Contents     Functions              PDF Index

fe_caseg

• Assemble
• StressCut
• StressObserve
• ZoomClip

Purpose

Gateway functions for advanced FEM utilities in SDT, regarding assembly, integrated case definition and post-treatments.

Description

This function is only used for internal SDT operation and actual implementation will vary over time. The following commands are documented to allow user calls and SDT source code understanding.

Assemble

Optimized strategies for assembly are provided in SDT through the fe_caseg Assemble command. More details are given in section 4.8.8.

StressCut

The StressCut command is the gateway for dynamic stress observation commands. Typical steps of this command are

• View mesh generation, see section 4.7.1.
• Generate a selection sel=fe_caseg('stresscut -selout',VIEW,model);
• Display the selection in feplot using fe_caseg('stresscut',sel,cf)
• Observe the result using curve=fe_caseg('StressObserve',cf.sel(2),def)

For the selection generation, accepted options are

• VIEW can be a mesh so that feutilb Match is used find elements associated with viewing positions. A structure struct('type','Gauss') to return selection at Gauss points. A structure struct('type','BeamGauss') to return selection at beam Gauss points.
• a model or feplot handle cf can be provided as third argument.
• -SelOut requires selection output.
• -Radiusval provides a search radius for the feutilb Match call.

The sel data structure is a standard selection (see feplot sel) with additional field .StressObs a structure with the following fields

• .cta observation matrix for stress components. The expected sort is to have all components at first node, all at second node, ...
• .DOF expected DOF needed for the observation.
• .X,.Xlab labels for the observation, see Multi-dim curve for details.
• .CritFcn callback to be evaluated, see fe_stress CritFcn.
• .Node,.Elt nodes and elements for the view mesh.
• .trans structure for the observation of interpolated displacement (needed when view mesh nodes are not nodes of the original mesh).

StressObserve

The StressCut command typically returns all stress components (x, y, and z), for a relevant plot, it is useful to define a further post-treatment, using the sel.StressObs.CritFcn callback. This callback is called once the stress observation have been performed. The current result is stored in variable r1, and follows the dimensions declared in field .X of the observation. For example to extract stresses in the x direction, the callback is

 sel.StressObs.CritFcn='r1=r1(1,:,:);';

The StressObserve command outputs the stress observation in an curve structure. You can provide a callback -crit "my_callback". The command option -trans allows observation of translations for selections that have this observation. If empty, all components are kept.

data=fe_caseg('StressObserve -crit""',cf.sel(2),def);
iiplot(data); % plot results

ZoomClip

The command accessible through the axes context menu Clip, can now also be called from the command line fe_caseg('ZoomClip',cf.ga,[xyz_left;xyz_right]).