C-130 Scratch Strain Gage Recording Program,
Abstract
To investigate the potential of a mechanical strain gage (the Prewitt Scratch Strain Gage, commonly called the scratch gage) for future fatigue damage monitoring on individual aircraft, twenty-two C-130 aircraft were each instrumented with two scratch gages on the external surface of the left wing. Other objectives included investigating the permanence of scratch gage installations, the installation and maintenance performance of Air Force personnel, the gage functioning in various environments, and the data collection logistics. During a 3-month recording period while Air Force personnel handled all maintenance and data acquisition tasks at all but one of 15 air bases, strain data were recorded on 442 targets (gage recording discs). On the average each target recorded about 12 hours of data corresponding to about three flights. Of these targets, 88.5 percent had processable data. However, in the initial installations, approximately 66 percent of the scratch gages and covers were lost because of inadequate bonding. After the bonding was made effective, the gage mean-time-between-failure was 80 hours. The data presentation consists basically of summary tables of mean and alternating stresses and of exceedance (time to reach or exceed a given level) curves of maximum stress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1974
- Accession Number
- AD0917939
Entities
People
- Arturo V. Serrano
- Curtis A. Jackson
- Larry E. Clay
- Ronald I. Rockafellow