Apparatus for Demonstrating Wave Motion in Structures

 

Sponsor:  Brian Zellers, Penn State University

Course:  ME 415 Spring 2005

Instructor:  Prof. Gary Koopmann

Team:  The Wavers  -  Jared Davis, Tom Digan, Jason Klimczak, Andrew Parise                                                     

Wave motion apparatus ready to be transported

 

Design Criteria:

Modular and Portable

Adjustable System Parameters

Lights to Emphasize Motion

Theoretical Verification of System

Cost Effective

 

 

 

 

 


Wave motion apparatus ready for demonstration

 

 


                                                                                                                               

Project Background                                                                                                

This project will be used as a classroom model to show students how waves travel through structures.  It will also show how a force on one part of a structure can affect the rest of the structure.  There are many forms of waves that can be analyzed and demonstrated using different types of models.  This project, however, deals strictly with the motion of transverse waves.  The wave motion demonstrator is very portable and has the ability to be easily transported from one building to another.  In addition to being portable, it also has adjustable boundary conditions and the ability to change masses and the location of input forces.  Changing these parameters will ultimately help students in the classroom see how each element, when changed, affects the behavior of the system.  Students should be able to see different modes of vibration for the system and how these modes vary with the different frequencies that can be inputted into the system.  The modes also vary when the system parameters are changed at a given frequency, as is demonstrated by this project.

 

 

Executive Summary

The chosen design has 20 aluminum rods clamped to a torsion wire which is suspended by a wooden oak base.  The rods act as the system’s masses and the torsion wire acts as the springs.  LED’s were mounted to the ends of the rods in order to emphasize the motion of the wave moving across the apparatus.  Any one of the rods can be driven via a DC motor with a crank/connecting rod at variable frequencies, creating a wave that will propagate down the torsion wire and through the system.  The frequency of the motor is changed by using a variable voltage source to vary the speed of the motor.  A 3V AC/DC adapter is used to convert AC current from a wall outlet to usable DC current, which powers the 20 LED’s.  Extra weights can also be added to the aluminum rods to change the total mass of the system, and any one of the rods can be held fixed to change the boundary conditions.  These adjustable parameters allow the user to change the system’s output.  The entire system is enclosed inside a wooden box with a lid which protects the apparatus and provides easy transportation.

 

 

Created 04/21/05