Accession Number:

ADA068440

Title:

Impact Damage Thresholds in Brittle Materials Impacted by Water Drops.

Descriptive Note:

Final rept. 1 Mar 75-31 Dec 78,

Corporate Author:

ROCKWELL INTERNATIONAL THOUSAND OAKS CALIF SCIENCE CENTER

Personal Author(s):

• Evans,A. G.
• Ito,Y. M.
• Rosenblatt,M.

Report Date:

1979-03-01

Pagination or Media Count:

40.0

Abstract:

The damage threshold for brittle materials impacted by water drops has been studied by using a combination of analytic and numerical approaches to obtain solutions for the impact stress fields and dynamic stress intensity factors. It has been shown that expressions for the damage threshold, which consists of the activation of pre-existent surface microcracks, can be derived from these solutions. The expressions identify three types of behavior, depending upon the adjacence of the pre-existent cracks to the impact center, vis-a-vis their size, and describe the respective roles of the three important target parameters, the fracture toughness, the elastic wave velocity and the pre-existent flow size. An absolute damage threshold has also been defined. The conditions at this threshold are demonstrated to be reasonably consistent with available threshold measurements. Author

Descriptors:

• *STRESS ANALYSIS
• *CERAMIC MATERIALS
• *MATHEMATICAL ANALYSIS
• ACTIVATION
• PROJECTILES
• THRESHOLD EFFECTS
• IMPACT TESTS
• STRESS TESTING
• DAMAGE ASSESSMENT
• SURFACE PROPERTIES
• DROPS
• DYNAMIC LOADS
• RAIN EROSION
• MICROCRACKING

Subject Categories:

• Ceramics, Refractories and Glass
• Numerical Mathematics
• Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE