Accession Number : ADA259783


Title :   Rain and Solid Particle Erosion Damage Mechanisms and Materials Evaluations


Descriptive Note : Final rept. 1 Oct 1983-30 Sep 1984


Corporate Author : CAMBRIDGE UNIV (UNITED KINGDOM) CAVENDISH LAB


Personal Author(s) : van der Zwaag, S ; Dear, J P ; Townsend, D ; Walley, S M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259783.pdf


Report Date : Aug 1986


Pagination or Media Count : 100


Abstract : In the initial stage of liquid impact, high pressures are developed due to compressible behaviour of the liquid. This is followed by the release of liquid in the form of high speed jets. Studies of these processes in millimeter sized spherical drops is complicated. Some features are best studied using liquid shapes other than a sphere. Sec. II describes techniques using water/gelatine layers. The gel is cut into shape and fired by a gas gun. This is viewed by high speed camera. Results are given for the shock structures, conditions, jetting and target impedance on impact. Sec. III describes methods developed for controlled single impacts. Reasonably accurate results are obtained and methods for quanitative assessment are provided. Methods for improving accuracy are provided. Sec IV provides an analysis of double layer gel particals with different elastic properties. Sec V give novel methods of recording properties at strain rates of ca. 2 x 10 to the 4th/s. Data for a range of polymers is given.


Descriptors :   *IMPACT , *POLYMERS , *RAIN EROSION , *WATER JETS , VELOCITY , SHAPE , HIGH PRESSURE , STRAIN RATE , EROSION , RAIN , CAMERAS , UNITED KINGDOM , HIGH SPEED CAMERAS , GAS GUNS , COMPRESSIVE PROPERTIES , COLLISIONS , GELS , IMPEDANCE , PROTECTIVE COATINGS , PRESSURE , DROPS , IMPACT SHOCK , COATINGS , SPHERES , ELASTIC PROPERTIES , DAMAGE ASSESSMENT , LIQUIDS


Subject Categories : Fluid Mechanics
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE