Crack Growth Data Collection and Reduction Methodology Survey.

摘要

This methodology survey discusses crack growth data collection and reduction. Complications in the measurement process include inhomogeneity of microstructure, large deformations, and material nonuniformity complicate the analysis of cracks in propellant. Microstructure - void nucleation, growth, and coalescence at the crack tip causes sporadic crack growth. Large deformations - blunting at crack tip and large dimensional changes make measuring crack size somewhat subjective. Variation of specimen properties due to trouble maintaining uniformity during processing of large rocket grains also a problem. These complications give the crack growth rates scatter. Some of the scatter reflects real instantaneous changes in crack speed, while some are related to the measurement techniques used.