Oasys GSA 8.1 Release Notes

Contents

• Status
• New Features
  • Steel Design to AISC LRFD3
  • RC Slab Enhancements
  • COM Automation
  • Import and Export of GSA Data
  • Analysis Tasks
  • Conjugate Gradient Solver
  • Analysis Envelopes
  • Interface Enhancements
  • View Lists
  • Batch Printing of Views
  • Enhancements to Loading
  • Version Checking

A complete list of changes and fixes in this version is given in the GSA 8 Change Log.

Status

The solvers and pre- and post-processors have passed the verification procedures.

Changes to the format of the GSA binary data file (GWB file) in GSA 8.1 mean that, in most cases, GWB files saved in GSA 8.1 cannot be read by GSA 8.0 and earlier. GSA text files (GWA) can be read by earlier versions though references to data that are new to this version will be ignored.

New Features

Steel Design to AISC LRFD3

Steel design implemented to AISC LRFD3 for I, H, CHS and RHS sections.

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RC Slab Enhancements

RC Slab additional design codes:

• The following design codes may now be selected from which RC Slab will draw code dependent input and derived data: BS8110, BS5400, Hong Kong Code of Practice, EC2, ACI318, AS3600.
• If EC2 is chosen as the design code, then a specific country may be selected in order that the concrete's uncracked design strength and tensile strength may be derived using appropriate country-specific factors. These country-specific factors are stored in a Nationally Determined Parameters data file.
• An increased number of RC Slab's input and derived data parameters may be overridden by the user.
• Minimum areas of reinforcement may now be specified for each reinforcement direction in each face.

RC Slab Graphic View enhancements:

• 'RC slab reinforcement, top' and 'RC slab reinforcement, bottom' diagrams are now available. Lines are drawn of length scaled according to the area of reinforcement, oriented in the direction of the reinforcement.
• When an RC slab reinforcement option is selected for display by contours, contour values are initialised to values equating to standard bar sizes and spacings.
  When the model units are imperial contour values equate to bar sizes #4, #5, #6 and #8 at 8" and 6" c/c; otherwise contour values equate to bar sizes T12, T16, T20 and T25 at 200mm and 150mm c/c.
• When RC slab reinforcement is displayed, whether as diagrams or contours, the legend now reports the reinforcement angles and concrete and steel strengths, but only if these are the same for all elements drawn.

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COM Automation

The COM Automation interface has been extended to include the following options:

• Creation of new GSA models.
• Setting GSA data directly from a spreadsheet.
• Interrogating the GSA data.
• Extracting data from GSA.
• Extracting derived output, including combined and enveloped results.
• Printing saved and preferred views (see Batch Printing of Views).
• Saving saved and preferred Output Views to TXT (tab delimited), CSV or HTML file.
• Saving saved and preferred Graphic Views to WMF, PNG or JPG file.
• Functions for extracting case details.
• Functions for interpreting GSA lists.

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Import and Export of GSA Data

Various features have been implemented to facilitate the importing and exporting of GSA data. These are in addition to the previously existing capability (e.g. copy and paste in Table Views and copy in Output Views). These new features are summarised as follows:

• Individual modules or all input data can be copied from the Gateway onto the clipboard in text format, GWA syntax.
• Text in GWA syntax can be pasted from the clipboard to the Gateway. Geometry, properties and other records that are identified by number overwrite existing records. Constraint and loading records append to existing records.
• The Gateway ‘Paste Special’ command allows the user to select which GWA data on the clipboard is to be pasted and to specify whether to overwrite or append existing data. When appending, node numbers, element numbers and load case numbers, and references to these, in the imported data are incremented to follow on from the existing data.
• The ‘File | Import | Text (GWA file)’ command allows the user to select which data in a GWA file is to be imported and to specify whether to overwrite or append existing data. (Append behaviour is as in the Gateway ‘Paste Special’ operation.)
• View settings for Graphic Views and Output Views can be copied from the Graphic Settings and Output Settings wizards, respectively, onto the clipboard in text format, GWA syntax.
• View settings in text format, GWA syntax can be pasted into Graphic Views and Output Views either directly into the view or in the respective settings wizard, to result in that view being displayed.

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Analysis Tasks

The organisation of analysis case and analysis task definition data has been rationalised and access to this data has been improved. This is to enable the editing of the full content of analysis definition data. In achieving this analysis tasks have been given greater prominence than in previous versions of GSA.

An analysis task is a set of parameters that fully control one pass through a solver. An analysis task will often identify several analysis cases each of which, in turn, contains case specific parameters. An analysis task is defined by one pass through the Analysis Wizard.

The Analysis Cases table has been replaced by the Analysis Tasks view. In this, tasks are represented by nodes on a 'tree control' and cases associated with each task are represented by branches from the respective node. The right-click menu offers context related commands, depending on whether a task or case is clicked on. For instance, right-click on a task to access the command to edit that task or to delete the results for that task.

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Conjugate Gradient Solver (for static analysis of large models)

A conjugate gradient solver has been implemented in GSS. This solver allows much larger models to be analysed in GSA than was previously possible and may also speed up the analysis of large models.

As the conjugate gradient method is iterative, no factorization of the stiffness matrix is required and thus the sparsity of the stiffness matrix can be fully exploited. By itself the conjugate gradient method can be slow to converge so a pre-conditioner is used to improve the convergence rate. Three pre-conditioners are implemented in GSA:

• Richardson (equivalent to no pre-conditioner)
• Jacobi
• Line Jacobi (the recommended option)

To make use of this solver option it must be selected when creating or editing the analysis task. In the Analysis Wizard set up the analysis task as normal, but at the last page select the advanced option. On the "Stiffness Solution" page change the solution method from Active Column (the normal GSS solver) to Conjugate Gradient. This give the option of choosing the pre-conditioner, and as the solution is iterative the convergence tolerance and maximum number of iterations. Theoretically for "n" degrees-of-freedom the conjugate gradient solution should converge in no more than "n" iterations. With a pre-conditioner this number should be reduced but it will depend on the particular structure. As the number of iterations is a maximum it is recommended that this be set (approximately) to the number of degrees of freedom.

Calculation of element forces/stresses and reactions are unchanged in this solver.

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Analysis Envelopes

Analysis envelopes have been implemented. Results produced for a conventional envelope, as specified in the Combination Cases table, are calculated 'on-the-fly' by comparing the results for the permutations that make up the envelope to arrive at maximum and minimum values. For large models or envelopes that identify many permutations conventional envelopes can take a long time to be produced. An analysis envelope is produced in a batch operation and the results are stored for subsequent, rapid display.

'Analysis Envelopes' is a solver option available in the Analysis Wizard. The syntax of the case definition is as for a conventional envelope. The result type(s) for which the envelope is required must be selected and, for element results, whether just the 'worst value' or 'values at each node' must be selected. An analysis envelopes task sets up an analysis case for each of max and min results for each result type and for each position (i.e. worst or each node).

Internally the result for an analysis envelope for a given node or element is stored as the limiting permutation number. This is enough information for GSA to calculate, at the time of display, the result value. The case description associated with a permutation is described in terms of a standard (non-enveloping) combination case so the time taken by GSA to produce analysis envelope results at the time of display is the same as for standard combinations.

Analysis envelopes may be displayed in Graphic Views, both contoured and as diagrams, and in Output Views. In all cases the output is the max or min at the enveloped position plus values co-existent with this for the limiting permutation.

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Interface Enhancements

Various enhancements have been made to the user interface to Graphic Views and Output Views, as follows:

• Undo View and Redo View
  The new Undo View and Redo View commands allow multiple undoing and redoing of view settings. Each change to the view settings (e.g. rotate, zoom, labels, diagrams, contours in Graphic Views or data option, case list, by property in Output Views) adds an undo step to the undo buffer.
  Separate undo buffers are preserved for each Graphic View and each Output View.
• Copy and Paste of View Settings
  New copy and paste of view settings options allow view settings to be copied from one view to another and from one model to another.
• Dynamic Lists Toolbar
  The Lists toolbar automatically resizes to the width of the view, resizing the width of the cases and display comboboxes accordingly. This gives scope to display wide lists in wide views.
• Previous / Next Case and Display
  New toolbar buttons allow convenient stepping forwards and backwards through cases and display options.
• Sculpt Toolbar
  
  • All frequently used sculpt commands are now available on the new Command toolbar. On the Command toolbar is the Command combobox from which sculpt commands may be selected.
    The Command combobox is initialised with a list of commonly used sculpt options. However this list is dynamic in that the most recently used command is placed at the top of the list, whether the command has been picked from the Sculpt menu or from the Command combo box. Several 2D element sculpt commands are appended to the combobox list when 2D elements are present or added to the model. The selected command is then executed by clicking the Execute Command button on the toolbar.
    This new functionality allows rapid repetition of a sculpt operation and easier access to all sculpt commands used frequently within a session.
  • Whether the Command toolbar is displayed or not is registered across sessions. (I.e. It behaves as most other toolbars.)
  • The introduction of the Command toolbar has enabled a rationalisation of the Sculpt toolbar, resulting in fewer buttons on the toolbar.
• Incremental Defaults in Tables
  The following new increment operators available in Table Views copy the value from the same cell in the preceding record and perform an operation on that. They apply to numeric fields only.
  • +=f to add f to the copied value.
  • -=f to subtract f from the copied value.
  • *=f to multiply the copied value by f.
  • /=f to divide the copied value by f.
  If the increment, f, is omitted then the default value is used as the increment.

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View Lists

View lists have been implemented. A view list is a sequenced collection of preferred views and saved views. The main purpose of view lists is to enable a list of views to be printed in sequence and for that list to be preserved to allow the same list of views to be printed again later.

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Batch Printing of Views

Saved and preferred Graphic Views and Output Views can be printed without opening the view in GSA. The options are to print:

• a selected view,
• all views of a type (e.g. all saved Graphic Views),
• all marked views of a type (e.g. all marked Graphic Views),
• a selected view list,
• all view lists and
• all marked view lists.

The commands to invoke these options may be given either:

• from the right-click menu for the Views tab on the Gateway or
• remotely (i.e. without running GSA interactively) by COM Automation or by Command File.

Views and view lists may be marked for printing (and unmarked) from the right-click menu in the Gateway.

See also the new Graphic View 'Print by case' option.

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Enhancements to Loading

Enhancements to the specification and display of loading have been made, as follows:

• Gravity loads are now applied to a list of elements, defaulting to 'all' elements. This allows gravity loads to be split between different load cases to facilitate the consideration of adverse and beneficial loading.
• Gravity loads may now be displayed as diagrams.
  • Gravity loads on beam elements are displayed as 'Beam Loads, Force' diagrams.
  • Gravity loads on 2D elements are displayed as 'Face Pressures' diagrams. These include any additional mass specified in the 2D element property.
  • Gravity loads on mass elements are displayed as 'Node Loads, Force' diagrams.
  (All these diagrams are included in the 'All loading' diagram setting.)
• Wizards are now available for all loading modules. (Previously wizards were only available for grid loading.)
• It is now possible to delete all loads of a particular type or, indeed, all loading by right-clicking on the respective branch on the Tables tab of the Gateway.
• Most load diagrams in Graphic Views are now drawn in the direction of the load, by default. The 'Draw loads as components in output axes directions' option is offered on the Diagram Settings dialog to enable load diagrams to be broken down into components (i.e. to provide the functionality offered in earlier versions of GSA).
  Beam loads are always broken down into components in output axes directions.
• Graphic View animation can now animate by stepping through a list of cases. This is automatically invoked if, at the time of requesting animation, the Graphic View cases list identifies several load cases or several results cases (i.e. analysis cases and/or combination cases).
• In 'Split 1D Elements' and 'Connect 1D Elements' when 'Split loads and replace references to old elements with references to new' is selected, beam loading on old elements is now mapped onto the new elements. This overcomes the 'saw-tooth' load pattern arising from splitting an element with a linearly varying load applied.
• Sculpt options are now available for the creation of all load types. (Previously only grid loading could be created graphically.)
• When, in the sculpt 'Create beam load' command, a patch load is specified to extend beyond the end of the beam to which it is applied the load is automatically 'broken up' and applied to the string of beam(s) that are positioned to take the load, if they exist.
• The new sculpt options 'Map Node Loads', 'Map Beam Loads' and 'Map Face Loads' allow node loads, beam loads and face loads to be applied to selected nodes, 1D and 2D elements, respectively, with loading values expressed as a function of the position of the item being loaded.
  Normal mathematical notation is used in expressions. E.g. 'z + abs( sin(x) ) * pi'

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Version Checking

So as to help users ensure that they are running the latest software a new version checking system has been implemented. This compares each GSA executable file installed locally with the set that Oasys identifies as being the ‘current versions’. (The comparison is carried out locally; no data is transmitted to Oasys.) Executables for which updates are available are highlighted. Updates may then be downloaded from the GSA Downloads page.

Updates are provided either as revised individual executable files, offered in the ‘Patches' section of the Downloads page, or as a rebuilt installation that completely replaces the previous build.

This system enables rapid delivery of bug fixes and, occasionally, minor enhancements. All changes are recorded in the GSA 8 Change Log.

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A complete list of changes and fixes in this version is given in the GSA 8 Change Log.

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