PASCO AP-8214 User manual

800-772-8700 www.pasco.com
®Instruction Manual
012-09424B
Stress/Strain Apparatus
AP-8214
Included Equipment Part Number
A. Stress/Strain Apparatus AP-8214
B. Test Coupons, 10 pieces each sample
(sample containers labeled with thickness in inches)
• cold-rolled steel
• annealed steel
• aluminum
• polyethylene terepthalate plastic
• polycarbonate
• brass (thick)
• brass (thin)
AP-8217
C. Storage Box 650-061
D. Attachment for force sensor 003-07916
E. Thumbscrews for Rotary Motion Sensor, 2 pieces 617-031
F. Tee handle 726-049
G. 3/8 inch socket 726-050
H. Calibration bar 648-07650
I. Experiment set-up CD-ROM 013-08999
A
B (×7)
CDE
F
G
H
I

®
Stress/Strain Apparatus Introduction
2
Introduction
The PASCO AP-8214 Stress/Strain Apparatus illustrates the relationship between
stress and strain for various materials. The apparatus stretches a test coupon (and in
some cases breaks it) while measuring the amount of stretch and force experienced by
the test coupon. Software is used to generate a plot of stress versus strain.
The Stress/Strain Apparatus requires a ScienceWorkshop or PASPORT interface,
DataStudio software, a Rotary Motion Sensor (RMS), and a Force Sensor. Included
with the apparatus are test coupons of various materials and thicknesses, a tee handle
with socket for mounting the test coupons, and a bar for calibrating the apparatus.
This manual includes instructions for calibration and data collection using the
DataStudio set-up files on the CD-ROM.
As an alternative to this manual, the CD-ROM also include a DataStudio workbook designed for
use without the printed instructions. Open Elasticity SW.ds (for ScienceWorkshop) or Elasticity
PS.ds (for PASPORT) and follow the on-screen instructions.
Additional Equipment Required for Use with
ScienceWorkshop
Sensors Part Number
ScienceWorkshop Interface (500, 700, or 750) CI-6400, CI-6450 or similar
DataStudio1
1DataStudio 1.8 or later recommended. Visit www.pasco.com to download the latest version. DataStudio Lite, the free version, is
sufficient for use with the included experiment set-up files.
See PASCO catalog or www.pasco.com
Economy Force Sensor CI-6746
Rotary Motion Sensor CI-6538
Additional Equipment Required for Use with
PASPORT Sensors Part Number
PASPORT Interface2
2Apparatus requires a single multi-port interface such as Xplorer GLX (PS-2002) or PowerLink (PS-2001), or two single-port inter-
faces such as USB Link (PS-2100) or Xplorer (PS-2000).
See PASCO catalog or www.pasco.com
DataStudio1See PASCO catalog or www.pasco.com
Force Sensor PS-2104
Rotary Motion Sensor PS-2120

®
Model No. AP-8214 Equipment Set-up
3
Equipment Set-up
1. Attach the RMS to the apparatus platform.
a. Remove the rod clamp from the RMS.
b. Place the three-step pulley onto the shaft of the RMS with the largest pulley
out. The three-step pulley should be on the “clockwise positive” side of the
RMS as illustrated (Figure 2).
c. Place the RMS on the platform as illustrated (Figure 1). Use the two
thumbscrews to fasten the RMS to the platform from beneath.
d. Seat the belt on the middle step of the three-step pulley and the groove on the
crankshaft.
2. Attach the Force Sensor to the apparatus platform.
a. Remove the hook from the Force Sensor and replace it with the force sensor
attachment.
b. Place the Force Sensor on the apparatus platform by inserting the post
through the support rod mount of the Force Sensor.
c. Insert the long thumbscrew supplied with the Force Sensor through the hole
on the Force Sensor marked “Cart” and screw it into the tapped hole in the
apparatus platform.
d. Tighten the setscrew in the support rod mount of the Force Sensor.
3. Clamp down the apparatus (optional). Use a large C-clamp to clamp the Appa-
ratus Platform to the edge of your bench or table. One side of the platform has
three feet. In order to avoid bending the platform, position the clamp directly
over the center foot.
1. Rotary Motion Sensor (RMS)
2. Force Sensor
3. Force Sensor attachment
4. setscrew
5. Stress Strain platform
6. 3-step pulley
7. belt
8. groove
9. coupon clamps
10. lever arm
11. thumbscrew
1
2
34
11
6
7
8
9
10
9
5
Figure 1: Equipment Set-up
ScienceWorkshop
PASPORT
Figure 2: Three-step
pulley on the
“clockwise positive”
side of RMS

®
Stress/Strain Apparatus Apparatus Calibration
4
4. Plug the sensors into the interface.
• ScienceWorkshop interface: Connect the Force Sensor to Channel A.
Connect the yellow plug of the RMS to Channel 1 and the black plug to
Channel 2.
• PASPORT interface: Connect the Force and Motion sensors to a multi-port
interface or two single-port interfaces.
5. Prepare DataStudio. Start DataStudio and open the activity file
Stress Strain SW.ds (for ScienceWorkshop) or Stress Strain PS.ds (for PASPORT)
located on the included CD-ROM.
Apparatus Calibration
During the experiment, as you turn the crank, force will be applied to the test coupon
causing it to stretch. However, this force will also cause the apparatus platform and
the Force Sensor to bend. The displacement registered by the RMS will be the combi-
nation of the coupon stretching and the rest of the apparatus bending.
Regardless of how much the coupon stretches, the deformation of the rest of the appa-
ratus is constant for a given force. You can measure this deformation directly by using
the calibration bar (which does not stretch significantly) in place of a coupon. In the
resulting Displacement versus Force graph, the displacement is due only to bending
of the apparatus. Later, you will subtract this calibration plot from a similar plot made
with a coupon, in which the displacement results from both bending of the apparatus
and stretching of the coupon. The difference will be a plot in which the displacement
is due only to stretching of the coupon.
Follow these steps to acquire calibration data:
1. Install the Calibration Bar.
a. Remove the nuts and clips from the apparatus platform (Figure 3).
b. Turn the crank to adjust the position of the bolts and slip the bolts through
the holes in the calibration bar. Do not replace the nuts when using the
calibration bar.
2. Place the lever arm in the starting position. Turn the crank counter-clockwise
and pull the lever arm away from the Force Sensor (Figure 4).
3. Plot Position versus Force.
a. Press the Tare or Zero button on the Force Sensor.
b. Click the Start button.
c. Turn the crank clockwise. Starting just before the lever arm comes into
contact with the Force Sensor, turn the crank very slowly. DataStudio will
start recording when the force applied to the coupon reaches 2.5 N, or 1% of
maximum (as shown in the “% Max Force” digits display).
d. Continue to turn the crank until the force reaches 100% of maximum. At this
point, DataStudio will stop recording automatically.
e. Change the name of the data run containing the calibration data to “Cal”.*
* To rename a data run,
click the run name (e.g.
“Run #1”) where it
appears in the Data List.
Wait about 1 second then
click it again. Enter the
new name. A dialog box
will appear. Select Yes. (If
a window titled “Data
Properties” appears, you
didn't wait long enough
after the first click; close
that window and try
again.)

®
Model No. AP-8214 DataStudio Set-up
5
DataStudio Set-up
1. Prepare the calculation for Calibrated Position. In the Calculator window,
define the variables for the “Calibrated Displacement(F)” calculation:
a. Drag “Displacement(t) vs Coupon Force(t) (mm)” to “Please define variable
‘Displacement’.” (Figure 5)
b. Drag “Cal” to “Please define variable ‘Cal’.” (DataStudio will display a
warning box stating that a “single run is selected”. Click the Yes button in
that box.)
Figure 3: Calibration Bar Set-up Figure 4: Start Position
Figure 5: Define Variables in Calculator

®
Stress/Strain Apparatus Data collection
6
2. Prepare the calculation for Stress. In the Calculator window, select the defined
function “Stress(F) = Force/Area”. In the Variables section, enter the cross-sec-
tional Area of the coupon in square millimeters.
3. Prepare the calculation for Strain. In the Calculator window, select the defined
function “Strain(F) = Displacement/Length”. In the Variables section, enter the
Length of the narrow part of the coupon in millimeters.
4. Close the Calculator window.
You now have a the characteristic baseline curve for your particular apparatus. You can save the
file and use it as the starting point for future experiments instead of repeating the calibration.
Data collection
1. Mount a coupon.
a. Remove the calibration bar and restore the clips and nuts.
b. Place one end of the coupon under one of the clips.
c. Adjust the crank so that the opposite end of the coupon can slip easily under
the other clip (Figure 6).
d. Tighten both nuts with the tee handle with socket. With no force applied to
the coupon, as little twist as possible should be visible in the coupon. The
clips should hold the coupon tightly enough that it will not slip when force is
applied. However, over-tightening the nuts will damage the bolts. If in doubt,
err on the side of under-tightening.
2. Place the lever arm in the starting position. Turn the crank counter-clockwise
and pull the lever arm away from the Force Sensor (Figure 4).
3. Collect Data.
a. Press the Tare or Zero button on the Force Sensor.
b. Click the Start button.
c. Turn the crank clockwise. Starting just before the lever arm comes into
contact with the Force sensor, turn the crank very slowly.*
Figure 6: Coupon Installed
* When you observe on
the Stress versus Strain
plot that the material has
been stretched beyond
the elastic region, you
can begin to turn the
crank faster.

®
Model No. AP-8214 Data Analysis
7
d. When you have finished collecting data, click Stop. (If you reach the
maximum force, DataStudio will stop automatically.) If the coupon breaks, it
should break in the middle. If the coupon breaks near the end, it was
probably twisted slightly when you mounted it, resulting in a point of higher
stress where it broke.
4. Rename the data run to identify the coupon. Use the same method you used to
rename the calibration data.
Data Analysis
On the Stress versus Strain graph, you can identify features such as the elastic region,
the plastic region, the yield point, and the break point.
To calculate Young's modulus, drag the mouse to select a data region covering the lin-
ear, lower left-hand part of the graph. (You may find that the very first part of the plot
is not linear. This nonlinearity is likely due to the straightening of bends and twists in
the coupon as force is first applied. Do not include this region in your selection.)
Click the Fit button to apply a linear curve fit to the selected data. The slope of the
line is Young's modulus in units of MPa (or MN/m2 or N/mm2).
Notes on the DataStudio Setup File
• For comparison of different materials, you can collect additional data runs with
other coupons. Note that the Stress calculation applies only to coupons of the
thickness that you entered in the Calculator window. It is easiest to compare cou-
pons of the same thickness. However, to simultaneously display stress versus
strain plots for coupons of different thicknesses, you must create a separate Stress
calculation for each thickness. Copy the existing Stress calculation exactly
(including the calculation properties), but give it a unique name (indicating the
thickness for which it is designed) and enter the applicable cross-section area for
the Area constant.
• When you create a new Stress calculation, note that there are two different calcu-
lations for Coupon Force- “Coupon Force(F)” and “Coupon Force(t)”. Always
use Coupon Force(F). The “(F)” identifies data as a function of Force, and “(t)”
as a function of time. DataStudio records data as a function of time, but this
experiment requires data to be recast as a function of Force. Whenever you create
a new calculation or graph, be certain to use only data that is a function of Force.
• When you add a new Stress calculation to the graph, it will initially appear with
time on the horizontal axis. Click the word “time” and select Strain instead.

®
Stress/Strain Apparatus Sample Data
8
Sample Data
Technical Support
For assistance with any PASCO product, contact PASCO at:
Limited Warranty
For a description of the product warranty, see the PASCO catalog.
Copyright
The PASCO scientific 012-09424B
Stress/Strain Apparatus Instruction Manual
is copyrighted with all rights reserved. Permission is
granted to non-profit educational institutions for reproduction of any part of this manual, providing the reproductions are used only in
their laboratories and classrooms, and are not sold for profit. Reproduction under any other circumstances, without the written con-
sent of PASCO scientific, is prohibited.
Trademarks
PASCO, PASCO scientific, DataStudio, PASPORT, and ScienceWorkshop are trademarks or registered trademarks of PASCO scien-
tific, in the United States and/or in other countries. All other brands, products, or service names are or may be trademarks or service
marks of, and are used to identify, products or services of, their respective owners. For more information visit www.pasco.com/legal.
Sample 1: displacement vs. force - brass.003
and.005
Sample 2: stress vs. strain - aluminum.003.
Units of slope are MPa
Address: PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone: 916-786-3800 (worldwide)
800-772-8700 (U.S)
Fax: (916) 786-3292
Web: www.pasco.com
Email: techsupp@pasco.com
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