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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