EVALUATION OF THE CRACK GAGE AS AN ADVANCED INDIVIDUAL AIRCRAFT TRACKING CONCEPT
Abstract
The results of an experimental and analytical investigation on the advanced approach for employing the crack gage as an aircraft fatigue monitoring device are discussed in this report. The crack gage is a simple device which provides a convenient means for determining the potential damage, that is crack growth, in a structure, since crack extension in the gage is a result of loads on the structure which cause the structural damage. Two models were examined to generate transfer functions relating gage and structure crack lengths. The Double Gage Model (DGM), which simultaneously employs two crack gages, was analyzed and evaluated to yield a load dependent transfer function. Analytical results are compared with available experimental data for constant amplitude loading as well as for various spectrum loadings. The Side Grooved Gage Model (SGGM), in which the introduction of deep side-grooves promotes plane strain constraint to thin sections, was analyzed and verified to yield a thickness independent transfer function. Experimental results are reported for various gage shapes tested under constant amplitude loadings, with and without peak overloads. Comparison of the analyses and the experimental data is made.
Degree
Ph.D.
Subject Area
Aerospace materials
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