PASCO AP-8214A Stress_Strain Apparatus - Manual (Page 8)

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S t r e s s / S t r a i n A p p a r a t u s 0 1 2 -1 3 2 8 2A D a t a c o l le c t i o n
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3. Prepare the calculation for “Strain(F)”. First, measure the length
of the narrow part of the test coupon. (The nominal length is 80 mm
for the metal coupons and 18 mm for the plastic coupons.) In the
Calculator window, select the defined function “Strain(F) = Dis-
placement/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.
• Remove the calibration bar from the bolts. Replace the spring, clamp
top, concave washer, convex washer, flat washer, and hex nut onto
the bolts (Figure 11).
• Place one end of a coupon under one of the clamp tops.
• NOTE: The plastic test coupons have ridges on their top sides. Place
the end of the plastic test coupon under the clamp top with the ridge
on top.
• Adjust the crank so that the opposite end of the coupon can slip easily under the other clamp (Figure 12).
• Tighten both nuts with the tee handle with socket. With no force applied to the coupon, as little twist as pos-
sible should be visible in the coupon. The clamps 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 so that there is a small gap between the end of the Force Sensor Attachment and the
lever arm..
3. Collect Data.
• Press the Tare or Zero button on the Force Sensor.
• Click the Start button in DataStudio.
hex
nut
flat washer
convex
washer
concave
washer
clamp
top
spring
bolt
Fig. 11
coupon
goes
here
Fig. 12: Coupon Installed
coupon
gap
clamp
clamp
lever arm
crank