# Analysis wizard : Nonlinear static

Nonlinear static analysis uses dynamic relaxation to allow for nonlinear effects and large displacements.

## Definition

### Element slenderness

When checked, slenderness effects on individual beam elements are included by the use of stability functions. These obviate the need to include intermediate nodes in beam elements to consider their stability.

### Automatic load increment

When checked, the magnitude of each load increment (except the first increment) will be chosen automatically by the program. The *load applied in the first increment* is specified as a percentage of the total imposed loads. During the analysis, the loading is increased until the specified limits are exceeded. These limits can be expressed in terms of nodal displacement (translation or rotation) or load factor. They are defined in the GsRelax analysis task Ccontrol page of the **Analysis wizard**.

The magnitude of the automatic load increment is chosen by the program according to the likelihood of the convergence of the analysis in the previous load increment: the easier the previous load increment was to converge, the larger of the current load increment will be, and vice versa. If the analysis cannot converge for the current load increment, the load increment is reduced until the analysis does converge or the specified minimum load increment is reached. If the specified minimum load increment is reached, the analysis will stop; the current load level is probably the ultimate capacity of the model. The records of the incremental load factors and corresponding displacements are available after the analysis as ** Global results > Load factor / Displacement relationship** output.