Dynamic Fracture Initiation and Propagation in 4340 Steel under Impact Loading,
Abstract
Dynamic fracture initiation and propagation in 4340 steel was investigated experimentally using the optical method of reflected caustics combined with high speed photography. A new crack propagation testing configuration consisting of a three point bend specimen loaded in a drop weight tower was used. It was found that prior to crack initiation the stress intensity factor time record calculated using the dynamic tip load and a static formula disagrees with the actual stress intensity factor measured by caustics. During crack propagation, the crack tip velocity and stress intensity factor time records varied smoothly and repeatably allowing for a straightforward interpretation of the data. The experiments show that for the particular heat treatment of 4340 steel used, the dynamic fracture propagation toughness depends on crack tip velocity through a relation that is a material property. Keywords: Dynamic fracture initiation, Dynamic crack propagation, Caustics, 4340 steel, High-speed camera, Stress-intensity factor, and Three point bend specimen.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1986
- Accession Number
- ADA173084
Entities
People
- Alan T. Zehnder
- Ares J. Rosakis
Organizations
- California Institute of Technology