MOMENT OF INERTIA TEST LAB OBJECTIVE:
The objective of this test is to determine the mass moment of inertia of a test object utilizing an experimental method. The test object should be chosen such that an analytical result can be estimated.
Each lab section will conduct total of four tests: two tests to estimate the mass moment of inertia of the two triﬁlar pendulums and two tests (one on each triﬁlar pendulum) of a regularly shaped object. The test of a regularly shaped object on the larger triﬁlar pendulum will be conducted by each group on a common object (50-100 pounds) supplied by the Teaching Assistants. The other test of a regularly shaped object will be conducted individually by each lab group on a part of their choosing. This test will be conducted with a smaller object (5-20 pounds) on a smaller triﬁlar pendulum Each testing procedure will utilize a triﬁlar (three wire) pendulum and will require that the center of gravity and principal axis, about which the mass moment of inertia is to be estimated, are known or can be estimated easily. The triﬁlar pendulum acts like a single degree of freedom torsional pendulum. The single degree of freedom characteristics of the triﬁlar pendulum can be used to determine the mass moment of inertia in question. The procedure involves the following steps for each pendulum, at a minimum:
• The natural frequency of the triﬁlar pendulum can be determined experimentally
by measuring the period of oscillation of the pendulum. The period of the triﬁlar pendulum can be measured accurately by using an accelerometer mounted tangentially on the platform of the pendulum in order to measure the tangential acceleration during rotation. Since the theoretical equations are approximated using the small angle assumption, the initial displacement (rotation) of the pendulum should be small (no more than 10 degrees).
• Choose a part that is regular in dimension and material so that a reasonable
analytical prediction of...