This paper presents the analysis of the short-crack propagation and growth in particulate composite materials by using the image correlation techniques and fracture mechanics theory. The fracture mechanics model for a long crack does not work very well with short-crack propagation when the initial crack length is less than 5.1 mm (0.2 inch). In order to investigate the short crack effect, a series of tests of particulate composite specimens with long and short cracks have been performed and the results were recorded on a video tape. These test data were analyzed to determine the strain fields near the crack tip, crack growth rate, and fracture parameters. Two initial crack lengths, 2.5 mm (0.1 inches) and 7.6 mm (0.3 inches) were used in the crack propagation tests. Images of particulate composite specimens with initial short crack in unloaded state and under loading state were digitized from the videotape. Image correlation techniques were employed to obtain the crack-tip propagation data - 2D displacements as well as inplane strains. By analyzing these test data, the crack growth rate da/dt and the stress intensity factor KI, were calculated. Log-log charts of da/dt vs. KI for both 0.1-inch and 0.3-inch initial crack test data were generated and the results were compared.
Southern Illinois University Carbondale
Zhang, Ying; Chu, Tsuchin P.; Mahajan, Ajay Mohan; and Liu, Chi Tsieh, "Analysis of Short Crack Growth in Particulate Composites" (2002). Mechanical Engineering Faculty Research. 554.