Stress, Strain & Composite Material
Michael
1Reading
High School, Cincinnati, OH;
1
Day ,
2Woodward
Sarah
Teacher Guide, Day 2:
ACS Connections:
A: Students develop skills for solving equations, gather and
analyze information,
C: Students identify the skills needed for a career in
research. Understanding that sometimes answers are not
known.
S: Students are able to communicate findings to others.
They shall be able to see other uses for the technology
involved.
Materials
Various PVC Pipe
Various Copper Pipe
Clamps
Weights
Conductive Wire
Volt Meters
Glue
Rulers
Engage: RET project and all the cool data I collected.
Explore: Equations I used and manipulated.
Explain: Re-teach how to solve for certain variables given
equations.
Elaborate: Students make their own self-sensing composite
material.
We have incorporated nanotubes into
polymer composites to determine
structural failures before they become
critical by assessing stress and
resistance over time in 4-point
bending. We then compare the
change in resistivity in coordination
with applied stress and strain and
evaluated their usefulness as a
predictor of failure in composite
materials.
Inertia (I) as a function of width (w) and
height (h)
M
  *y
I
Stress (σ) as a function of Moment (M), Inertia (I),
and half the height (y)
M

*y
I *E
Strain (ε) as a function of Moment (M), Inertia (I),
Elasticity (E), and half the height (y)
M* h 3
w
**yy
I *I12
E
I
Explain: Show samples from RET project with CNT threads.
2
Stress = 20 MPa
Stress = 15 MPa
Stress = 10 MPa
1
0.5
0
Test #2
Test #3
Objectives:
1. Students will be able to identify the 4 different types of
bones (long, short, flat and irregular) and describe common
stresses normally sustained.
2. Students will be able to compare the functionality of
normal and diseased bone
C/S:
Many students are interested in careers in
medicine or research. The ability to take a common
problem and define a need and then solve that need is
the basis of engineering solutions to the benefit of
society.
-0.5
-1
200
400
600
800
CNT Diameter
Explore: Is the data linear? What else effects the bending?
Acknowledgements
Elaborate: Find the function. We will use calculators and excel
spreadsheets to find a best fit model.
Increase the weight and what
happens to the displacement?
Observe the difference in the resistance
with increased weight!
WHY?
Day 1-2 Warm-up ? What
holds us up? Describe how
our support system works. (5
min)
Complete warm-up
Teacher
We would like to thank The University of
Cincinnati and the National Science foundation
For this opportunity as well as the support staff:
A. Kukreti, PhD
A. Burrows, PhD
J. Abot, PhD
Yi Song, PhD Candidate
Sandeep Medikonda, PhD Student
Remove samples from
vinegar and rinse with
water.
Warm-up?: What are
stress and strain?
Compete for a prize with
teams
Fill in worksheet while
going over chapter data
Teacher
Student:
Warm-up?; What chemicals
are an important part of bone,
(5 min)
Begin Lab
Record initial data
(mass, volume calc
density} on bone,
Put bone in vinegar
Assign research question:
Research Osteoporosis:
describe the process that
occurs in the development of
osteoporosis. Compare the
structure of normal bone to the
structure of osteoporotic bone.
Describe how normal bone
functions.
Predict how osteoporotic
changes will affect the function
of bone under stress.
Student:
Introduce the concept of
stress and strain and
demonstrate how it is
tested
Day 3:
Time (s)
Refer to individual Lesson Plans
Explain: More than one variable can affect the outcome.
Teacher
1000
References
Using weight to bend the wood.
balance scale
method for measuring volume
light microscopes/bone slides
Day 4:
Use microscope to view
slides of bone, draw
diagram of what is seen
at 4x and 10x
place in hood to dry
Design of a method to test
how much stress, sketch
design in lab notebook,
begin to build.
Day 5-6:
-1.5
Sample: Yes, we
broke it!!!
Engage: How to bend materials!
Worksheet for PPT (guided notes)
Samples of bone, shank, pelvis, vertebrae
Lab directions
Student:
Intro to the human skeleton
PPT with coordinating
worksheet
Test #4
Evaluate: Finish lab report and make a poster with findings.
Present, as a group, the findings to the class.
functions, predict
A: Students must understand how unhealthy behaviors
can affect them, poor nutrition can eventually lead to
osteoporosis. Understanding is the beginning for long
term prevention.
Open section with Bulldog
Feud, to assess prior
knowledge.
1.5
Elaborate: Students do their own experiment.
Teacher Guide, Day 1:
ACS Connections:
Goals: Students will understand the function of the skeletal
system, stresses incurred by different bones in the human
body and be able to describe the differences in normal and
diseased bone and how it reacts to its environment.
(Sample II, Thread B)
0
Evaluate: Students will plot data, find
linearity, and find slope.
Objectives:
Day 1-2:
Resistance History
Explore: Why did it fail? Could a sensor have helped detect
when it was going to happen?
How much
was the displacement?
Sarah Woodward, Anatomy Lesson:
PPT for Skeletal system
Marieb text
Lab notebooks
Materials Lab Equipment
Teacher Guide, Day 3:
of Aerospace Eng. & Eng. Mechanics
Materials
Examples of equations that were used in the RET project:
Engage: Destroy a bridge!
Using weight
to bend the
pipe!
3Department
Evaluate: Lab reports will be started, along with solving
scientific equations for a specific variable.
w * h3
I
12
3
Abot
Abstract
Change Resistance (ohms)
 Solve for variables given a formula
 Students will take data and infer if it will be
linear or another function.
 Students will be able to graph the data and
make a scatter plot. Then find the function.
Jandro
High School, Cincinnati, OH;
Michael Day, Pre-Calculus Lesson:
Objectives:
2
Woodward ,
Teacher
Student
Warm-up?; What do you
think will happen to the
decalcified bone under
stress, how will that
compare to normal bone.
Record dry data,
draw a diagram of test,
test stress/strain
Remind students of
research presentations
Enter data into Excel
and graph results
Complete conclusion
Day 7:Assessment
Students will present co teach exercise and be graded on
rubric for comprehension.
Students will be given a series of free body diagrams of
different types of bones and be asked to label the forces
that act on the bone.
Predict the location of fractures when different types of
bones are put under stress, describe the difference in the
location of fractures and the force necessary in diseased
bone.