Mac & PC

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Introduction

At a glance

This explains:

• The dialog that first appears when the application starts, and then the main dialog.
• The general operation of the application. Number input and editing and ancillary text files are described.

The introductory dialog

Inch-pound or metric

The dialog that first appears when the application is started offers a choice of three measurement unit systems:

• The inch pound system sometimes also called customary units. The maximum dimension is 320 inches or 26’ 8” and the resolution is 0.01 inch.
• Metric units with large dimensions. The maximum dimension is 32 metres and the resolution is 1 mm.
• Metric units with small dimensions. The maximum dimension is 3.200 metres and the resolution is 0.1 mm.

At any particular time the application works wholly with one system and there are no facilities for converting data from one system to another.

The choice of a unit system will cause the introductory dialog to be replaced by the main dialog where a description of an example cross-section that illustrates the chosen measurement unit system is displayed. That example can be modified to suite the user’s purpose and then the file saved with a file name determined by the user.

File open facility

With the introductory dialog the main menu Files “Open” item is enabled allowing the user to open a file of a previously prepared cross-section description. This also causes the introductory dialog to be replaced by the main dialog.

The main dialog

The main dialog has a traditional style main menu at the top with pull-down sub-menus.

The body of the dialog contains four list boxes where the names of various entities are displayed.

Across the bottom is a status bar where from time to time information is displayed.

Nothing on this dialog can be changed by the user. The lists are intended to allow the user to select an item. Facilities for various actions are provided in the menus.

Four kinds of entity and entity names

There are four kinds of entity; a material, a component, a load-case and a time affect set. Each entity has a name, determined by the user. The main dialog includes a list box for each entity kind where the entity names are listed.

Material: A material entity describes a material such as concrete, or mild steel.

Component: A component entity describes a part of the cross-section. Each component is either a shape component or a point component. Typically concrete is a shape component and an arrangement of steel bars is a point component.

Load–case: A Load-case entity describes a state of the cross-section that is of interest. Such states are such as the ultimate strength, the first yield of a mild steel bar or a given bending moment.

Time affect set: A Time affect set has provision for a shrinkage value and a creep coefficient for each component and the name of the load case that causes the creep.

Entity names can be up to twenty characters including spaces between words. The names can have practical meaning. The edit dialog for each entity kind includes a text edit box for the name and automatic facilities that ensure each name is unique within each entity kind.

The main menu has an item for each entity kind that includes “Add”, “Copy’, “Edit” and “Delete” menu items. The “Copy”, “Edit” and “Delete” require that an entity in the list is selected. A single click of a pointing device on an entity name will select it. A double click will have the same affect as the “Edit” menu item: it opens the editor for that entity. There is a known bug with this double click in that it does not always open the right entity.

Mac & PC

General operation

Number input and editing

A text edit box is provided for each number to be input, or that may be changed by the user. Each such edit box can be given the focus by a “left click” of a pointing device when the pointer is on it. While such an edit box has the focus text characters can be made to appear in it by such as a keyboard. The focus is removed from such an edit box when the focus is given to another feature on the screen. Other features include other text edit boxes and buttons.

Any action by the user that would remove the focus from an edit box causes an automatic check on the validity of the contents of that box. If that contents does not represent a valid number an error condition is created. The background color of the edit box is changed to yellow and all the other edit boxes, buttons etc are disabled. In this error condition only the content of the offending yellow edit box can be changed. However, one changed in this offending yellow edit box will cause all the other edit boxes and buttons etc to be enabled again.

Some number edit boxes have an exponent immediately to the right. Generally there is “x10” on the same background color as the general background color outside the edit box and an exponent such as “-3″ or ” 6″ on a rectangular background the same color as the background inside the edit box. A left click on the exponent will lead to a dropdown list of alternatives that may be selected as the exponent.

In instances where the exponent happens to be zero the “x10” is not visible and the rectangle for the exponent is blank. Nevertheless this rectangle is visible being of a different color from the general background. A left click on this rectangle will lead to the dropdown list of alternative exponents. This list includes blank that means a zero exponent.

Where metric units are in use the “x10” and the exponent are replace by the metric prefixes “k”, “M”, etc. on a rectangle of that different color, and similar facilities for a dropdown list of the alternatives.

Table edit dialogs

The component edit dialogs and the material edit dialog (with Properties as described selected) have a button labeled “…. table” that leads to a table edit dialog. The table consists of lines of cells. Generally one cell has the focus indicated by a blue colour.

The focus can be moved to another cell by a click of a pointing device, or the arrow keys on a keyboard.

The cell that has the focus will change to an edit mode:

• By a click of a pointing device on the focused cell
• By the Enter key.
• By any key on a key board representing a printable character. However, the character will replace the whole content of the cell.

In this mode the content of the cell can be edited by a keyboard; the horizontal arrow keys moving a cursor within the cell.

A cell will be taken out of the edit mode:

• By a click of a pointing device on any other cell or a button on the dialog.
• By the Enter key.
• By either the up or down arrow keys.

Any of these actions will provoke a check on the validity of the contents. If it is not valid an error condition is created. A text edit box with the invalid contents appears above the table along with an OK and a Cancel button. Also everything on the dialog is disabled except that text edit box, the associated Cancel button and the main Cancel button below the table. If the content of the text edit box is changed to be valid the associated OK button is also enabled. That OK button will cause a return to the normal table mode with the new value in the offending cell.

Near the bottom of the dialog are buttons labeled “Insert new line” and “Delete line”. The “Insert new line” button will cause a new line to appear below the line with the focused cell and the focus moves to a cell in the new line.

The “Delete line” button deletes the line with the focused cell. The focus moves to a cell in the line above.

The top line cannot be deleted and it is not possible to insert a new line above the top line.

Graphics

The application can display a graphical representation of the cross-section and of the stress/strain relationship of each material. These displays can not be changed: they simply represent the data at the time a “Display” menu item is clicked. The dialogs for these displays are non-modal so that other facilities in the application can be used while the display remains on the screen. However the displays are not updated if the data they represented is changed.

Main menu Load cases includes a Display item that leads to a dialog that displays the whole cross-section. Note that this is disabled unless there is at least one load case. The reference axis of the current load case is shown in blue. All the points in the point components are shown as black circles of a size consistent with the cross sectional area in the point component description.

Main menu Materials includes a Display item that leads to a dialog that displays the stress/strain relationship of a material. If the material is of material kind “concrete” the display has negatively increasing stresses up and negatively increasing strains left to right and the ultimate compressive strain is indicated in blue. If the material is of material kind “steel that yield” the yield tensile strain is indicated in blue.

 “Display as text” button

The edit dialogs for each entity kind includes a button labeled “Display as text”. This leads to a further dialog that displays a complete description of the entity as one text document. This display is not editable. It is text limited to ASCII characters 10, 13 and 32 to 126.

There is a “save as” button that leads to a standard save as dialog. The saved file is text intend to be read by a text editor application. A text editor application that is able to use a hard-copy printer is envisaged so that a hard copy of the cross-section details can be produced.

If the type font used with these files has a fixed character width then tables of numbers will appear in columns. Also in tables there is a comma on each line between each column. These commas are intended to assist in the use of the table facilities that are provided in some text editor applications.

Unfortunately a fixed character width type font is not available within this application so that columns are not well presented in the dialog on the computer screen.

The xseckeep.txt file

The Windows version makes minimal use of the registry.

The application uses the home path of the application’s writable scratch directory or storage where it puts a file called “xseckeep.txt”. On startup it looks for this file and if it does not find such a file it continues the session using default values for the information the user might expect it to remember from a previous session. On closing a session it writes such a file.

This is completely automatic and the user need not be aware of the xseckeep.txt file.

On the Windows computers used for testing so far, one running Windows 7 and two running Windows 8 the home path was:

<C:/Users/user/AppData/Roaming>

On an Apple MacBook running OS X 10.10 the home path was:

<Macintosh HD/Users/user>