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FEAProject-1.pdf
ME 4860/6860 Metal Forming
FEA Project‐1
Examine the effect of h/d ratio and friction on the compression of a cylinder
You have already done the simulations to cover the matrix of conditions below
Height(mm) Diameter (mm) h/d Friction Stroke 50 25 2 Coulomb Friction P = 0, 0.1, 0.3, 0.5
Shear Friction m = 0, 0.3, 0.6, 1.0 20
100 25 4 Coulomb Friction P = 0, 0.1, 0.3, 0.5 Shear Friction m = 0, 0.3, 0.6, 1.0
40
25 25 1 Coulomb Friction P = 0, 0.1, 0.3, 0.5 Shear Friction m = 0, 0.3, 0.6, 1.0
10
10 25 0.4 Coulomb Friction P = 0, 0.1, 0.3, 0.5 Shear Friction m = 0, 0.3, 0.6, 1.0
4
Each group will analyze the simulation results and write a report describing:
1. The effect of the h/d ratio Use 4 simulations to describe the effect of h/d on
a. Engineering stress‐strain curve b. and ⁄ where ln 1 where 0.4 is the engineering
strain at the end of deformation c. Shape of the deformed workpiece
2. The effect of fiction factor
Use 3 simulations to describe the effect of friction factor on a. Engineering stress‐strain curve b. and ⁄ where ln 1 where is the engineering strain at
the end of deformation c. Shape of the deformed workpiece
⁄ ⁄
The eleven groups of 4 students each (G1 through G11) will analyze the simulations per tables below. Each group will have to look at the results of 6 simulations
m mu 0.3 0.6 1.0 0.1 0.3 0.5 h/d h/d
0.4 G1 G1,G2 G1,G3 0.4 G4 G4,G5 G4,G6 1.0 G1,G2 G2 G2,G3 1.0 G4,G5 G5 G5,G6 2.0 G1,G3 G2,G3 G3 2.0 G4,G6 G5,G6 G6 4.0 G1 G2 G3 4.0 G4 G5 G6 m mu
0.1 0.3 0.5 0.1 0.3 0.5 h/d h/d
0.4 G7 G7,G8 G7,G9 0.4 G10 G10,G11 G10 1.0 G7,G8 G8 G8,G9 1.0 G10,G11 G11 G11 2.0 G7,G9 G8,G9 G9 2.0 G10,G12 G11,G12 4.0 G7 G8 G9 4.0 G10 G11
Introduction to Simufact.Forming
The software package you will be using for finite element modeling of metal forming is called
Simufact.Forming. It is installed on the computers in Room 152B and 152D. You will have access
to the software anytime the lab is open. As a reminder, the software is meant for academic
purposes only, and should not be used for other purposes.
Below is a figure from the introductory slides that I showed during the first day of class. Broadly
speaking, a metal forming system consists of
1. The workpiece, also called the billet or sheet
blank. It gets deformed during the metal forming
process
2. The tooling which apply the necessary forces
necessary to alter the shape to the workpiece. The
deformation of the tooling is primarily elastic.
3. The workpiece/tool interface where the
workpiece slides relative to the tooling, and in the case of hot forming operations, where
heat flows to or away from the workpiece.
4. The equipment (presses, hammers etc.) that provide the energy or force for the process
The following pages describes how you can set up a simulation for the deformation of a cylindrical
workpiece that is compressed between two dies. There are a number of other examples which you
can try out under the Help menu item along the top of the user interface, if you want to gain more
understanding of the software and how it can be used.
Figure 1: The metal forming “system”
1) Process Description and objective of the Simulation
This example shows an upsetting (or compression) of a cylinder. The simulation is conducted in a
2D axisymmetric mode, assuming the deformation and heat transfer are asymmetric about a
centerline. Axisymmetric modeling is computationally more efficient than doing a full 3D
simulation.
2) User Interface Layout
Simufact.forming has a user-friendly interface that combines pre-processing (i.e. setting up the
problem), simulation, and post-processing (looking at the results). Below is a brief introduction of
the user interface of Simufact.forming.
Figure 2 User Interface
Broadly, the interface has six parts:
1. Menu bar: all functionalities of Simufact.forming.
2. Toolbars: access for most common and frequently used functionalities in
Simufact.forming.
3. Process tree: the process tree of one or multiple processes and stage controls in a project.
4. Object catalog: all objects (geometries, materials etc.) in project.
5. Model view: one or multiple windows to view one or several processes for pre-processing.
6. Result view: one or multiple windows to view results of one or several processes for post-
processing.
3) How to set up the simulation
3.1 Creating the process
Create a new project by clicking the button New Project in standard toolbar, this will open the
window Application module. Since this is a cold upsetting process, select Cold forming.
Figure 3 Application module
By clicking on OK, the Process definition opens. Select the following:
Process type Upsetting
Simulation type 2D – axisymmetric
Solver type Finite Elements (FE)
Quantity of dies 0
Figure 4 Process properties
You can confirm your settings by clicking OK.
This upsetting process will use a finite element solver and the workpiece will be represented by
quad elements.
The preset process name usually includes the process type, the solver type and the chosen
simulation type: UpsettingFe2D. You are free to adjust the name by left clicking on the process
(in this case UpsettingFe2D) in the process tree to edit the process name.
Figure 5 Renaming the newly created process
3.2 Create geometries
The next step will be to create the geometries with Autoshape function. We will need two dies and
one workpiece. To create the dies and the workpiece right click in Object catalog, select Geometry
◊ Autoshape and create the bodies like below.
Figure 6 Creating bodies with Autoshape
Figure 7 Autoshape Die 1
Rename the first autoshape as UpperDie.
Figure 8 Autoshape Die 2
Rename the second autoshape as LowerDie.
Figure 9 Autoshape Workpiece
Rename the third autoshape as Workpiece.
3.3 Defining the press object
In this example a hydraulic press with constant velocity of 25 mm/s will be used. Please right click
in the Object catalog, select Press ◊ Manual. Enter the following data in the dialog box:
Press type Hydraulic Press
Velocity 25 mm/s
Figure 10 Defining the press object
Rename the press object as hydpress25mms.
3.4 Insert dies and attach the Geometries and the press
Open the menu by right clicking on in the Process tree and select Insert ◊ Dies ◊
from existing geometries.
Figure 11 Open the insert dialog
In the geometry list, select the UpperDie and the LowerDie, attach the UpperDie to the press
hydpress25mms and apply these changes by clicking OK.
Figure 12 Insert the Dies to process
Drag and drop the workpiece geometry on workpiece.
Please be aware that there are some restrictions when modeling 2D-axisymmetric models with
Simufact.forming:
x The forming direction has to be the z-direction.
This is essential for all press types except tabular motion.
x The main axis of the CAD geometries should be collinear with the z-axis of the global
coordinate system.
As you can see the bodies are not aligned. We want to align the LowerDie in the global origin. The
Workpiece and UpperDie will be aligned to the LowerDie by using the function Align bounding
box. A bounding box is the smallest cube around a body. It has three axes in spatial directions.
Each axis has a center, a minimum and a maximum. First of all we will align the LowerDie in the
global origin:
Figure 13 Call to translate LowerDie
Figure 14 Translate LowerDie
Afterwards we can align the Workpiece. We use the bounding box of the LowerDie as reference.
The following image shows the parameters. The center of the x- and y-axes of both bodies shall
be equivalent. But the minimum of the Workpiece’s z-axes shall be aligned to the maximum of
the LowerDie’s z-axes. That means the Workpiece’s bottom face is in contact with the LowerDie’s
top face.
Figure 15 Call to align bounding box
Figure 16 Align Workpiece to LowerDie
In a final step we want to align the UpperDie.
Figure 17 Align UpperDie to Workpiece
The UpperDie should be modelled at the bottom dead center, therefore we have to translate it
20mm in negative z-direction. At the same time we will translate the Workpiece 20mm in negative
z-direction.
Figure 18 Call to translate UpperDie
Figure 19 Translate UpperDie
Figure 20 Call to translate Workpiece
Figure 21 Translate Workpiece
Now the model should look like the image below:
Figure 22 Aligned model
3.5 Defining the material object
Material properties have to be assigned to the Workpiece. Therefore, right click in Object catalog
and select Material ◊ Library. In the material dialog box, right click on General Steel and select
15MnCr5_u and accept it with OK. Drag and drop the loaded material onto the Workpiece in the
Process tree.
3.6 Defining the friction object
In this example we will use friction coefficients created manually. Please right click on Object
catalog and select Friction ◊ Manual and enter the data as shown in the following figure and close
the friction library window. The name of the friction object is preset to Coulomb, change it to
Coulomb-0. Drag and drop Coulomb-0 onto UpperDie and LowerDie.
Specification mode Manual
Friction law Coulomb
Friction coefficient 0
Figure 23 Defining the friction object
3.7 Defining the heat object
The next step is to define the thermal properties of die and workpiece. In Object catalog, please
right click and select Heat ◊ Die ◊ Manual to set the die heat object. Confirm that the following
values are in the respective boxes and click OK.
Initial die temperature 20 Celsius
Heat transfer coefficient to environment 50 Watt / (m2 * K)
Heat transfer coefficient to workpiece Automatic
Emissivity for heat radiation to environment Automatic
Figure 24 Defining the heat object for die
A die heat object with name 20C should now appear in the Object catalog. Drag and drop it onto
the process UpsettingFe2D to assign the heat object to all dies belonging to the process. Next you
need to set the initial workpiece temperature and thermal properties. Please right click in the Object
catalog and chose Heat ◊ Workpiece ◊ Manual and make sure the following values are in the
respective boxes and click OK.
Workpiece Temperature – Initial or Reheated 20 Celsius
Heat transfer coefficient to environment 50 Watt / (m2 * K)
Emissivity for heat radiation to environment Automatic
Figure 25 Set thermal properties for workpiece
Please drag and drop the newly created heat object to the workpiece in the Process tree. The
Process tree should now look like the one shown in the following figure:
Figure 26 Process tree with workpiece and die temperature objects assigned
3.8 Defining axisymmetric simulation
Remember that all the imported and created geometries are in 3D. However, the simulation to be
performed will be an axisymmetric analysis. In the Process tree double-click on .
You will see a window about home position as shown below:
Figure 27 Home position warning
Click on No.
Make sure that the axisymmetric button is pressed, the axisymmetric plane center lies on
coordinates (0, 0) and angle is 90 degrees. Finally click to preview the 2D simulation cross
section.
Figure 28 Preview of asymmetrical cross section
Note: The cross section dialog must be closed by clicking on Close and then OK. If the cross
section window is open in the background, the position of the dies and the workpiece can’t be
changed.
3.9 Meshing the workpiece
To mesh the Workpiece, double click on Mesh in the Process tree. Change element size to 1 mm
and click on Create initial mesh. Close the window by clicking on OK and answer the following
questions with Yes.
3.10 Defining the forming control
Open the forming control by double clicking on in the Process tree. Select Stroke in the
Forming Control window. UpperDie is the moving die and its position is the bottom dead center,
therefore there is no need to define a stroke. Next click on Sub-stages and activate the following
settings:
Locate workpiece on stationary dies ON
Position dies attached to the press ON
Deformation of the workpiece ON
Release dies attached to the press ON
Release workpiece from the stationary dies ON
4) How to run the simulation
4.1 Check settings
To check if the simulation settings are correctly defined, click on the Check Data button . The
process must be correctly defined. If you get warning or error messages, then correct your
simulation settings accordingly.
4.2 Running the simulation
To run the simulation click on the Run button located in the control toolbar.
5) Post processing the simulation
In the process tree click on to select all components in the tree and click the
animation button or double-click on .
Figure 29 Animation of process
5.1 Stress Contours
To view stress contours, double-click on , in the result selection window click on Effective
stress.
Figure 30 Effective stress in result selection window
Figure 31 Animation of Effective stress
5.2 Strain Contours
To view stress contours, double-click on , in the result selection window click on Effective
plastic strain.
Figure 32 Effective plastic strain in result selection window
Figure 33 Animation of Effective plastic strain
5.3 Applied load vs stroke
To get the applied force vs extension data, click on the history plot button in the result bar.
To display just the curve that belongs to UpperDie, press on the upper right corner of the
history plot window. Check the box of UpperDie in the selection window.
Figure 34 Selection of the visible curves in history plot
Change the X-axis value to Stroke in mm and Y-axis to Z Force in N. Your history plot should
look similar to the following figure:
Figure 35 Force-stroke curve of UpperDie
To export the force-stroke data click on along the right border of Figure 35 and export the
data to a comma separated value (.csv) file and save that file.
Note: During compression, by convention the applied load would be negative and the change in
length would also be negative. However, in setting up the upsetting problem, simufact
automatically reports magnitudes of the applied load and stroke (change in length). That is why
the plot above has positive values for both load and stroke.
