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Linear static analysis

For most users the most common use of GSA is for linear static analysis. The Getting started manual guides a new user through the stages of building and carrying out a linear static analysis. In all cases a knowledge of linear static analysis is a pre-requisite for the more advanced analysis options.

Analysis​

A linear static analysis can be carried out using the Analysis > Analyse all menu command. (See Running analyses.)

Results​

The results of a linear static analysis break down into three categories:

  • Global results – total loads and reactions
  • Nodal results – e.g. displacements at all nodes and reactions at restrained nodes
  • Element results – e.g. forces and moments in elements

Details of results available and how they can be viewed are in the Results display options section.

Linear 2D element analysis​

The same set of results is available from a 2D element analysis with a number of additional results for forces and moments, and stresses in 2D elements.

Results for 2D analysis are often most easily understood graphically. This can be done by selecting the Graphics > Display > Settings > Contour settings or Graphics > Display > Settings > Diagram settings commands or the Contour settings or Diagram settings buttons on the Graphic display toolbar. Details of results available and how they can be viewed are in the Results display options section.

Unlike analysis with beam elements there is no requirement for continuity of stress and force results across 2D elements so contour discontinuities are to be expected. The user may choose in the contour settings to average the results at the nodes giving smooth contours, but this should not be done until the user is satisfied that the discontinuities are minor, so as not to mask poor results. Large discontinuities indicate that the mesh is too coarse. 2D elements results are discussed in more details in Interpreting data and results – 2D element results.

If all results for 2D elements are stored the model can become very large, so the user may select which force and stress results to store. This can be done from the Tools > Preferences menu command; select Results and select the 2D element results that are required. This has no effect on existing results and only affects subsequent analyses.