Controlled Loading Fragmentation: Experiments and Continuum Damage Modeling
Abstract
Fragmentation of metals due to high strain rate loading is a relevant topic for explosively driven metals, high velocity impacts and other energetic material scenarios. The ability to perform relevant and well-controlled experiments is a challenge. The ability to predictively model such failure and fragmentation events in dynamic continuum mechanics codes or hydrocodes is even more of a challenge. A collection of three papers are presented on the design, analysis and experiments of an explosively driven cylinder fragmentation event. The first paper describes the background of the problem and provides details of an explosively loaded cylinder geometry that establishes either plane strain or uniaxial stress conditions for failure. Parametric variations of cylinder material, initiation configuration, and cylinder dimensions are addressed. The results of this initial paper are then used to manufacture items and conduct physical experiments, which are reported in the second paper. Experiments of free-air expansion and water-recovery are conducted to extract all necessary engineering measures from which to calibrate and utilize the Johnson-Cook damage model. Experimental data obtained includes the strain-to-failure, strain-rate, fragment velocity, fragment mass, mass distributions, size distributions and approximate time of fragmentation. Diagnostics of photonic Doppler velocimetry and ultra-high speed framing cameras provide a coupled data set for high-confidence and meaningful input to the model. The last paper takes the experiment data and invokes a Weibull compensated Johnson-Cook model to explicitly calculate fragment distributions. These distributions are compared with that actually recovered.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2010
- Accession Number
- ADA538370
Entities
People
- D. E. Lambert
- J. Osborn
- J. Weiderhold
- M. V. Hopson
Organizations
- Air Force Research Laboratory