37 research outputs found
Shock behaviour of a phenolic resin
Phenolic resins are used in many aspects of everyday life, e.g. as the matrix
material for carbon fibre laminates used in the aerospace industry. Consequently
detailed knowledge of this material, especially while under shock loading, is
extremely useful for the design of components that could be subjected to impact
during their lifespan. The shock Hugoniot equation of state for phenolic resin
(Durite SC-1008), with initial density of 1.18 gcm −3 have been determined using
the plate-impact technique with in situ manganin stress gauges. The Hugoniot
equation in the shock velocity-particle velocity plane was found to be non-
linear in nature with the following equation: Us = 2.14 + 3.79up - 1.68up2.
Further, the Hugoniot in the pressure-volume plane was observed to largely
follow the hydrostatic curve. Lateral gauge measurements were also obtained. An
ANSYS Autodyn TM 2D model was used to investigate the lateral stress behaviour
of the SC-1008. A comparison of the Hugoniot elastic limit calculated from the
shear strength and measured sound speeds gave reasonable agreement with a value
of 0.66 ± 0.35 GPa obtai
On the Strength of γ-titanium aluminides during shock loading
The shock induced mechanical response of two -titanium aluminides has been investigated using the technique of plate impact. It has been found that the HEL, spall strength and shear strengths are all dependent upon the initial microstructure, with the material possessed of the duplex microstructure being the stronger. This is in agreement with quasi-static measurements. Shear strength has been observed to increase rapidly with increasing longitudinal stress. more so than in Ti-6AI-4V. indicating that the high degree of work hardening is an important factor in determining the shear strength of metallic and intermetallic materials
The role of orientation on the shock response of single crystal tantalum
The response of single crystalline tantalum to one-dimensional shock loading has been investigated as a function of crystalline orientation to the loading axis. Results show that this has a significant effect, particularly on the Hugoniot elastic limit (HEL). [100] and [111] HELs are near identical with the [110] HEL having the lowest strength. This is contrary to predictions obtained by applying the Schmid factor analysis, where the ordering was expected to be (highest strength first) [111], [110], with the [100] orientation being the softest. Adopting a more appropriate model based on uniaxial strain conditions, as was previously done successfully for FCC aluminum and copper, did not rationalize our observations. We show that a non-Schmid effective stress model, incorporating twinning/anti-twinning asymmetry, has much greater success in reproducing the experimental relative HELs magnitudes. Using this model, we make a quantitative estimation of the magnitude of non-Schmid effects and compare these to equivalent low temperature, quasi-static estimates from the literature