Dynamic Fracture behavior of Structural Materials.
Abstract
To ensure safe design of Air Force structures, it is necessary to understand the mechanics of high-rate fracture and to have a knowledge of the dynamic fracture properties of component materials. In accord with this need, a research program is being conducted at SRI with the goals of developing a test procedure for obtaining reliable dynamic initiation toughness values and establishing the relationship between dynamic initiation and dynamic propagation toughness. This annual report summarizes the progress and results of the fourth research year. The capabilities of the one-point-bend impact test (1PBT) conceived by Kalthoff et al. and furether develped during previous years of this program were extended in two ways during this fourth research year. By adding ballast plates to the ends of a specimen plate we showed that the 1PBT could be applied to lower density materials and smaller specimens than heretofore possible. Second, we developed a model of the post-instability behavior of the impacted specimen that allows the test to be used to assess crack propagation as well as crack initiation behavior. To compare dynamic initiation and propagation toughness, we performed a series of one-point-bend experiments in which KId and KID were measured on the same specimen. The propagation toughness values were dependent on crack velocity and propagation distance, and were much larger than the initiation toughness. Keywords: Dynamic fracture, Incubation time.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 25, 1985
- Accession Number
- ADA154568
Entities
People
- D. A. Shockey
- J. H. Giovanola
Organizations
- SRI International