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					Introduction To Upward Bound
Associate Professor

Dr. Larry D. Peel

Vishwajit Grudge
Graduate Student

Undergraduate Student

Dustin Grant

Department of Mechanical & Industrial Engineering Texas A & M University – Kingsville

Introduction of Everyone
Dr. Larry D. Peel

Vishwajit Grudge Dustin Grant

Upward Bound Students (5 weeks) Will start the same, will conduct additional work, and help grad students.

Website nd/Upward_Bound.htm

Project Objectives

Design, Analyze, Fabricate, and Test several types of rubber rope.

2. 3.


Demonstrate other Composite Fabrication Techniques. Design and build a better clipboard. Help graduate students with their research.

Uses of Composites

Composite Banjo

Composite Piccolo

Composite Shoes

Composite Guitar


Uses of Composites

Composite Baseball Bat from Miken Sports

Project Motivation


Why are you here? Why should we make something from Composites?
 

Web Search Discussion Web Search Discussion


Why make and test sandwich panels?


Reasons for Composites


Overview of Program
1. 2. 3. 4. 5. 6. 7. 8. 9. Basic Mechanics Basics in Strength of Materials Stress – Strain Curves Beam Theory 3 Point Bending Experimental Set-up of 3 Point Bending Composites Composite Material Cross - section Types of Fiber & Resins


Overview of Program
10. Uses of Composites 11. Laminated Composites 12. Rule of Mixture 13. Composite Fabrication
    Hand Lay-Up Vacuum Bagging for Hand Lay-Up Filament Winding Pultrusion

14. Finite Element Analysis of Composite Laminate using NE Nastran 15. References

Basic Mechanics
Mechanics: Study of forces acting on a rigid body a) Statics - branch of mechanics which considers the action of forces in producing rest or equilibrium of a body. b) Dynamics - branch of mechanics which treats of the motion of bodies (kinematics) and the action of forces in producing or changing their motion (kinetics).

Force: The capacity to do work or cause physical change. Pressure: Force applied uniformly over a surface, measured as force per unit of area.

Basic Strength of Materials
Stress: An applied force or system of forces that tends to strain or deform a body.

P Stress,   A Units - Pascal (Pa) or N
Strain: A deformation produced by stress. It’s the ratio of difference in length to the actual length. L  Initial Length A  Cross sectional Area Strain is always dimensionless. P  Applied Load  Strain,   11   Length Difference L


Stress - Strain Curves

Stress Strain Curve Engineering Stress Strain Curve for Steel for different metals


Stress - Strain Curves

Stress Strain Curve for Composites


Basic Strength of Materials
Young’s Modulus: The measure of the elastic force of any substance, expressed by the ratio of a stress on a given unit of the substance to the accompanying distortion, or strain. In other words, it’s a ratio of stress to strain.

 E 

Units - MPa
where σ is the stress, ε is the strain and E is a constant called the Young’s Modulus. It is also known as Material Stiffness.

Basic Strength of Materials
Hooke’s Law: We know that Hooke’s law is given by

  E
where σ is the stress, ε is the strain and E is a constant called the Young’s Modulus. Poisson’s Ratio:  is the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force.

 transverse 

 longitudin al

Beam Theory
Beam: A squared-off log or a large, oblong piece of timber, metal, or stone used especially as a horizontal support in construction.

Simply supported beam loaded at center

PL3 Maximum De flection, δ  P = Load applied on the 48EI Beam M L = Length of the Beam Stress,   y I You can also calculate deflection for a standard beam from this website: 16

3 Point Bending
Basic equation in bending stresses in beams

M   I y
We know,

PL M (moment)  4

h y 2

bh3 I  12

We can find the stress using the above equations.
Cross sectional view of beam

Experimental Set-up of 3 Point Bending

 

The 3 point bending test of the composite laminate will be conducted on the universal testing machine. The displacement can be measured by the moving head and the extensometer.


Composite Materials: They can be defined as a material with two (or more) distinct macroscopical phases. They consist of two or more materials combined in such a way that the individual materials are easily distinguishable. A common example of a composite is a concrete.


Composite Material Cross-section

In Borsic fiber-reinforced aluminum, the fibers are composed of a thick layer of boron deposited on a small – diameter tungsten filament.

Silver – Copper Alloy reinforced with Carbon Fibers.

Uses of Composites

Composite Bicycle Laminated Fiberglass Bow

Graphite Snowboard

Uses of Composites

Dodge Viper

Front grill of an Automobile

Different part of an airplane

Types of Fibers
Fiber Glass

Graphite Fiber

Kevlar Fiber

Kevlar/Carbon Hybrid


Types of Resins
Epoxy  Polyester  Vinyl Esters

Hardener Calculation:
Depending on the weight ratio of the resin & hardener, the amount hardener for the required amount of resin is calculated using:

Weight Ratio of Hardner Amount of Hardner  x Amount of Resin Weight Ratio of Resin
Calculations for the Amount of Resin required for the fibers will be shown in the lab.


Laminated Composites
Laminated Composites: Laminated composites can be thought of as sheets of continuous fiber composites laminated such that each layer has the fiber oriented in a given direction.


Rules Of Mixture
The Rule of Mixtures will accuratelypredict the relative amounts and the properties of the individual constituents. The general form is :

 c   f i . i  f1.1  f 2 . 2  ..... f n . n
where  c , is the density of the composite, 1 ,  2 ..,  n are the densities of the each consituents in the composite f1 , f 2 ... f n are the volume fraction of each consituent. A greater vo lume fraction of fibers increases the strength and stiffness of the composite.The Maximum volume fraction is about 80%, beyond which thefibers can no longer be completely surroundedby matrix.

Rules Of Mixture
As for thelaminated composites, the rule of mixtures always predicts the density of fiber - reinforcedcomposite:  c  Vm  m  V f  f where the subscriptsm and f refer to the matrix and fiber. Also, Vm  1  V f
If we consider the fiber to be isotropic, the Rule of Mixtures can be presented as: E  V E V E
1 m m f f

1 / E 2  Vm / Em  Vf / Ef 1 / G12  Vf / Gf  (1  Vf ) / Gm
where Gf and Gm are the fiber and matrix shear moduli.

Composite Fabrication

Types of Composite fabrication:
Wet Lay-up/Hand Lay-up  Filament Winding  Pultrusion  Resin Film Infusion (RFI)  Spray Lay-up  Resin Transfer Moulding (RTM)  Seemann Composites Resin Infusion Moulding Process (SCRIMP)  Vacuum Assisted Resin Transfer Moulding (VARTM)

Hand Lay-up

Resins are impregnated by hand into fibres which are in the form of woven, knitted, stitched or bonded fabrics. This is usually accomplished by rollers or brushes, with an increasing use of nip-roller type impregnators for forcing resin into the fabrics by means of rotating rollers and a bath of resin. Laminates are left to cure under standard atmospheric conditions.

Vacuum Bagging for Hand Lay-up

This is basically an extension of the wet lay-up process described above where pressure is applied to the laminate once laid-up in order to improve its consolidation. This is achieved by sealing a plastic film over the wet laid-up laminate and onto the tool. The air under the bag is extracted by a vacuum pump and thus up to one atmosphere of pressure can be applied to the laminate to consolidate it.

Filament Winding

This process is primarily used for hollow, generally circular or oval sectioned components, such as pipes and tanks. Fibre tows are passed through a resin bath before being wound onto a mandrel in a variety of orientations, controlled by the fibre feeding mechanism, and rate of rotation of the mandrel.


Fibres are pulled from a creel through a resin bath and then on through a heated die. The die completes the impregnation of the fibre, controls the resin content and cures the material into its final shape as it passes through the die. This cured profile is then automatically cut to length.

NE/Nastran v8.2

Steps: 1. Define the Material and its properties. 2. Draw the geometry of the model. 3. Mesh the model. 4. Apply the constraints and loads as required. 5. Analyze the model.

NE/Nastran v8.2
Example: Surface Geometry: Plate of 12” x 3” x 1”

In this example, Aluminum was taken to be the material for the plate. The Properties of Aluminum is predefined in the Nastran Software.


NE/Nastran v8.2
The plate is meshed and the the constraints and loads are applied as described below.

Constraint: Plate fixed on left side.
Load: Force of 60lbs is applied on the other edge.


NE/Nastran v8.2
Final Analysis done on the plate.


 Introduction to Composite Materials by Stephen W. Tsai and H. Thomas Hahn

 

Mechanics Of Composite Materials by Robert M. Jones
The Science and Engineering Of Materials By Donald R. Askeland And Pradeep P. Phule Peel, L.D., Jensen, D.W., Fabrication and Mechanics of Fiber-Reinforced Elastomers, Ph.D. dissertation at Brigham Young University, Dept. of Mechanical Engineering, Dec. 1998.

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