Fracture and Failure at and Near Interfaces Under Pressure

摘要

This work addressed the failure behavior of solid propellant rocket fuels through crack propagation. The objective of the study was to: (1) develop the means for measuring large deformation fields around the tips of stationary or slowly moving cracks, to develop realistic data for comparison with improved analytical results, and to; and (2) initiate a new computational approach for stress analysis of cracks at and near interfaces, which can draw on the expanding capabilities of parallel processing. Important results are that: (1) strain inhomogeneities are much more pronounced than hitherto anticipated; they are associated with the granular microstructure and are characterized by spatial variations on the sub-millimeter size scale; (2) these strain inhomogeneities dominate the deformation field around a crack tip and control the fracture process; cracks connect statistically distributed regions of high strain, if they are reasonably close to the crack propagation line; (3) a domain of 1-3 mm in extent around the crack tip is totally dominated by this highly inhomogeniously deformed material, with the adjacent material undergoing large nonlinear deformations; and (4) the disintegrating region close to the crack tip is not likely to be describable in continuum terms, and needs to be modeled in a discrete fashion.