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# Introduction to Sensors and Data Analysis
## ME 3263 Fall 2018
## ME 3263 Fall 2020

[ME 3263 Lab Report Rubric](./ME3263-grading_rubric.pdf)

Labs 0 and 1 have a 3-page limit and 2-figure limit. Labs 2-6 have a 5-page
limit and 4-figure limit. You can add additional pages and figures in an
Appendix. The Appendix will not be formally graded, but you can use it to refer
Appendix. The Appendix will not be graded, but you can use it to refer
to data, methods, or diagrams that are relevant.

The report is scored 0-100. Over 70 is passing. Late submissions receive 10
point penalty per day.

Part of your "writing assignments" grade is based upon the reports that you make
the final edits and improve the flow. The first author listed will get credit
for the writing assignment portions. Take turns as first author and co-author.
The group shares the pass/fail grade for the "lab report" grade.


# Repository for laboratory notebooks
*To access notebooks and interactive lab material, sign into github.uconn.edu,
then follow the link to the class server.*

# [ugmelab.uconn.edu](https://ugmelab.uconn.edu)
# ME3263 Introduction to Sensors and Data Analysis (Fall 2018)

## Lab #5 Mass Measurement Device with Cantilever beam

[Lab 5 github files](https://github.uconn.edu/rcc02007/ME3263-Lab_05.git)

# Mass measurement contest

In the mass measurement contest, you will use natural frequency shifts to
determine the mass of an object. There are three locations you can mount the
object as seen in Figure 1, where the object is mounted in position 2. The
experimental procedure only involves measuring natural frequency with the mass
mounted in different positions. You can create an *engineering model* as we will
do with experimental results from Ghatkesar *et al.* 2007
[\[1\]](./ghatkesar-et-al-2007_higher-mode-mass-sensors.pdf), as described in
section 2.

You can use the modal analysis in **Ansys**
[\[2\]](https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/main_page.html)
and apply a point mass to get predicted changes in natural frequencies. This
will create a table of values for your given cantilever for known masses for
*interpolation* as described in section 3.

**Rules of Contest**

1. The masses must not leave the lab

2. You cannot mount other known masses to the cantilever

3. You must report your uncertainty in your mass measurement to enter the
competition

4. You must report your serial number "TJM 01-TJM 12" to enter the competition

6. You may use the following tools and software: strain gage or accelerometer
(not both), calipers, Ansys, Labview, Python, Matlab, and Excel

**Winners of the contest**

There will be two sets of winners for the contest:

1. Lab group with the most accurate mass measurement calculated with
$A=|m_{reported}-m_{actual}|$

2. Lab section with the most precise mass measurement calculated with
$P=\sum_{i=1}^{N}(m_{reported}-m_{actual})^2$

Where $A$ is the accuracy, $P$ is the precision, $m_{reported}$ is the reported
mass from your experiment, and $m_{actual}$ is the actual mass of the object,
and $N$ is the total number of lab groups in a section. The group and section
with smallest A and P, respectively will win prizes. The prizes are as such

1. ** \$100 cash prize** put into your student accounts ($50/group member for
group of 2)

2. **Donuts/cookies** brought to your lab section

**Lab #5 report** should include details of the following

1. Your design of experiments

2. Your measured results

3. Your predicted results from Ansys

4. Your final calibration process for measuring a mass based upon natural
frequency changes


## Lab #4 Predicting Natural Frequencies with the Finite Element Method


### What is the Finite Element Method?

The Euler-Lagrange dynamic beam equation is an example of a partial differential
equation (PDE). These equations are common in many engineering applications e.g.
solid mechanics, electromagnetics, fluid mechanics, and quantum mechanics. The
finite element method solves PDEs. The FEM process involves two steps to create
matrices for a computer algorithm solution. First, the PDE is integrated from
the strong form to the weak form. Second, an approximation of the variable
"shapes" within each "element" is created to convert the integrals and
derivatives into matrices
[(1)](http://bcs.wiley.com/he-bcs/Books?action=index&bcsId=3625&itemId=0470035803).
For elements with nodes only at vertices, such as cubes (hexahedrons) or
pyramids (tetrahedrals), the "shape" function is linear for displacement.

[Lab 4 github files](https://github.uconn.edu/rcc02007/ME3263-Lab_04.git)

## Lab #3 Measuring Natural Frequencies

### What are natural frequencies

In free vibration (i.e., no external forcing), structural components
oscillate at specified frequencies or combinations of frequencies. Since
these vibrations are unforced, the associated frequencies are referred
to as natural frequencies; it's how the system vibrates if left to
behave on its own. In contrast, driven linear systems vibrate at the
driving frequency. An amplification of the response (called resonance)
occurs when the driving frequency coincides with one of the natural
frequencies. In short, the system is driven at a frequency at which it
likes to vibrate. Large amplitude oscillations are the result. So it is
important to know what the natural frequencies are *a priori* so you can
avoid driving the system into resonance.

[Lab 3 github files](https://github.uconn.edu/rcc02007/ME3263-Lab_03.git)

# Lab #2 - Static beam deflections with strain gage

## What is a Strain Gage?

A strain gage consists of a looped wire that is embedded in a thin backing. Two
copper coated tabs serve as solder points for the leads. See Figure 1a. The
strain gage is mounted to the structure, whose deformation is to be measured. As
the structure deforms, the wire stretches (increasing its net length ) and its
electrical resistance changes: $R=\rho L/A$, where $\rho$ is the material
resistivity, $L$ is the total length of the wire, and $A$ is the cross sectional
area of the wire. Note that as $L$ increases, the cross sectional area changes
as
well due to the Poisson contraction; the resistivity also changes.

![Figure 1: a) A typical strain gage. b) One common setup: the gage is
mounted to measure the x-direction strain on the top surface. It's
engaged in a quarter bridge configuration of the Wheatstone bridge
circuit.](./figure_01.png)

*Figure 1: a) A typical strain gage. b) One common setup: the gage is
mounted to measure the x-direction strain on the top surface. It's
engaged in a quarter bridge configuration of the Wheatstone bridge
circuit.*


# Lab #1 - Measurements of machining precision and accuracy

[Lab 1 github files](https://github.uconn.edu/rcc02007/ME3263_Lab-01.git)

**Outline and figures due in week 4 at beginning of lab**

**Final report due day before lab by 11:59pm**

**How can you measure something?**

All measurements have traceable standards. There are seven base units in SI -
meter (length), second (time), Mole (amount of substance), Ampere (electric
current), Kelvin (temperature), Candela (Luminous intensity), and kilogram
(mass) 1. Any measurement you make should have some method to check against a
reference. In this lab, we will use calipers that measure dimensions i.e.
meter 1E-3 (length). Calipers can always be verified to work with gage
blocks.

**Sources of measurement variations**

No measurement is exact. No surface is compeletely flat. Every measurement you
make has two types of uncertainties, systematic and random. Systematic
uncertainties come from faults in your assumptions or equipment.

# Lab #0 - Introduction to the Student t-test

**Outline and figures due Wed 9/5 by 5pm**

**Final report due Thu 9/13 by 5pm**

[Lab 0 interactive notebook in ipynb jupyter
notebook](https://mybinder.org/v2/git/https%3A%2F%2Fgithub.uconn.edu%2Frcc02007%2FME3263_Lab-0.git/f25072f2e708c231ea05040cab6aae2699a7be6f)

We use statistics to draw conclusions from limited data. No measurement is
exact. Every measurement you make has two types of uncertainties, *systematic*
and *random*. *Systematic* uncertainties come from faults in your assumptions or
Expand All @@ -197,3 +31,7 @@ model. Here are some examples for caliper measurements:
In theory, all uncertainies could be accounted for by factoring in all physics
in your readings. In reality, there is a diminishing return on investment
for this practice. So we use some statistical insights to draw conclusions.

# Labs 1-6 coming soon
check [HuskyCT](lms.uconn.edu), [Piazza](piazza.com/uconn/fall2020/me3263/home), and
[ME3263 repo](https://github.uconn.edu/rcc02007/me3263_labs) for updates!

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