Using Impact Modulation to Identify Loose Bolts on a Satellite
Abstract
This report investigates the use of Impact Modulation (IM) as a means for detecting loose bolts in a satellite structure. First, a two-beam, one-bolt assembly is studied to establish guidelines for implementing IM. Then, theoretical models are developed to provide a basis for applying IM to bolted joints. Two analysis methods for identifying loose bolts within a structure are then proposed. These methods are demonstrated on a three-beam, two-bolt structure; a four-beam, three-bolt structure; and a realistic satellite structure. The results of IM testing on the two-beam, one-bolt assembly showed that the nonlinear response of the system is significantly affected by the underlying linear characteristics of the system and that IM is an effective method for differentiating the responses of the bolted structure with different bolt torque levels. The first analysis method was able to identify the presence of loose bolts within increasingly complex structures without the use of historical data by quantifying the difference in response amplitudes at the natural frequencies and those at the sideband frequencies across an array of impact locations. The second analysis method tracked changes in bolt torque by comparing the area under the response spectra in the modulation range to a baseline reference.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 21, 2011
- Accession Number
- ADA553361
Entities
People
- Doug Adams
- Janette Jaques
Organizations
- Purdue University