A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - The initial stages of deformation in metals subjected to repeated liquid impact

Abstract

Experiments have been carried out to investigate the initial stages in the deformation of metals due to repeated liquid impacts. The initiation of damage is discussed and a comparison made with the initial stages of deformation in metals subjected to similar hydrodynamic loading conditions due to the action of shock waves in a liquid. The destructive role played by the rapid flow of liquid across the surface of a specimen after impact is also described.

Introduction to the microscopy of erosion

“…Optical examination of the surface at high magnification is generally of little use since eroded surfaces tend to be rough and insufficient depth of field can be obtained. An exception is provided by the early stages of the cavitation or liquid impact erosion of a plane surface, where small deviations from flatness can be detected with sensitivity by Nomarski interference contrast microscopy (Thomas, 1966;Hansson & Morch, 1979).…”

Analyse du mécanisme de l'érosion de cavitation

“…Lors des premiers essais utilisant ce dispositif, on ne savait si l'érosion observée était imputable à un pur ef1'et de choc liquide-soliTle ou à une cavitation secondaire lors de l'entrée de l'éprouvette dans le jet [2] [11], [12], ont montré l'existence d'une onde de choc prenant naissance à la frontière liquide-solide. Le choc se trouve inll11édiatement suivi d'une surpression locale très élevée ct dont la durée dé-pend du temps de réflexion de l'onde sur les surfaces libres du jet.…”