Accession Number : AD0778822

Title :   Exploratory Investigation of Rapid Crack Propagation and Crack Arrest.

Descriptive Note : Final rept. 15 Dec 71-7 Feb 73,

Corporate Author : BOEING AEROSPACE CO SEATTLE WASH

Personal Author(s) : Shah,R. C.

Report Date : AUG 1973

Pagination or Media Count : 104

Abstract : The experimental program was undertaken to study aircraft structural alloys. Materials tested included 2219-T851 and 7075-T6 Aluminum, 6Al-4V beta-annealed Titanium, 9Ni-4Co-0.2C and 4340 steel alloys. Tests were conducted with radially flared and uniform height DCB (Double Cantiler Beam) specimens containing either sharp cracks or notches with finite root radii. The specimens were instrumented to measure crack velocity, crack length, crack opening displacement, instantaneous load, strain and crack lengths and the stress intensity factors at the initiation and the arrest of the crack propagation. An instrumentation system for the measurement of crack velocities from zero to several thousands of feet per second is presented. Experimental results indicate that a cracked DCB specimen of any configuration under static loading is not suitable for investigating the dynamic behavior of rapidly running cracks or crack arrest conditions. Recommendations for suitable test specimens are provided. (Modified author abstract)

Descriptors :   *FRACTURE(MECHANICS), *ALUMINUM ALLOYS, *TITANIUM ALLOYS, *STEEL, CRACK PROPAGATION, AIRCRAFT, NUMERICAL ANALYSIS, TEST EQUIPMENT, DYNAMIC TESTS

Subject Categories : Aircraft
      Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE