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Title: On the characterisation of shock-induced sliding along multi-material interfaces
Author: Collinson, Mark
ISNI:       0000 0004 5354 778X
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2015
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Experimental results utilising novel diagnostic techniques focussing on spatial resolution of shock-induced sliding phenomena at multi-material aluminium - stainless steel dry metallic contact interfaces are presented. Relative particle velocities of 50 m s⁻¹ are generated at the sliding interface via an intrinsic impedance mismatch between the material components, driven by gas gun flyer plate impact. Results are first presented for the metallography of recovered target samples from shock-induced sliding contact interfaces where the intrinsic grain structure is utilised as a fiducial marker to provide a measure of the sub-surface deformation experienced. Two distinct mutually exclusive scales of deformation were identified extending over millimetre and micrometre depths with relatively low and high free surface sliding velocities measured for these respectively using optical velocimetry. Further experimental results are presented for spatially resolved velocimetry of shock-induced sliding at planar material interfaces utilising a line-VISAR diagnostic. Experiments are conducted over 3 mm and 15 mm interface length scales with the contact interface orientated at 0.0° and 5.0° relative to the direction of loading. Specific material pairings of aluminium 1050 and aluminium 7068 paired independently with stainless steel 316 were utilised. An initial large scale experiment was found to be suggestive of the role of gaps at the contact interface, estimated to be 35 μm in size via comparison of the velocimetry data with hydrocode models. Further mesoscale experiments are suggestive of the role of re-shock and release waves generated at the contact face co-incident with the breakout of the elastic and plastic shock fronts, defining the velocimetry profile in close vicinity of the contact face over the timescales measured.
Supervisor: Eakins, Daniel Sponsor: Atomic Weapons Establishment
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral