Instant flywheel stop
SOM-TOR-02
A flywheel with a mass of 6 kg and a diameter of 360 mm is mounted at the lower end of a steel shaft with a diameter of 16 mm and a length of 1000 mm. The shear modulus of steel is 78 GPa. The system rotates with an angular velocity of $\omega=28$ rad/s. Determine the maximum shear stress in the shaft material if its upper end is stopped instantaneously.
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About this task
This task examines the torsional response of a steel shaft when a rotating flywheel is stopped instantaneously. Students calculate the kinetic energy stored in the rotating system, determine the maximum torque developed in the shaft, and evaluate the resulting peak shear stress. The problem combines rotational dynamics, strain energy, and torsion of a solid circular shaft, helping students connect energy methods with stress analysis in machine elements. It is suitable for strength of materials, machine design, and engineering mechanics courses covering torsional impact and rotating systems.