Accession Number : ADA305025

Title :   Dynamic Impact Response Behavior of Polymeric Materials. 2.

Descriptive Note : Final rept. 26 Aug 77-26 Oct 78,

Corporate Author : GENERAL ELECTRIC CORPORATE RESEARCH AND DEVELOPMENT SCHENECTADY NY

Personal Author(s) : Hillig, William B.

PDF Url : ADA305025

Report Date : MAR 1979

Pagination or Media Count : 80

Abstract : This report describes the work performed in the 14-month period beginning August 26, 1977, relating to a basic study of the materials response processes primarily of polymethylmethacrylate PMMA, polycarbonate PC, and epoxy resins during a ballistic impact encounter. Experimental impact data on PMMA, PC, and epoxy have been obtained using 19 and 4.5 mm diameter strikers at impact velocities of 1.77 and 2.93 m/sec. The data have been analyzed. The irreversible work absorbed by the specimen for a given impact energy, the depth of penetration, and the pulse duration increase in the order PMMA < epoxy < PC, but the irreversible energy per unit penetration is the reverse of this series. The apparent crater depth at the time of projectile/specimen separation shows less regular relative behavior. Cinematographic documentation of the impact process was made of PC and PMMA impacted by a 4.5 mm steel ball at an impact velocity of 120 m/sec. The camera speed was 2 x 10(exp 5) frames/sec. Densification could be clearly observed developing in the case of PC, and less distinctly so in the case of PMMA. Evidence for crack formation during the projectile rebound phase was noted for the case of PMMA. Some shrinkage of the densified zone appeared to occur subsequent to the impact. In another experiment, an impact pulse was obtained on a PMMA specimen struck by a 4.5 mm steel ball at 85 m/sec. This result indicates that attention must be given to eliminating or correcting the taper-on effect at the leading edge of the sensed pulse. (MM)

Descriptors :   *GLASS, *TERMINAL BALLISTICS, *PLASTICS, VELOCITY, POLYMERS, PROJECTILES, IMPACT TESTS, DYNAMIC RESPONSE, MODULUS OF ELASTICITY, POLYMETHYL METHACRYLATE, STEEL, IMPACT STRENGTH, PULSE RATE, PENETRATION, ALUMINUM, LEADING EDGES, AMPLITUDE, EPOXY RESINS, SILICON CARBIDES, POLYCARBONATES, CRATERS, SHRINKAGE, HIGH SPEED CAMERAS, CINEMATOGRAPHY.

Subject Categories : Ceramics, Refractories and Glass
      Plastics
      Ballistics
      Photography

Distribution Statement : APPROVED FOR PUBLIC RELEASE