0.5 100
element truss 5 3 4 0.5 100
element truss 6 2 4 0.5 100
.
.
.
Error: ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (2, 0)

[fmk]

with truss elements you have a mechanism .. have you any structural analysis background?