2026 ASEE Annual Conference & Exposition

The topics on the use of damping in controlling vibration, as well as on vibration suppression are typically covered in a junior (or senior) level course on mechanical vibration. We have created two student projects, addressing both topics. The first one is an analytical (numerical) project on the damping effects on the response of a two-degree-of-freedom system. The other is an experimental project to address vibration suppression. We feel that these two so called “learn by doing” activities align very well with the associated lecture modules.

The first project deals with a car suspension system, wherein a quarter model of an automobile is employed for its motion over a sinusoidal road surface. Each individual group is assigned a particular amplitude and wavelength of the assumed road surface as well as a specific damping parameter for the suspension system, while all groups use identical values of suspension and tire stiffnesses. The students are asked to derive the equations of motion for the two-degree-of-freedom system, obtain the mode shapes and the modal frequencies, the force and displacement transmissibility using MATLAB. In addition, they would obtain the responses of the system with and without damping. As the different groups present their work the students can clearly observe the effect of varying stiffness and damping parameters on the dynamic responses. This activity thus helps develop computational thinking and makes the students better equipped to tackle real world vibration problems.

The second project is to design and build a vibration absorber demonstration system. Each group is assigned a different activity within the project. The project consists of a motor with a rotating imbalance mounted on springs. A bar is attached to the base mounts that carries a mass at its end. This serves as the second spring mass system that absorbs the vibrations and minimizes the displacement of the motor. The combination of the vibration absorber and the main mass leads to a two-degree-of-freedom system. An oscilloscope is used to observe the vibration of the beam and the strain gage attached to the beam measures its displacement. A linear displacement variable transformer (LVDT) measures the displacement of the main mass. Graphing is performed using LabView. The second mass is found to absorb most of the vibratory motion of the motor. This activity thus enables the students to witness how the designed system redirects the vibrations from the unbalanced motor to another mass connected to the system, thereby suppressing the vibration of the unbalanced motor.

These two projects in combination account for 20% of the students’ grades and their responses to these projects are reported.