Not linear (NL) releases

M-Phi diagram for NL releases

It is possible to perform an advanced not linear (NL) analysis in case the degrees of freedom are defined by using a M-Phi diagram (M - moment [kNm], Phi - angle of rotation [rad]). For the M-Phi diagram angular rotation Phi has a global meaning:


M-Phi diagram for NL releases


The option is available only if the rotational degree of freedom by My defined as spring.


Requirements for M-Phi diagram input

1. Diagram may not have discontinuity points (according to continuous function definition)

2. Diagram may not be defined in II and IV quadrants

3. Diagram must be increasing without vertical (dX=0) or horizontal (dZ=0) branches:

  • Vertical branch (dX=0) not allowed:
Rz-Uz diagram: dX=0 not allowed


  • Horizontal branch (dZ=0) not allowed:
Rz-Uz diagram: dZ=0 not allowed


  • The diagram must be only increasing: any part of the diagram can't be directed down as:
Rz-Uz diagram: only increasing


4. zero point [0;0] is absolutely necessary:

  • The diagram without zero point can not be defined:

Rz-Uz diagram with zero point     Rz-Uz diagram without zero point


Releases definition may be restricted by Technical Module No. 122 - in this case NL release diagram will be disabled