# Example Problems

This example manual provides several example problems. Every example problem is explained in detail; Creating analysis model in GiD, Generating Impact input file, Running input file in Impact then Visualisation results.

Cantilever plate | Colliding cylinders
An impactor hits vertically at the tip of a cantilever Aluminium plate (100mm x 50mm) with a thickness of 2 mm, fixed at one end. The impactor has a constant velocity of 3 m/s. Simulation time: 15 ms. | A steel cylinder (1 mm thickness, radius 20 mm, length 200 mm) is fixed in both ends. Another cylinder (the same geometry and material) in 90 deg orientation is colliding the fixed-end cylinder. The motion of cylinder is in the direction of x-axis with the velocity of 10 m/s. Simulation time: 20 ms.

### Problem case 1: Cantilever plate

#### Plate geometry Modelling

Activate coordinate tool:

- Utilities > Tools > Coordinates windows

- Geometry > Create > Point

Entering point data:

- In coordinates window: (0,0,0); (100,0,0); (100,50,0) and (0,50,0)

- Click to fit view

- If you want to see the label you can use button to enable and disable labels

Create lines:

- Click the button to start defining lines

- Right click, the select Contextual > Join, or you can use a shortcut Ctrl+A

- Create lines by clicking the corresponding nodes. Once you have finished, just click [Esc] to complete drawing lines

Creating surface:

- Click to define NURBS surface

- Start clicking the lines. After completed all four lines, click [Esc] button to complete the operation

#### Impactor geometry modelling

Drawing in different layer:

- The impactor will be drawn in different layer. Click the button. A layer window will appear

- Click button, you will see layer 1 is created

- You can hide and show layers by clicking button

- Now hide layer 0 by clicking next to layer 0

Drawing impactor:

- Utilities > Tools > Coordinates windows

- Geometry > Create > Point

- In coordinates window: (100,0,10)

- From the standard bar, find and click it. This will open copy dialog where translation and rotation ob objects can be done from here.

- Rotation of the point and extruding to create line should be performed

- Click Select button then click the point that you want to rotate (point 5), then click finish

- Change the angle to -90, and do the same thing

- From the standard bar, click again

- Lines 5 and 6 should be translated 50 mm. While translating, the lines extruded into surfaces. Click Select button, click lines 5 and 6, then click Finish button

- Now you have a complete geometry drawing plate and the impactor. If you show all layers, and show in render (Right click, Render > Smooth), also use transparent view (click button in layer dialog), you should get this image:

#### Finite Element Meshing (plate, layer 0)

- Show layer 0 (plate) only and hide layer 1 (impactor), use to show/hide layers

- If you are in Render mode, turn it back to Normal mode (Right click, Render > Normal)

- If the surface is not clearly visible, you can rotate (), or from the menu View > Rotate > Plane XY(original) then fit view ()

- Define quadrilateral element, Mesh > Element type > Quadrilateral

- Select the surface by clicking the surface (indicated by pink color). When you click the surface, the color will turn red, which means selected. Press [Esc] to finish selection

- Mesh > Structured > Surfaces > Assign number of cells, then select the surface by clicking the pink line, then press [Esc]

- A window popped up, enter number of cells assigned to lines: 15, press Assign button

- Click one of long edge line (blue color). When you click, it turns to red (also the opposite line), then press [Esc]

- A window popped up again, enter number of cells assigned to lines: 6, press Assign button

- Click one of short edge line (blue color). When you click, it turns to red (also the opposite line), then press [Esc], then press Close button

- Mesh > Generate mesh , or you can you a shortcut Ctrl+G. If a dialog asking the old mesh will be erased, just press OK button to continue

- You are requested to enter the size of elements. Ignore it, press OK button. Element meshing will be generated, click View mesh button

- If you want to see the element and node labels, use the toggle icon label

#### Finite Element Meshing (impactor, layer 1)

- Show layer 1 (impactor) only and hide layer 0 (plate), use to show/hide layers

- You will see the impactor already meshed. This is generated automatically, without your control. We are going to control instead of using the automatic generated mesh

- If the surface is not clearly visible, you can rotate (), or from the menu View > Rotate > Plane XY(original) then fit view ()

- Define triangular element, Mesh > Element type > Triangle

- Click the two surfaces (indicated by pink color). Every time you click the surface, the color will turn red, which means selected. Press [Esc] to finish selection

- Mesh > Structured > Surfaces > Assign number of cells, then select both surfaces, then press [Esc]

- A window popped up, enter number of cells assigned to lines: 5, press Assign button

- Click one of curve line (blue color) of the first and the second surfaces. When you click, it turns to red (also the opposite line). To finish the selection operation press [Esc]

- A window popped up again, enter number of cells assigned to lines: 3, press Assign button

- Click one of the straight lines (blue color). When you click, it turns to red (also other straight lines), then press [Esc], then press Close button

- Mesh > Generate mesh , or you can you a shortcut Ctrl+G. If a dialog asking the old mesh will be erased, just press OK button to continue

- You are requested to enter the size of elements. Ignore it, press OK button. Element meshing will be generated, click View mesh button

#### Material definition (plate, layer 0)

- You have to make sure that you have activated GiD to Impact interface (Data > Problem type > Impact)

- Show layer 0 (plate) only and hide layer 1 (impactor), use to show/hide layers

- Data > Materials > STANDARD MATERIALS, select ALUMINUM 2024 T3, and change the thickness to 2.0

- Click Assign > Elements, select all elements (left click and drag to cover all elements), the selected elements turns to red color, then press [Esc] to finish the selection process

- If you want to see the plate has been assigned with material, Data > Materials > STANDARD MATERIALS then click Draw > All materials. Click Finish button to finish viewing materials

#### Material definition (impactor, layer 1)

- Show layer 1 (impactor) only and hide layer 0 (plate), use to show/hide layers

- Data > Materials > CONTACT ELEMENT ONLY, select CONTACT TRIANGLE 1, and change the thickness to 1.0. The contact zone extends to half the thickness on each side of the element

- Click Assign > Elements, select all elements (left click and drag to cover all elements), the selected elements turns to red color, then press [Esc] to finish the selection process

- If you want to see the plate has been assigned with material, Data > Materials > CONTACT ELEMENT ONLY then click Draw > All materials. Click Finish button to finish viewing materials

#### Boundary Conditions (impactor, layer 1)

- You are still working in layer 1, Data > Conditions

- Click Assign button and select all nodes

#### Boundary Conditions (plate, layer 0)

- Show layer 0 (plate) only and hide layer 1 (impactor), use to show/hide layers

- Data > Conditions, select ID 2 and set all 0 for fixed constraints

- Click Assign button and select the nodes to be constrained

#### Simulation settings

- Set simulation time to 15 ms, Data > Problem Data > TIME CONTROL

#### Tracker control point

- To monitor a specific node, you can use this Impact feature; Data > Conditions, select Tracker point. The file will be saved in Impact directory, not in GiD directory

#### User information

- For a better record, you can save user information; Data > Problem Data > TITLE

#### Create Impact input file

- File > Export > Calculation file, change Files of type: All files(*), enter the file name: example-1.in, then press Save button

#### Running Impact input file (example-1)

- Open Impact program. If you are in Windows, run ImpactGUI_*.bat. If you are in Linux, run ImpactGUI_*.sh

- Click Processor tab, load Impact input file from the folder that you save example-1.in by clicking button

- Run this file by clicking button

#### Viewing results using Impact Post Processor

- Click the Post processor tab in Impact window, then click

- Go to the directory where you save example-1.in, Files of type: Open solver result (*.res)

- Select example-1.in.flavia.res and press Open

#### Plotting results using Impact Graph

- Click Graph tab in Impact window, then click

- Go to Impact directory and select the tracker file: plate-disp.trk and press Open. You will see the displacement history of the node that you have selected

- To add new charts (intensity stress history) from res file, click select STRESSES(I), enter number of elements 60-63 (it means: 60, 61, 62, and 63). Now you can compare them

#### Viewing results using GiD Post Processor

- In GiD, click icon, from the menu Files > Open, select example-1.in.flavia.res and press Open. The results will be loaded in GiD

- Click deformation icon and set the magnification factor 1.0

- Click contour fill icon then select DISPLACEMENTS > |DISPLACEMENTS|

- Animation can be shown from the menu Window > Animate, and click play button

#### Plotting results using GiD Post Processor

- Click point evolution icon

- Select LOCAL STRESSES > TypeSHELL BT4 >Sxx-LOCAL STRESSES. Select the element of interest (at the tip of the plate)

### Problem case 2: Colliding cylinders

#### Geometry Modelling Cylinder 1

Create points

- Activate coordinates windows: Tools > Coordinates windows

- Create point: Geometry > Create > Point. Then using the coordinate windows dialog, define poins: (20,0,0) and (20,0,200)

- To see all points in your screen, you can fit view by pressing icon. If you want to rotate, you can use

- If you want to see the label of the points, you can use button. You should see the points you have created

Create line

- Click create line button , then click right button of your mouse, select Contextual, then select Join or Ctrl+A

- Click point 1 then point 2 [Esc] [Esc]. You will see a line has been created

Create surface

- Click the copy/transform button , a copy dialog appears. Make sure Entity type: Lines, and Transformation: Rotation

- Enter Angle: 180

- Define the rotation axis. In the first point, leave it (0,0,0), In the second point, set to (0,0,1) Select Do extrude: Surfaces

- Click Select button then click the line, [Esc]. You will see a surface is generated, which is half of the cylinder

- Change the Angle data to -180, and do the same thing as before. You will create another surface so you have created a complete cylinder

- You can see the cylinder, if you see in rendered, right click and select Render > Smooth. If you want to see in normal (unrendered), do the same but select normal

#### Geometry Modelling Cylinder 2

Create point

- Select layer icon , since we want to draw the cylinder in different layer (layer 1), then click in the layers dialog. You will see layer 1 is created.

- Activate coordinates windows: Tools > Coordinates windows

- Create point: Geometry > Create > Point. Then using the coordinate windows dialog, define points: (30,0,100), (30,100,100) and (30,-100,100)

Create line

- Click create line button , then click right button of your mouse, select Contextual, then select Join

- Using the same method as in cylinder 1, create two lines

Create surface

- Click the copy/transform icon , a copy dialog appears. Make sure Entity type: Lines, and Transformation: Rotation

- Enter Angle: 180

- Define the rotation axis. In the first point (50,0,100). In the second point, set to (50,1,100)

- Select Do extrude: Surfaces

- Click Select button then click the two line, [Esc]. You will see two surfaces are created, which is half of the cylinder

- Change the Angle data to -180, and do the same thing as before. You will create two other surfaces

- If you render, then you see two cylinders have been created, one in layer 0 and another one in layer 1

#### Meshing Model

Cylinder 1

- Hide object in layer 1

- Mesh > Structured > Surfaces > Assign number of cells, then try to control your meshing, for example the cross-section divided into 20 cells and along the cylinder divided by 12 cells

- Mesh > Element type > Quadrilateral, then select the surfaces

Cylinder 2

- Now show object in layer 1 and hide object in layer 0

- Do the same thing to define the meshing

- Define all surfaces for Quadrilateral elements

- Show all layers

- Mesh > Generate mesh (or Ctrl+G)

#### Analytical Model

Cylinder 1

- Assign material Elastoplastic 1 (Data > Materials > GENERAL ELASTOPLASTIC) to all elements of cylinder 1

- Assign boundary conditions fixed (all 0) to both ends, from the menu Data > Conditions, Boundary Conditions P. Use ID 1

Cylinder 2

- Assign material Elastoplastic 2 (Data > Materials > GENERAL ELASTOPLASTIC) to all elements of cylinder 2

- Assign boundary in one end, velocity-x: -10, velocity-y: 0, velocity-z: 0. Use ID 2

#### Simulation settings

- Set the simulation time 20 ms, Data > Problem Data > TIME CONTROL

- For a better record, you can save user information; Data > Problem Data > TITLE

#### Create Impact input file

- File > Export > Calculation file, change Files of type: All files(*), enter the file name: example-2.in, then press Save button

#### Simulation in Impact

- Run IMPACT program

- Click Processor tab, then open the IMPACT input file example-2.in (using )

- The input file will be loaded in the editor box. You can edit your file here and save the modification, if necessary

- Run the input file using the start button

#### Viewing Results in Impact Post Processor

- Click to Post Processor tab

- Open result file , files of type: Open solver result (*.res), select example-2.in.flavia.res

- By changing the simulation time, you can see the results at 0 ms, 5ms and 10 ms

At 0 ms

At 5 ms

At 10 ms