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Leaf Spring 1
Step
Leaf Spring (Material, Contact, geometric nonlinearity)
Summary
Summary 00 Nonlinear Static Analysis
- Unit: N, mm
- Geometric model: Leaf
Spring.x_t
Nonlinear Material configuration
- Stress - Strain Curve
definition
creation of Contact Condition
- General Contact (Rubbing
consideration)
Boundary and Load conditions
- Pinned, User defined
- Translational Disp.
Results verification
- Total displacement
- View of results in animation
Leaf Spring 2
Step
00 Analysis Summary
Creation of nonlinear contact
- Create nonlinear contact with manual contact function.
- Define contact between surfaces which are not in contact at the initial stage of the analysis, but will enter in contact during the analysis
- Make the model return to its initial position using Subcases
Tutorial purpose
Analysis Summary Target model Boundary Condition (Pinned, User defined) Load (Translational Disp.)
Pinned User defined (X,YAxis Boundaries )
Translational Disp. (After -ZAxis 8mm Translation, Return to its original position)
Leaf Spring 3
Step
00 Analysis Summary
Manual Contact
• Not in contact at the beginning of the Analysis. • After a vertical displacement in the bottom direction, the contact will be established
Contact establishment Contact establishment
•In this case, it is difficult to define automatically the contact when the spring isn’t in contact with the plate. •The user has to define manually the surfaces where the contact will be established. • Let’s see how a manual contact can be assigned in the Step 07 of this tutorial.
Leaf Spring 4
Step
Procedure
Model > Geometry> Import 01 Click on [ ] (New) Icon.
Click on [Geometry] - [Import].
Model: Select Leaf Spring.x_t.
Uncheck [Search Contact Faces].
Click on [Open].
※ Tutorial Models are at the same
location than midas NFX in the
folder Manuals / Tutorials /Files
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If the option [Search Contact Faces]
is checked, contacts will be
automatically defined to the faces in
contact.
The purpose of this tutorial is to
learn how to apply the contacts, so
we will uncheck this option.
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• Please verify the length unit of the model !
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Leaf Spring 5
Step
Procedure
Model > Geometry> Material 02
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Click on [Geometry] - [Material].
ID: “2” , Name: Enter “Spring”.
Select [Nonlinear] Tab.
Type of Material nonlinearity: Select
"Elasto Plastic".
Elastic Modulus: Enter “236339.3”.
Poisson's ratio: Enter“0.266”.
Check "Stress strain Data".
Click on the icon "Data Creation".
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By clicking on this Tab, a nonlinear
material is automatically defined.
Enter the Stress - Strain Curve.
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Explanation continues On the next page
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Leaf Spring 6
Step
Procedure
Model > Geometry> Material
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03 Name: Enter “Nonlinear Material”.
Strain: “(0)”, Stress: “(0)”
Strain: “(0.00112)”, Stress: “(264.70)”
Strain: “(0.00400)”, Stress: “(264.70)”
Strain: “(0.00837)”, Stress: “(276.14)”
Strain: “(0.01811)”, Stress: “(332.96)”
Strain: “(0.03170)”, Stress: “(383.16)”
Strain: “(0.04574)”, Stress: “(414.51)”
Strain: “(0.06505)”, Stress: “(439.14)”
Strain: “(0.08273)”, Stress: “(451.17)”
Strain: “(0.10447)”, Stress: “(458.31)”
Strain: “(0.12521)”, Stress: “(460.50)”
Click on [OK].
Stress - Strain Data: Select
“Nonlinear material”.
Click on [OK].
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For this tutorial, a plastic type stress-
strain curve is used.
The second point “0.00112” is the
last point of the elastic section for
this material and then it will be
defined as the yield stress.
Leaf Spring 7
Step
Procedure
Model > Geometry> Material 04 Click on [Geometry] - [Material].
ID: “3” , Name: Enter “Rigid”.
Elastic Modulus: Enter“2.5e5”.
Poisson's ratio: Enter“0.266”.
Click on [OK].
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Leaf Spring 8
Step
Procedure
Model > Geometry> Material (Material Assignment) 05 After selection of the model in the
working window, Right-click with the
mouse.
Select [Material] >[Spring].
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Leaf Spring 9
Step
Procedure
Model > Geometry> Material (Material Assignment) 06 After selection of the model in the
working window, Right-click with the
mouse
Select [Material] > [Rigid].
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Leaf Spring 10
Step
Procedure
Model > Geometry> Contact 07 Click on [Geometry] - [Contact].
Select [Manual Contact] Tab.
Select "Surface to Surface Contact".
Contact Type: Select "General
contact".
Master Faces: Select 1 Surface.
(Select the upper face of the plate.)
Slave Faces: Select 2 Surfaces.
(Select the both side surfaces below
the spring model.)
Click on the icon [ ] at the right
of the contact parameters.
ID: “2” , Name: Enter “Friction”.
Coefficient of Static Friction :
Select “0.3”.
Click on [OK].
Contact Parameters: Select Friction.
Click on [OK].
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General Contact: if general contact is used between two surfaces, when these two surfaces are in contact or not, the analysis is always possible, Master plane is displayed in red, whereas slave plane is displayed in blue.
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Leaf Spring 11
Step
Procedure
Model > Boundary > Support 08 Click on [Boundary] - [Support].
Click on [ ] (Top) Icon.
Name: Enter “Support” .
Target: Select 2 Surfaces (Reference
Picture)
Condition: Select [Pinned].
Click on [Apply].
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Leaf Spring 12
Step
Procedure
Model > Boundary > Support 09 Name: Enter “X,Y Fix”.
Method: Select [User defined].
Target: Select 1 Plane. (Reference
picture)
DOF: Select [Tx], [Ty].
Click on [OK].
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In order to restraint the movement
of the spring in Z direction only, we
have to fix its translation in X and Y
directions.
Leaf Spring 13
Step
Procedure
Model > Static load >Translational Disp. 10 Click on [Static Load] -
[Translational Disp.].
Click on [ ] (Isometric1).
Name: Enter “8mm Translation”.
Target: Select 1 Plane. (Reference
picture)
Components: Check [ZAxis],
Enter “-8”.
Click on [Apply].
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The spring model will be moving of
8mm in the –Z direction
After the movement down of the
spring, the spring will return to its
initial position (next page)
Leaf Spring 14
Step
Procedure
Model > Static load >Translational Disp. 11 Name: “Initial position” 입력.
Target: Select 1 Plane. (Reference
picture)
Components: Check [ZAxis],
Enter “0”.
Click on [OK].
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The spring returns to its initial
position. In analysis case, a subcase
will be created and Initial position
will be associated to it.
Leaf Spring 15
Step
Procedure
Model > Mesh > Auto Mesh 12 Click on [Mesh] - [Auto Mesh].
Target: Select All the Models (2
Models).
Select High Speed Tetra Mesher
Click on [OK].
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Leaf Spring 16
Step
Procedure
Analysis and Results > Analysis Case > Creation (Subcase Setting) 13 Click on [Analysis case] - [Create].
Name: Enter “Leaf Spring.
Analysis Type: Select [Nonlinear
static].
In the bottom corner of the window
[Subcase Setting], click on [Create]
and choose [Nonlinear Static
Analysis] to create a new Subcase.
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Subcase creation
Leaf Spring 17
Step
Procedure
Analysis and Results > Analysis Case > Creation (Subcase Setting) 14 <Change Subcase name>
Select Nonlinear Static Analysis
(Required), press the button F2 of
the keyboard and enter “8mm
Translation”
Select Subcase#1, press the button
F2 of the keyboard and enter
“Original position”.
<Analysis Condition Activation>
By clicking on the Icon [ ] at the
left of the Active part Sets, you can
move the Analysis conditions to the
newly created Subcase.
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Leaf Spring 18
Step
Procedure
Analysis and Results > Analysis Case > Creation (Subcase Setting) 15 In the Subcase “8mm Translation”,
Select the Load “Original position”
and Do a Drag-and-drop with the
mouse to drop it in the window All
Sets.
In the Subcase “Original position”,
Select the Load “8mm Translation”
and Do a Drag-and-drop with the
mouse to drop it in the window All
Sets.
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In the first Subcase, the spring is
moving down of 8mm.
In the second Subcase, the spring
returns to its initial position.
Leaf Spring 19
Step
Procedure
Analysis and Results > Analysis Case > Creation (Analysis Control) 16 Click on [ ] (Analysis Control)
Icon.
Select [Nonlinear] Tab.
Number of increments: Enter “20”.
Check [Displacement], Uncheck [Load],
Check [Work].
Check [Geometry Nonlinear].
Click on [OK].
Click on [OK].
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Total displacement (8mm) will be
calculated in 20 time steps.
To allow large deformations,
Geometry nonlinear option should
be checked.
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Leaf Spring 20
Step
Procedure
Analysis and results > Analysis > Perform 17 Click on [Analysis] - [Perform].
Click on [OK].
Save with another Name: Enter “Leaf
Spring”.
Click on [Save(S)].
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When the analysis perform is
launched, Midas NFX Solver will
automatically begin to work. You can
stop the analysis by pressing the
button Stop Execution!
Leaf Spring 21
Step
Procedure
Analysis and Results working Tree> Leaf Spring > Nonlinear Static Analysis > Total displacement (8mm Translation) 18
Select Real Scale.
In the Analysis and results working
Tree, double-click on “8mm
Translation” INCR=21, Total
displacement
Click on [ ] (Multi - Step
animation Recording).
Click on [ ] (Play) Icon
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This is the analysis result of the 8mm
down translation.
the animation can be displayed from
step 1 to 21.
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Leaf Spring 22
Step
Procedure
Analysis and Results working Tree> Leaf Spring > Nonlinear Static Analysis > Total displacement (Original displacement) 19
Select Real Scale.
In the Analysis and results working
Tree, double-click on “Original
position” INCR=20, Total
displacement
Click on [ ] (Multi - Step
animation Recording).
Click on [ ] (Play) Icon
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After the 8mm down translation, the
spring returns to its original position.
the animation can be displayed from
step 1 to 20.
※ As the model is subject to large deformations, the material is in plastic deformation state and can’t return to its original state
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