19th Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 60, Number 8
Sunday–Friday, June 14–19, 2015;
Tampa, Florida
Session T6: Inelastic Deformations, Fracture and Spall IX: Brittle Ceramics
11:15 AM–12:45 PM,
Thursday, June 18, 2015
Room: 8/9/10
Chair: James Hogan, Johns Hopkins University, Min Zhou, Georgia Institute of Technology
Abstract ID: BAPS.2015.SHOCK.T6.1
Abstract: T6.00001 : High Speed Dynamics in Brittle Materials
11:15 AM–11:45 AM
Preview Abstract
Abstract
Author:
Stefan Hiermaier
(Fraunhofer EMI)
Brittle Materials under High Speed and Shock loading provide a continuous
challenge in experimental physics, analysis and numerical modelling, and
consequently for engineering design. The dependence of damage and fracture
processes on material-inherent length and time scales, the influence of
defects, rate-dependent material properties and inertia effects on different
scales make their understanding a true multi-scale problem. In addition, it
is not uncommon that materials show a transition from ductile to brittle
behavior when the loading rate is increased. A particular case is
spallation, a brittle tensile failure induced by the interaction of stress
waves leading to a sudden change from compressive to tensile loading states
that can be invoked in various materials.
This contribution highlights typical phenomena occurring when brittle
materials are exposed to high loading rates in applications such as blast
and impact on protective structures, or meteorite impact on geological
materials. A short review on experimental methods that are used for dynamic
characterization of brittle materials will be given. A close interaction of
experimental analysis and numerical simulation has turned out to be very
helpful in analyzing experimental results. For this purpose, adequate
numerical methods are required. Cohesive zone models are one possible method
for the analysis of brittle failure as long as some degree of tension is
present. Their recent successful application for meso-mechanical simulations
of concrete in Hopkinson-type spallation tests provides new insight into the
dynamic failure process. Failure under compressive loading is a particular
challenge for numerical simulations as it involves crushing of material
which in turn influences stress states in other parts of a structure. On a
continuum scale, it can be modeled using more or less complex plasticity
models combined with failure surfaces, as will be demonstrated for ceramics.
Models which take microstructural cracking directly into account may provide
a more physics-based approach for compressive failure in the future.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2015.SHOCK.T6.1