Hello,

In general, it is known that the geometrical nonlinearity can be considered in two ways:

1- following geometrical nonlinear analysis, during which the equilibrium of the structure is studied based on the deformed shape. This means that the stiffness matrix starts to be updated according to the nodes' current position.  

2- Alternatively, there is another type of analysis, a linearized (approximated) form of geometric nonlinear analysis "Second order analysis", during which the equilibrium is also studied based on the deformed shape. The kinematic equation is linearized, but the stiffness matrix is updated by adding the geometric stiffness term, which depends on the acting internal forces.

Now, referring to Abaqus, in the static general analysis step, there is a choice to toggle on the "NLgeom" option in order to take the large deformations effects into account and that would be applying (geometric nonlinear analysis). 

Accordingly, I would like to ask, if applying general static analysis without activating "Nlgeom" option is about applying "second order analysis"??

Thanks for your cooperation.