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Chapter 17: D. Testing Methods 191
intended. Minimizing the bugs in the product will minimize the cost of service
and maintenance after sale, which will build product reputation and provide
the ability to compete in the marketplace.
Methods of Functionality Testing
The most common type of functionality testing is performed on software packages.
This topic will be covered in Section 5 of this chapter. Other functionality
testing is performed in manufacturing facilities to ensure that products can be
exposed to the maximum tension, torque, and/or compression.
Tension. Tension is the act of stretching an object using an external force. Test
engineers use test equipment that can apply a large amount of force on products
and measure the magnitude and duration of the force on the product. Figure 17.11
illustrates the main components of a tension test machine.
Torque. Torque is a vector that measures the tendency of a force to rotate an object
about some axis (Sexway and Jewett 2003). This type of test is performed on an
object to measure the magnitude of torque that can be applied on that object before
it breaks. Torque can be calculated by multiplying the force applied to a lever by
its distance from the lever’s fulcrum (see Figure 17.12), which can be represented
by the following formula:
t = r × F
Force measurement
Part III.D.3
Grips for holding
specimen firmly
Fixed
head
Test specimen
Fixed
head
Thickness 1/8"
Constant rate
of motion
Figure 17.11 Tension test machine.