Strand7 Snippets

Snippet #5: Open Result File Options

Result files dialog

To select a result file for opening in the Strand7 GUI, the Available result files dialog below is used. A result file can be opened by selecting it from the list and clicking the Open icon, or by double-clicking the file name in the list.

One of the icons at the top of this dialog is the Options icon. This icon opens the options page, which allows you to hide particular result cases from the result file. For example, for LINEAR BUCKLING analysis you can Hide negative modes.

The following image shows the Strand7 multi-view display of the buckling results for a short cantilever with a lateral load – both positive and negative buckling modes are calculated and listed in the result case dropdown list.

By setting Hide negative modes before opening the file, only the positive modes are listed, making it easier to post-process just the modes that are likely to be of interest (only the flange in compression is now shown to buckle).

Summary of options

Solver	Option	Notes
LBA	Hide unconverged modes	Note that eigenvector not converged cases are considered as converged if the buckling factor has converged.
LBA	Hide negative modes	In linear buckling analysis, a negative buckling factor means that a load reversal is required to produce that buckling mode. If a load reversal is not possible for the structure, the negative modes can be ignored.
NFA	Hide unconverged modes	Normally we require all modes to be converged, but unconverged modes can be selectively excluded in mode superposition, particularly if the unconverged modes do not contribute significantly to the response.
	Hide zero modes	A zero frequency usually indicates a free body response (i.e., a rigid body mode where the structure, or part of the structure, is moving without deforming). Zero frequencies are expected in the natural frequency analysis of unrestrained structures (in a 3D unrestrained structure there will be six zero frequencies). The modes corresponding to zero frequency are not usually relevant to dynamic analysis, so they can be hidden.
	Hide modes with mass participation below %	This option hides modes with mass participation below a set value, enabling the post-processing to focus on the modes that contribute the most to a mode superposition result (such as harmonic or spectral response).
SRA	Hide modal results	Modal results are always stored in the spectral response result file, but usually we are interested mainly in the SRSS and/or CQC results, which are produced by combining the modal results. By hiding the modal results, the number of result cases in post-processing is significantly reduced, making it easier to focus on the combined results of interest.
NLA/QSA/NTA	Hide unconverged results	As long as an unconverged result does not influence a subsequent result, it may be acceptable to ignore those unconverged results, particularly unconverged intermediate sub-steps.
NLA/QSA/NTA	Hide intermediate sub-steps	All of these solvers allow for automatic sub-stepping to help achieve convergence. These automatic sub-step results can be optionally saved in the result file. If they have been saved, but are not necessary for post-processing, they can be hidden.