Test coupon specifications, Theory – PASCO AP-8214A Stress_Strain Apparatus User Manual
Page 3
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M o d e l N o . A P - 8 2 1 4 A
0 1 2 - 1 3 2 8 2 A
I n tr o d u c t i o n
3
Test Coupon Specifications
The data below are intended as a general guide only and do not necessarily represent results that may be obtained.
The units for tensile strength and modulus of elasticity are megapascals (MPa or 10
6
N/m
2
) and pounds per square
inch (psi).
AP-8222 Plastic Test Coupons
AP-8223 Metal Test Coupons
Theory
.
A stress-strain tensile test measures the amount of stretching force
applied to a sample of material, and the amount of stretch of a mate-
rial. Stress (
σ) is the ratio of force (F) per unit of cross-sectional area
(A). Strain (
ε) is the ratio of the change of length (l) compared to the
original length (L). A stress-strain curve is a graphical representation
of the load applied and the deformation of the sample. The curve var-
ies from material to material.
Ductile materials like metal have a linear stress-strain relationship up
to a point. The slope of the linear part of the stress-strain curve is
called “Young’s modulus” or the modulus of elasticity (E) and is a
property used to characterize materials.
Item
HIPS
nylon 6 (+ 15% glass)
ABS
polypropylene
Color code
orange
black
blue
white
Cross-sectional area
2.482 mm
2
2.482 mm
2
2.482 mm
2
2.482 mm
2
Tensile strength
23 MPa/
3410 psi
98 MPa/
14000 psi
47 MPa/
6800 psi
34 MPa/
4900 psi
Tensile elongation
40%
2.5%
20%
9%
Modulus of elasticity
2000 MPa/
280000 psi
2900 MPa/
420000 psi
2300 MPa/
380000 psi
1900 MPa/
239000 psi
Item
cold-rolled steel
annealed steel
aluminum
brass (thin)
brass (thick)
Cross-sectional area
0.303 mm
2
0.303 mm
2
0.303 mm
2
0.303 mm
2
0.506 mm
2
Tensile strength
620 MPa/
90,000 psi
300 MPa/
44,000 psi
145 MPa/
21,000 psi
430 MPa/
44,000 psi
430 MPa/
44,000 psi
Tensile elongation
none
42-45%
6%
25%
25%
Modulus of elasticity
200,000 MPa/
29,000,000 psi
200,000 MPa/
29,000,000 psi
69,000 MPa/
10,000,000 psi
117,000 MPa/
17,000,000 psi
117,000 MPa/
17,000,000 psi
Fig. 4: Stress-Strain curve