How To…

How to import a mesh?
How to import a file?
How to define & update a property set?
How to define & update a boundary condition (BC) set ?
How to assign properties, boundary / initial conditions to a mesh?
How to navigate - zoom and pan?
How to move a node?
How to translate selected nodes of a mesh?
How to draw a mesh?
How to save the screen as an image?
How to define output history points?
How to use the anisotropy option?
How to export and execute a file?
How to use keyboard shortcuts?

How to import a mesh?

Y-GUI V2.0 is capabel of importing two mesh formats: Y2D format and Phase2 (.fea and preferably without joints, etc.). Once you have such a mesh file, simply import it either from File menu --> Import Mesh or specify the filename in the File to Import textbox and then press Import Mesh button.


How to import a file?

A Y2D input file (.y) can be fully imported. This function imports the mesh, as well as all the data of the file including the control database, interaction database, property and boundary condition sets and initial conditions. To import a mesh either select File Menu --> Open Y File or indicate the filename in the File to Import textbox and then press Import Whole File Button.


How to define & update a property set?

Material properties such as Young's Modulus, Poisson's ratio, friction coefficient, density, shear / tensile strength and fracture energy as well as numerical parameters including viscous damping, contact penalty, and refinement index can be easily enterd using the Properties tabpage. For ease of use, you can assign names to the pr. sets (in the Property Set combobox). Once that all the required parameters are typed, and the type of property set is chosen, you can also pick a color for the property set and finally press Add Property Set to add the current set to the internal database of the program.


Once this button is pressed, a table of all saved pr. sets will be displayed one the right-hand side of the page.


If at a later point you wish to modify / update certain values of a property set, simply select it from the Property Set combobox, make necessary changes and finally press Update Selected Property Set. This will update the pr. set in the internal database of the program as well as on the table.

To learn more about the properties, refer to the Y2D Code page.

How to define & update a boundary condition (BC) set ?

Boundary condition sets are added almost the same way as property sets. Define the type of boundary condition in x- and y-directions either as force, acceleration or velocity and then enter their corresponding values. You can also specify element surface pressure / traction. Agian, you can assign name to BC sets (in Boundary Condition Set combobox) and pick color for the set. Once that the Add Boundary Condition button is pressed, the current settings will be added to the internal database of BC and also displayed in a table on the right side of the page.


Note that, you can turn on / off each BC set through their allocated checkboxes. This is useful if for example all the nodes of the mesh have the same BC which might make the graphical representation a bit messy.

BC sets can be updated exactly the same way as property sets.

How to assign properties, boundary / initial conditions to a mesh?

Once that property & BC sets are added, they can be assigned to the elements nodes of a mesh that has already been imported. To assign Property Set to elements of a mesh, first press the 'Pr' option in the right-hand side toolbar of the Graphics page (Fig. 1 below). Then, select the desired elements one by one or draw a rectangle around them (Fig. 2 below); the selected elements will be highlighted. Then, right click select, Assign Property and finally select a property set from the combobox (Fig. 3 below). When you are done with the assignments, right click select Done! or press E on your keyboard (Fig. 4 below). See the four screenshots below to graphically follow this procedure.

Fig. 1
Fig. 2
Fig. 3
Fig. 4

To assign boundary / initial conditions to the nodes of the mesh, select 'BC' or 'V0' on the toolbar, respectively and then select the desired nodes the same way as selecting elements. You can then assign a BC set to the selected nodes similar to how you assigned pr. sets to elements, i.e. right-click, select Assign Boundary Conditions and then select the desired BC set from its combobox. If the assinged BC in x- or y-direction is non-zero, a vector will be shown in the graphics page for on the assigned nodes (note that it is not currently scaled according to the magnitude of applied force / acceleration / velocity).

When assigning initial conditions, right-click select Assign Initial Conditions --> Current Nodal Velocity (this is the only initial condition available now!). This will bring an input box where you can enter the velocity in x- and y-directions. This procedure is shown in the figure below:


While selecting nodes or elements, you can cancel the selection (and the current action) by either pressing theEscape button on your keyboard or right mouse clicking and selecting Cancel current selection.

You can also deselect nodes and elements by pressing the Control key and selecting the desired nodes / elements (one by one or drawing a rectangle around them).

You can also select all nodes / elements of a mesh by pressing Control + A simoultaneously.

Note: When selecting nodes, there is always some snap distance that will help you pick the nodes more easily. Each time you import a mesh, this snap distance is updated automatically to best count for the dimesions of the model. However, in many cases this distance might not be optimal, esp. when you have a fine mesh for which picking a single node might be difficult. To overcome this problem, you can always modify the snap distance. To find out the default snap distance, press "Shift + N" in you keyboard and its value will be displayed in the Messages Window. To increase or decrease this value, press "Shift + _" or "Shift + +" on your keyboard, respectively.

How to navigate - zoom and pan?

There are various options available to navigate in the graphics. They are provided through the toolbar, trackbar, and panning buttons of the graphics page and also the middle mouse button. The options provided in the Graphics pages are shown in the picture below:


The toolbar buttons enable you to zoom in, zoom out, zoom to the extents, and refresh the view. You can also do directional panning by the four buttons available (see the above figure). Also, the trackbar enables you to zoom in / out the mesh rapidly.

A nice feature of the Y-GUI V2.0 is dynamic zooming and panning through the mouse wheel (middle mouse button). Simply, scroll the mouse wheel to zoom in and out. Also, click and drag the mouse wheel to pan dynamically. These options make it very fast to navigate inside the mesh.

How to move a node?

A mesh node can be easily moved to a new location. Simply, select the move option of the toolbar in the Graphics page. Then, select the desired node. This will pop up a new window where you can set the new location of the node (x,y). Alternatively, you can click for the new location. Note that when you move the mouse on the screen the x,y written in the popped-up textbox will be updated to show the current location of the cursor. The whole moving procedure is showin in the figures below:



How to translate selected nodes of a mesh?

Selected nodes of a mesh can be translated along the x- and y-axis. To do this, first select translate option () in the toolbar of the Graphics page and then select the desired nodes (or press Ctrl + A to select all). When nodes are selected, a new window will pop up where you can input the translation distance (dx,dy) in drawing units. Press the Enter key of the keyboard or the Apply button to finalize the translation.


How to draw a mesh?

A tool has been included in Y-GUI V2.0 to manually draw simple meshes. This is especially helpful when you have already a complicated mesh and you need to add some elements to it or when you want to set up a simple model.

Important Note: The nodes of the manually drawn mesh MUST be added counter-clockwise. Otherwise, the elements will have negative volume and the Y2D simulator might crash and will produce meaningless results.

To manually draw a mesh click on the Manually add mesh option (+) on the toolbar of Graphics page. Then, either click for the location of the nodes or enter their coordinats in the newly shown window. Once that three points are inserted, an element will be drawn and added to the program's database. Also, note that the drawing bounds will be refreshed automatically in order to centre the whole drawing in the graphical canvas. If you click close enough to the existing mesh nodes, they can be used as nodes of the new mesh (do not forget to adjust the snap distance if needed, as explained above!). Once finished, right-click select Done! or press E. This procedure is shown in the pictures below:

drawMesh1 drawMesh2 drawMesh3 drawMesh4 drawMesh5 drawMesh6 drawMesh7

How to save the screen as an image?

You can save the contents displayed on the graphical canvas as an image in Bitmap (.bmp), JPEG (.jpg) or GIF (.gif) format. To do so, press the Save Screenshot button in the Graphics page and specify the filename.

How to define output history points?

Output history points can be used to monitor certain state variables for specific elements. To define output history points, simply right-click select Define Output History Points. Then select the desired state variable (e.g. xx-stress or velocity) and insert the point at the location you wish to by either a click or entering the coordinates (x,y) of this point. See screenshots below:


How to use the anisotropy option?

You can randomly assign property sets to selected or all elements of a mesh following a given distribution of pr. sets. This can count for the material anisotropy found in natural rocks / soils. Therefore, Y-GUI V2.0 has an option were you can assign the percentage of each property set (i.e. material distribution). This is done in the Anisotropytabpage. When the summation of percentages adds up to 100, you can go back to the Graphics page and start selecting the desired elements (click on Pr in the toolbar). Once done selecting, right click choose Assign Property--> Random Assignment. This will randomly assign pr. sets to the selected element considering the distribution defined in Anisotropy page. You can then go back to the Anisotropy page to see what is the actual used percentage of each property set. See below for details:


How to export and execute a file?

Once that you have imported a mesh, defined property / boundary condition sets and have assigned them to the elements and nodes of the mesh, and defined output history points, you can export the current settings to a Y file (.y) and consequently launch the Y2D program. To export the file, either select File Menu --> Save as... or specify the filename in the Y-Input Path and Filename textbox at the bottom of the page (alternatively click on the button just at the right side of the textbox), then press Export Y Input File. This will export the current settings to a Y file. If any error occurs during this process you will be notified. In order to export and execute the file, press the Export AND Execute Y File button.


How to use keyboard shortcuts?

There are a number of keyboard shortcuts implemented. These will help you use the program more conveniently. Here is the list of shortcuts together with their functionalities:

Shortcut Function Applied to
Escape Cancels the current action / selection (equivalent to Cancel current selection of context menu) Any node / element selection or mesh manipulation*
E or Enter Finalizes the current action (equivalent to Done! of the context menu) Any node / element selection or mesh manipulation
Shift + N Displays the current snap distance in the Messages Window ---
Shift + _ Reduces the current snap distance ---
Shift + + Increase the current snap distance ---
Enter Accept input Popped-up windows to accept input
Ctrl + A Selects all nodes / elemets Any node / element selection
Ctrl + mouse click Deselect already selected node(s) / element(s) Any node / element selection

*Cancel does not cancel assignment of properties / boundary conditions.