Sequential

Sequential analysis is any type of structural analysis performed on a structure under prior loading (also termed preloading or prestressing).

The response of a structure is affected by its initial state, which is affected by the preloading/prestressing applied prior to the analysis of interest. Examples of sequential analysis include analysis of rotorcraft blades under centrifugal preloading, pillar-like structures under compressive preloading, preload arising from the pretensioning of bolts on a structure, and so on. Use SimSolid to account for such preloading or prestressing effects.

You can add or remove loads from sequential analyses to simulate additional loading or unloading, respectively.

Example

Structural 1 – Preload: Immovable 1; Nut tightening 1
Structural 2, Linked to Structural 1 – Loading: Immovable 1; Nut tightening 1; Force 1 – 20 N
Structural 3, Linked to Structural 2 – Unloading: Immovable; Nut tightening; *Force 1 deleted. Editing Force 1 to be 0 N has the same affect.

When the prestressing subcase is linear static, the prestressed stiffness matrix is given by:(1)

\bar{K} = K + K_{σ}

Where,

$\bar{K}$: Prestressed stiffness matrix
$K$: Original stiffness matrix
$K_{σ}$: Geometric stiffness matrix that defines the prestressing. This is based on the stresses of the preloading static subcase.

Depending on preloading conditions, the resulting effect could be a weakened or stiffened structure.

If the preloading is compressive, it typically has a weakening effect on the structure (for example, column or pillar under compressive preloading).
If the preloading is tensile, it typically has a stiffening effect (for example, rotorcraft blade under centrifugal preloading).

When the prestressing loadcase is a non-linear static subcase, the prestressed stiffness matrix $\bar{K}$ includes the geometric stiffness matrix $K_{σ}$ , and also accounts for the changes of $K$ due to the converged contact status carried over from the prestressing loadcase to the prestressed loadcase.