Teaching modal analysis with mobile devices

Abstract

An inexpensive system capable of performing modal analysis of laboratory models and full-scale structures was employed in both a laboratory and field experience in a 400/500-level bridge rating elective course. The system, comprised of an electromechanical shaker and an array of 12 iPods, allows for an introduction to modal testing of bridges and other structures in an active and highly physical way. A laboratory module employing the system is described. Indirect and direct assessment of student learning is reported along with student evaluation of the module. In general, students perceived full-scale testing, numerical modeling, and discussion of theory as more valuable than lab-scale testing in supporting their learning. Their confidence in demonstrating their understanding was high for lower-cognitive-level objectives and lower for application-level objectives. Their ability to demonstrate their learning was relatively inconsistent with their own perceptions of their ability. Given the demonstrated learning and high perceived value of full-scale field testing, the effort to deploy a shaker and relatively simple data collection system using mobile devices was deemed an effective way of introducing students to experimental modal analysis and resonance testing.