WORKSHOP 16 STIFFENED PLATE - FSB Online · Submit the model to MSC.Nastran for a linear static...

WS16-1NAS120, Workshop 16, May 2006Copyright© 2005 MSC.Software Corporation

WORKSHOP 16STIFFENED PLATE


Workshop ObjectivesPractice modeling a stiffened plate.


Problem DescriptionA thin plate is reinforced with two types of stiffeners.The outer edges of the plate are reinforced with I-beam stiffeners.The interior of the plate is reinforced with three hat stiffeners.The structure is simply supported at two edges.A uniform pressure of 5 psi is applied to the surface of the plate.

20.0

5.0 TYP

20.0


Problem Description (cont.)The plate and stiffeners are constructed from aluminum alloy 7075-T73 with the following properties:

E = 10 x 106 psi

ν = 0.3

The plate is 0.100 in thick.


Problem Description (cont.)The I-beam stiffener has the following cross section:

2.0

1.0

0.1 TYP


Problem Description (cont.)The rolled hat stiffener has the following cross section:

B B

A

A

2.0

1.0

0.898

0.785

Cross-Sectional Area

0.504 in2

IAA 0.143 in4

IBB 0.174 in4

J 0.0016 in4


Suggested Exercise Steps1. Create surface geometric representing the plate.2. Mesh the geometry to create plate (CQUAD4) and bar (CBAR)

elements.3. Define material (MAT1) and element properties (PSHELL and

PBAR).4. Verify the Y-element axis and offset vectors for the bar elements.5. Define simply-supported boundary constraints (SPC1) and apply a

uniform pressure load to the plate (PLOAD4).6. Submit the model to MSC.Nastran for a linear static analysis.7. Post process the results.


CREATE NEW DATABASE

Create a new database called stiffened_plate.db.

a. File / New.b. Enter stiffened_plate as

the file name.c. Click OK.d. Choose Default Tolerance.e. Select MSC.Nastran as the

Analysis Code.f. Select Structural as the

Analysis Type. g. Click OK.

a

b c

d

e

f

g


Step 1. Geometry: Create / Surface / XYZ

Create the surface.a. Geometry: Create /

Surface / XYZ.b. Enter <20 20 0> for the

Vector Coordinate List.c. Click Apply.

a

b

c


Step 1. Geometry: Create / Curve / XYZ

Turn on the Show Parametric Direction feature.

a. Display / Geometry...b. Check the Show

Parametric Directionbox.

c. Click Apply.d. Click Cancel.

b

c d

a


Step 1. Geometry: Edit / Surface / Break

Break the surface in the u-direction.

a. Geometry: Edit / Surface / Break.

b. Change the Option to Parametric.

c. Choose Constant u Direction as the Break Direction.

d. Enter 0.5 as the Break Curve value.

e. Screen pick the surface created earlier.

f. Answer Yes when the question “Do you wish to delete the original surfaces?” appears.

a

b

c

d

e

e


Step 1. Geometry: Edit / Surface / Break

Break the surfaces again in the u-direction.

a. Screen pick the bottom surface.

b. Answer Yes when the question “Do you wish to delete the original surfaces?” appears.

c. Screen pick the top surface.

d. Answer Yes when the question “Do you wish to delete the original surfaces?” appears.

e. Click on the Show labelsicon.

e

c

a


Step 2. Finite Elements: Create / Mesh / Surface

Generate plate elements using IsoMesh.

a. Elements: Create / Mesh / Surface.

b. Select Quad as the Element Shape.

c. Select IsoMesh as the Mesher.

d. Select Quad4 Element Topology.

e. Select all the surfaces.

f. Enter 2.0 as the Global Edge Length.

g. Click Apply.h. Click on Hide labels icon.

a

h

bc

g

d

e

f


Step 2. Finite Elements: Create / Mesh / Curve

Generate bar elements along the longitudinal edges of the surfaces.

a. Elements: Create / Mesh / Curve.

b. Choose Bar2 as the element Topology.

c. Select 5 horizontal surface edges.

d. Click Apply.

a

b

c

d


Step 2. Finite Element: Equivalence / All / Tolerance Cube

Equivalence the model nodes to connect elements along surface edges.

a. Elements: Equivalence / All / Tolerance Cube.

b. Click Apply.

a

b


Step 3. Material: Create / Isotropic / Manual Input

Define a material for the model. a. Material: Create / Isotropic /

Manual Input. b. Type in alum for the Material

Name.c. Click on the Input Properties

button to bring up the Input Options window.

d. Enter 10E6 for the Elastic Modulus and 0.3 for Poisson Ratio.

e. Enter 0.101 for the Density.f. Click OK to return to the main

material menu. g. Click Apply.

d

e

f

a

b

g

c


Step 3. Element Properties: Create / 2D / Shell

Create element properties for the plate elements.

a. Properties: Create / 2D / Shell.

b. Enter plate as the Property Set Name.

c. Click on the Input Propertiesbutton.

d. Click on the Matl Prop Nameicon.

e. Click on the alum in the Select Existing Material window.

f. Enter 0.1 as the thickness. g. Click OK.h. Select all surfaces for the

Application Region.i. Click Add. j. Click Apply.

d

f

e

g

a

b

c

hi

j


Step 3. Element Properties: Create / 1D / Beam

Create element properties for the hat stiffeners.

a. Properties: Create / 1D / Beam.

b. Enter hat_stiffener as the Property Set Name.

c. Click on the Input Propertiesbutton.

d. Click on the Matl Prop Nameicon.

e. Click on alum in the Select Existing Material window.

f. Enter <0 0 1> for the Bar Orientation.

g. Enter <0 0 .948> for the offset at Node 1 and Node 2.

df

e

g

a

b

c


a


a. Scroll down the properties window to enter the following section properties:

Area = 0.504Inertia 1,1 = 0.174Inertia 2,2 = 0.143Torsion Constant = 0.0016

b. Scroll further down to enter stress recovery point coordinates as shown to the right.

c. Click OK.

b

c



a. Click on Select Members, then click on the beam element filter.

b. For the application region select three rows of bar elements.

c. Click Add. d. Click Apply.

ac

d

a



Next, create element properties for the I-beam stiffeners.

a. Properties: Create / 1D / Beam.

b. Enter i_stiffener as the Property Set Name.

c. Click on the Input Properties button.

d. Click on the Matl Prop Name icon.

e. Click on alum in Select Existing Material window.

f. Enter <0 0 1> for Bar Orientation.

g. Enter <0 0 1.05> for the Offset at both nodes.

h. Click on Beam Library icon.

df

g

e

h

a

b

c



a. Enter i_section for New Section Name.

b. Select the I-Beam shape option.

c. Enter dimensions for the I-Beam as shown.

d. Click on Calculate/Displayto view the cross section.

e. Click OK.f. Click OK again.g. Select the curve or edge

filter.h. For the application region,

select the top and bottom edges of the plate.

i. Click Add.j. Click Apply.

a

b

c

d

e

g

hi

j


Step 3. Viewing / Angles …

Change the viewing angle.a. Viewing/ Angles... b. Select Model Absolute.c. Input 23.0 34.0 0.0 as

the Angles.d. Click Apply.e. Click Cancel

b

c

d e

a


Step 4. Display / Load/BC/Elem Props…

Change the display settings to show beam offset.

a. Display / Load/BC/Elem Props... b. Change Beam Display from 1D line

to 1D line + offsets c. Click Apply.d. Change Beam Display to 2D Mid-

Span + Offsetse. Click Apply.f. Change Beam Display to 3D Full-

Span + Offsets.g. Change Beam Display to 3D Full-

Span + Offsets + Equivalent I.h. Click Apply.i. Click Cancel.

b

c

d

f

i

g

a



1D + Offsets

2D + Offsets 3D + Offsets

1D

3D + Offsets + Equivalent I


Step 4. Element Properties: Show

Verify the orientation of the hat sections by plotting the element y axis.

a. Properties: Showb. Select Bar Orientation

in the properties window.

c. Select the default_group.

d. Click Apply.

a

b

c

d



Change the display of loads, boundary conditions, and element properties from geometry to finite elements.

a. Display / Load/BC/Elem Props...

b. Check the Show on FEM only box.

c. Click Apply.d. Click Cancel.e. Repeat steps from previous

page to plot the element y axis for the stiffeners.

b

c d

a


Step 5. Loads/BCs: Create / Displacement / Nodal

Create the boundary condition for the model.

a. Loads/BCs: Create / Displacement / Nodal.

b. Enter Simple_Support as the New Set Name.

c. Click on the Input Databutton.

d. Enter <0 0 0> for the Translations.

e. Click OK. f. Click on Select Application

Region. g. Select Geometry as the

geometry filter. h. Set the picking filter to Curve

or Edge.i. Select the left and right edges

of the plate.j. Click Add.k. Click OK. l. Click Apply.

d

e

g

h

i

j

k

a

b

cf

l


Step 5. Loads/BCs: Create / Displacement / Nodal

Stiffened plate with two edges constrained.


Step 5. Loads/BCs: Create / Pressure / Element Uniform

Apply pressure to the model.a. Loads/BCs: Create / Pressure

/ Element Uniform. b. Enter pressure as the New

Set Name.c. Select 2D as the Target

Element Type. d. Click on the Input Data

button.e. Enter 5 in the Top Surf

Pressure field. f. Click OK. g. Click on Select Application

Region button. h. Select Geometry as the

Geometry Filter. i. Set the picking filter to

Surface.j. Select all the surfaces for the

Application Region. k. Click Add, and OK. l. Click Apply.

e

f

h

i

j

k

a

b

c

dg

l


Step 5. Loads/BCs: Create / Pressure / Element Uniform

Stiffened plate model with applied pressure.


Step 6. Analysis: Analyze / Entire Model / Full Run

Submit the model for analysis. a. Analysis: Analyze / Entire

Model / Full Run. b. Click on the Solution Type. c. Select LINEAR STATIC as

the Solution Type. d. Click OK. e. Click Apply.

a

b

c

de


Step 7. Analysis: Attach XDB / Result Entities / Local

After the job is completed, attach the XDB result file.

a. Access Results / Attach XDB / Result Entities.

b. Click on Select Result File. c. Select the file called

stiffened_plate.xdb. d. Click OK. e. Click Apply.

a

c

d

e

b


Step 7. Results: Create / Quick Plot

Plot plate stress and deformation results.

a. Results: Create / Quick Plot.

b. Select the Default result case.

c. Select Stress Tensor for the Fringe Result.

d. Select Displacement, Translational for the Deformation Result.

e. Click Apply.

a

b

c

d

e


Step 7. Results: Create / Quick Plot

Plot bar stress results. a. Select Bar Stresses,

Maximum Combinedfor the Fringe Result.

b. Click Apply. c. Plot the remaining bar

stress components one at at time.

a

b

c

WORKSHOP 16 STIFFENED PLATE - FSB Online · Submit the model to MSC.Nastran for a linear static...

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Transcript of WORKSHOP 16 STIFFENED PLATE - FSB Online · Submit the model to MSC.Nastran for a linear static...