Accession Number : ADP003103

Title :   A Plate Impact Experiment for Studying Crack Initiation at Loading Rates K(I) Approximately 10(8) MPa m/s,

Corporate Author : BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING

Personal Author(s) : Clifton,R. J. ; Ravichandran,G.

Report Date : OCT 1983

Pagination or Media Count : 11

Abstract : A symmetric plate impact technique is being developed for establishing the critical conditions for dynamic fracture initiation at extremely high loading rates. The specimen consists of a circular disc with a mid-plane, prefatigued, edge crack that has propagated halfway across the diameter. A compressive pulse propagates through the specimen, reflects from the rear surface, and subjects the crack plane to a step tensile pulse. The motion of the rear surface of the specimen is monitored with a laser interferometer system in order to determine the loading time required for crack extension to begin. Using this time in the elastodynamics solution of the stress wave diffraction problem, one can obtain the critical value of the stress intensity factor for dynamic fracture initiation. Preliminary experiments are being conducted on SAE 4340 VAR steel.

Descriptors :   *Steel, *Plates, *Crack propagation, *Loads(Forces), *Impact tests, *Experimental data, Cracking(Fracturing), Structural properties, Tensile properties, Stress concentration, Compressive properties, Diffraction, Fatigue(Mechanics), Gun barrels, Time dependence, Heat treatment, Austenite, Martensite, Microstructure, Yield strength, Acoustic impedance, Equations, Geometry, Configurations, Symposia

Distribution Statement : APPROVED FOR PUBLIC RELEASE