Accession Number:

ADA426593

Title:

An Electromagnetic Tool for Damping and Fatigue Analysis

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS

Personal Author(s):

Report Date:

2004-03-01

Pagination or Media Count:

109.0

Abstract:

An automated test system was developed by the USAF Turbine Engine Fatigue Facility TEFF. This system was initially designed to reduce the time and manpower required to characterize damping treatments. It is based on a digitally controlled environmental chamber with automated data acquisition and processing. Several outputs are available including identification of natural frequencies, modal damping ratios from the acquiries frequency responses, and changes in damping with response amplitude however, the TEFF additionally desires the capability to study fatigue under a free boundary condition. The system consists of a test specimen suspended by a pendulum to closely simulate free boundary conditions and to minimize the dissipation of vibrational energy. Two rare earth magnets are attached to a specimen. The magnetized end is inserted into an orthogonal magnetic field produced by an electromagnet. Alternating the current oscillates the direction of the magnetic field by 180 degrees. The effect of the electromagnets magnetic field on the specimens magnets is the application of a torque as this torque alternates directions, it excites vibration in the beam. This torque, while useful, was not fully understood. The purpose of this thesis is threefold 1. Develop an equation to predict the magnetic field produced by an electromagnetic coil 2. Develop an equation for predicting the torque exerted on the beam and 3. Experimentally validate the accuracy of these equations.

Subject Categories:

  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE