## B. Static Analysis of an Elastic Structure Subjected to a Force (STA1)

In this analysis, only the displacement field has to becomputed and w is equal to zero. Thus, the matrixe quation (1) is reduced to:

[Kuu] U = F

The user provides the loading data F. The code computes U. F must be precisely defined for thefinite-element model. This means that it must be divided by 2 p if the model is axisymmetrical and by 2 if a symmetrical plane limits the mesh. The user must define a mesh and boundary conditions eliminating the rigid body modes that induce singularities of the system ofequations. Only one loading case can be solved at a time. Taking internal losses into account does not make physical sense in this analysis and thus isnot possible.

The applied forces can be concentrated at the nodes (see LOADS entry) or distributed by using interface elements andby prescribing the pressure with the EXCITATIONS command. The matrix [Kuu] is assembled and stored in afile by columns. Gaussian algorithms are used to solve the problem, in singleor double precision. It is also possible to apply a force (STA1)and to prescribe displacements (STA3) at the same time.