Accession Number : AD0782946

Title :   Fatigue Crack Growth in Dual-Hardness Steel Armor.

Descriptive Note : Final rept.,

Corporate Author : ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MASS

Personal Author(s) : Kula,Eric B. ; Anctil,Albert A. ; Johnson,Herbert H.

Report Date : APR 1974

Pagination or Media Count : 26

Abstract : Dual-hardness steel (DHS) is a roll-bonded composite that has particularly attractive properties as an armor material. The present report is restricted to the specific problem of the behavior of through cracks in DHS under fatigue-type loading conditions. These are cracks that might arise as a result of manufacturing defects, near welds, at stress concentrations such as bolt holes, or as a result of projectile damage during ballistic impact. In such a case, the important questions are how fast is the crack growing and what is the residual life of the component under a typical operating load spectrum. Crack growth behavior of several lots of DHS is described in terms of several variables including stress level, test temperature, frequency, and crack propagation direction. In addition, attempts are made to analyze the crack growth behavior in terms of the properties of the two elements of which the composite is comprised.

Descriptors :   *Steel, *Fatigue(Mechanics), *Armor, Crack propagation, Aircraft, Laminates, Stresses, Defects(Materials)

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE