Research Scientist, General Dynamics Corporation, Fort Worth, Tex.
Professor, Virgina Polytechnic Institute and State University, Blacksburg, Va.
Pages: 20 Published: Jan 1982
A wide variety of nondestructive evaluation (NDE) techniques was used to characterize the damage state of FP/aluminum (FP/Al) composite materials. (FP/Al is a material manufactured by Du Pont containing alumina fibers in an aluminum matrix.) The NDE techniques used in the present work were X-ray radiography, ultrasonic C-scan and pulse-echo, stiffness change, eddy current, thermography, acoustic emission and edge replication. The capabilities of these NDE methods to determine the in situ and fatigue damage in this material system were evaluated. After thorough initial nondestructive characterization, the specimens were subjected to several different mechanical test procedures. The mechanical tests were used to initiate damage and to monitor the subsequent material response. At several intermediate intervals in the damage development process, the specimens were removed from the test machine and resubjected to the same nondestructive characterization procedures. Three-point bending was the primary loading mechanism used to initiate and grow damage. To control the location of damage initiation, notches were machined into several specimens. Longitudinal cracks propagating from these notches were closely monitored and correlated to a reduction in material properties.
composite materials, metal matrix composites, nondestructive evaluation (NDE) techniques, damage state, material response, three-point bending, fatigue testing, flexural rigidity
Paper ID: STP28488S