Plate with HOLE stress analysis

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Laboratory Training for ANSYS

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Analysis of stressed plate with/without hole in ANSYS:

Using General User Interface (GUI) and command codes

(May 27, 2011)

In this training, you will learn how to use the basic GUI and command codes of

ANSYS 11.0 to model a structural problem. The procedure on how to model a

certain structural problem will be presented (i.e. preprocessor solution

general postproc).

The purpose of this analysis is to model a rectangular plate with/without a

hole. The plate is made of isotropic material having elastic modulus of 200000

MPa and Poisson's Ratio of 0.3. The length and width of the plate are 400 mm and

200 mm respectively. The diameter of the hole in the middle of the plate will be

changed or removed to compare the changes of in the magnitude of stresses. The

boundary condition of the left end is fixed and the right end is displaced by 1 mm.


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ANSYS 11.0 Environment

Preprocessing: Defining the Problem

1. Give the current analysis a TitleUtility Menu > File > Change Title

Enter: Biomech Laboratory TrainingAlternatively, you can use the command code instead of GUI

/title, Biomech Laboratory Training

2. Create Geometrya. Create the main rectangular shape

Create the main rectangular area using GUI

Preprocessor > Modeling > Create > Areas > Rectangle > By 2Corners

Utility Menu

Main Menu

Status Bar/Input Window

Work Plane (WP)

View Icons

Command Code Input Line


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Fill in the window as shown above. This will create a rectangle wherethe bottom left corner has the coordinates (0, 0, 0) and the top right

corner has the coordinates (400, 200, 0).

The command line code for the above command isBLC4,0,0,400,200

b. Create the circlePreprocessor > Modeling > Create > Areas > Circle > Solid Circle


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Fill in the window as shown above. This will create a circle where thecenter has the coordinates (200, 100, 0); the center of the rectangle,

and the radius of the circle is 50 mm.

Alternatively, the command line code for the above command isCYL4,200,100,50

c. Subtraction Now we want to subtract the circle from the rectangle. Prior to this

operation, your image should show the following:

Modeling > Operate > Booleans > Subtract > Areas

At this point a 'Subtract Areas' window will pop up and the ANSYSInput window will display the following message: [ASBA] Pick or enter

base areas from which to subtract (as shown below) Therefore, select the base area (the rectangle) by clicking on it.

NOTE: The selected area will turn pink once it is selected.

Ensure that the entire rectangular area is selected (otherwise click'Next') and then click 'OK'.

Click 'OK' on the 'Subtract Areas' window.


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Now you will be prompted to select the areas to be subtracted, selectthe circle by clicking on it and then click 'OK'.

You should now have the following model:

Alternatively, the command line code for the above step isASBA,1,2


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3. Define the Type of ElementIt is now necessary to define the type of element to use for our problem:

Preprocessor Menu > Element Type > Add/Edit/Delete

Add the following type of element: Solid (under the Structural heading) andthe 8node 82 element, as shown in the figure below.

For this example, we need a plane stress element with thickness, therefore

Click on the 'Options...' button. Click and hold the K3 button, and select'Plane strs w/thk', as shown below.

Alternatively, the command line code for the above step is

ET,1,PLANE82

followed byKEYOPT,1,3,3

4. Define Geometric PropertiesPreprocessor menu > Real Constants > Add/Edit/Delete

Enter a thickness of 20 as shown in the figure below. This defines a platethickness of 20mm.


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Alternatively, the command line code for the above step isR,1,20

5. Element Material PropertiesPreprocessor > Material Props > Material models > Structural > Linear > Elastic

> Isotropic

We are going to give the properties of Steel. Enter the following whenprompted:

EX 200000 (elastic modulus)

PRXY 0.3 (Poissons Ratio)

Alternatively, the command line code for the above step is

MP,EX,1,200000

followed byMP,PRXY,1,0.3

Mesh SizePreprocessor > Meshing > Size Cntrls > Manual Size > Areas > All Areas

Alternatively, the command line code for the above step isAESIZE,ALL,5,

MeshNow the frame can be meshed.


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In the 'Preprocessor' menu select Meshing > Mesh > Areas > Free and selectthe area when prompted

Alternatively, the command line code for the above step isAMESH,ALL

You should now have the following:

Save Your Job

Utility Menu > File > Save as...

Solution: Assigning Loads and Solving

You have now defined your model. It is now time to apply the load(s) and constraint(s) and

solve the resulting system of equations.

1. Define Analysis Type Ensure that a Static Analysis will be performed (Solution > Analysis Type >

New Analysis).

Alternatively, the command line code for the above step isANTYPE,0

2. Apply Constraints As indicated previously, the left end of the plate should be fixed.


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Solution > Define Loads > Apply > Structural > Displacement > On Lines

Select the left end of the plate and click on 'Apply' in the 'Apply U,ROT onLines' window.

Fill in the window as shown below.

This location is fixed which means that all DOF's are constrained. Therefore,select 'All DOF' by clicking on it and enter '0' in the Value field as shown

above.

NOTE: You will see some blue triangles in the graphics window indicating the

displacement constraints.

Alternatively, the command line code for the above step isDL,4,,ALL,0

3. Apply LoadsSolution > Define Loads > Apply > Structural > Displacement > On Lines

When the window appears, select the line along the right hand edge of theplate and click 'OK'


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Alternatively, the command line code for the above step isDL,4,,UX,1

4. Solving the SystemSolution > Solve > Current LS

Alternatively, the command line code for the above step isSOLVE

Postprocessing: Viewing the Results

1. DeformationGeneral Postproc > Plot Results > Deformed Shape > Def + undeformd

(to view both the deformed and the undeformed object)

Observe the locations of deflection.


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2. DeflectionGeneral Postproc > Plot Results > Nodal Solution... Then select DOF solution,

USUM in the window.

3. StressesGeneral Postproc > Plot Results > Nodal Solution... select Stress, von Mises inthe window. OR General Postproc > List Results. Select Stress, Principals SPRIN


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Other Tasks:

1. Analyze a plate without hole and obtain the stress at the same region.2. Reduce the hole radius (i.e. 50 mm 10 mm 5 mm). Obtain the stress

at the same region and compare it with the plate without hole.

Summary of Command Line Codes

! The exclamation mark is used to cancel a command in ANSYS

/title, Biomech Laboratory Training

/PREP7 !Enter preprocessor

BLC4,0,0,400,200 !Create rectangle, bottom left corner coordinate, width, height

CYL4,200,100,50!Create circle, center coordinate, radius

ASBA,1,2 !Substract area 2 from area 1

ET,1,PLANE82 !Use element type (plane 42)

KEYOPT,1,3,3 !This is the changed option to give the plate a thickness

R,1,20 !Real Constant, Material 1, Plate Thickness

MP,EX,1,200000 !Material Properties, Young's Modulus, Material 1, 200000

MP,PRXY,1,0.3 !Material Properties, Major Poisson's Ratio, Material 1,

AESIZE,ALL,5 !Element sizes, all of the lines, 5 mm

AMESH,ALL !Mesh the lines

FINISH !Exit preprocessor

/SOLU !Enter solution

ANTYPE,0 !The type of analysis (static)

DL,4, ,ALL,0 !Apply a displacement to Line 4 to all DOF

DL,2, ,UX,1 !Apply a displacement to Line 2 (5mm)

SOLVE !Solve the problem

FINISH !Exit solution

Change radius Put ! if

no hole

Plate with HOLE stress analysis

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