Composites Fiber Ansys

8/13/2019 Composites Fiber Ansys

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Modeling of Composite Tubes

Using ANSYS

JEFF KAPKE

ME 450 Introduction to CAE

May 3, 2000

Submitted to: Professor H.U. Akay


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Uses for Composite Materials

Aircraft

Prosthetic Limbs

Auto body

Auto Frame

Bridge Reinforcement

Shafts and Rods

Body Armour


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Advantages of Composites

Density of aluminum alloy approximately 2800

kg/m3

Density of carbon/epoxy approximately 1580kg/m3

Tensile strength of aluminum alloy 7075-T6 is

570 MPa Tensile strength of carbon/epoxy 1830 MPa


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Isotropic vs. Orthotropic

E

E

EE

E

E

E = E =E=E =E =E

E1

E2

Ey

Ex

Ex EyE1 E2


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Fabrication


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Layers of a Composite Tube

Each color represents a different fiber orientationand change in material properties relative to the

Global Axis.

X


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Modeled Tube in ANSYS


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Element Coordinate SystemShell 91 From ANSYS Element Library

Theta

Y

Z

XI

L K

J

Ex

Ex

Element Type is SHELL91


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ANSYS Coordinate System for

Shell Element

x

zy

z

x

y

zx

y


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ANSYS Element Coordinate

System


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ANSYS Model SetupConstrained with Point Load


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ANSYS Model SetupConstrained with Uniform Load


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Real Test on Composite Tube


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Filament Wound Tube


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Deformed and Un-deformedPoint Load with 90oFiber Orientation


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Von Mises PlotPoint Load 0o Orientation


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Von Mises Plot

Point Load/90oOrientation


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Von Mises Graph of 90o/Hoop

Orientation


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Von Mises Graph of 0o/Longitudinal

Orientation


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Von Mises Plots of Uniform Loading with

Different Orientations

0oOrientation 90oOrientation

[0o

,90o

,

45o

]s


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Displacement of Point Loaded 90o/Hoop Orientation(Maximum Displacement 4.934mm)


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Displacement Related to

Orientation

Uniformly loaded hoop hasgreatest displacement.

Combination of layers

decreases displacement.

Displacement related tostiffness.

0

1

2

3

4

5

6

Lo

ng

Pnt

Ho

op

Pnt

Long

Hoop

[0,9

0,4

5]s


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Results of Changing Orientation

Hoop or 90oorientation is strong under

transverse loading.

Longitudinal or 0oorientation is stiffer inbending.

Combination of orientations increases

stiffness and strength.


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Difficulties with ANSYS

Creating model is not straight forward andsimple.

Meshtool does not recognize that all element

axis should coincide within each layer.

ANSYS is too powerful for simple problems.


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Advantages of ANSYS

Changing material properties or layer

orientation is simple.

Many different orientations can be analyzed ina short amount of time.

ANSYS can predict results before fabricating

composite sample. Complex geometries can be modeled and

evaluated easily.


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New Ideas

Analyze tube in torsion.

Apply moment instead of load.

Test as a pressure vessel.

Model unique geometries and

compare results. Model a beam or flat plate and

compare with actual results.

Composites Fiber Ansys

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