OREGON STATE UNIVERSITY

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15 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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1

OREGON STATE UNIVERS
ITY

ME 453


STRUCTURE AND MECHAN
ICS LABORATORY

Lab 1

Questions


Winter 20
1
2


Logistics
: Responses to the following questions are due at the beginning of your
next
lab session
.
You may share among your lab group any data and analysis results that were generated during the
lab exercise, but work independently in developing responses to the questions.
I am looking for
specific, focused answers, not vague, lengthy
ones
.


Question 1
:
What is your name, and who were your lab group members? Describe briefly the role
that you played in setting up and carrying out the lab project.


Question 2
: The fundamental experimental step was conversion of strain gage readings into

strain
tensor components expressed in a specific coordinate system. Refer to the lab 1 introduction
handout. How would Equation 2 change if the rosette gauge were bonded upside down from the
configuration shown?


Question 3
: Illustrate and describe
analysis of beam shear stress and strain, paying particular
attention to the infamous “Q” term.

Describe for analysis
locations at the neutral axis

and offset
vertically toward the top of the beam.


Question 4
: Create an organized and labeled spreadsheet t
hat shows your strain tensor component
data. Bring this in electronic form to lab with your hardcopy question responses. Include the
calculation of results used for Question 5.


Question
5
: Develop two plots of your results. Follow the data plotting guide
lines in the lab handout.
Be sure to include theoretical analys
e
s with bounds.


Plot 1: Strain tensor components versus beam end load.


Plot
2
: Maximum shear strain magnitude versus beam end load.


Plot
3
: Maximum and minimum princi
pal strain versus beam
end load.


Question
6
: Identify your most representative set of data (closest to the mean value) at the highest
beam end load level. Plot Mohr’s circle for this strain state, clearly indicating the orientation of the
measurement coordinate system.
Also plo
t Mohr’s circle for the ideal beam theoretical analysis.


Question
7
: For the same data used in Question 5, identify the extent to which the
experimental
data varies from a perfect “pure shear” state, and show me an analysis that explains the discrepancy
in terms of beam loading or gauge positioning artifact.


Question
8
: Create
a stress/strain plot

for the tension data collected during your lab session, and
show the calculation of modulus.


Question
9
: How dependent is this experiment on the value of elastic modulus? Do not perform a
full sensitivity analysis, just make a point, and then support it by referencing a specific result.


Question 10:

Draw a conclusion as to weather this experiment provides

validation of the simple
beam shear stress equation. Reference specific results. Make recommendations of ways to improve
the experiment, citing specific factors that created uncertainty in our experiment.