Composites impact tests

Component Composition, wt % Heat of reaction, kj/g" Gas volume, cmVg Relative brisance, % TNT Ignition temp, °C Impact test, % TNT... 

C. C. Chamis, M. P. Hanson, and T. T. Serafini, Impact Resistance of Unidirectional Fiber Composites, in Composite Materials Testing and Design (Second Conference), H. T. Corten (Chairman), Anaheim, California, 20-22 April 1971, ASTM STP 497, American Society for Testing and Materials, 1972, pp. 324-349. 

Bowles, K.J, (1988). The eorrelation of low-vclocity impact resistance of graphite fiber reinforced composites with matrix properties. In Composite Materials Testing and Design (8th Conference), ASTM STP 972 (J.D, Whitcomb ed.), ASTM, Philadelphia, PA, pp. 124-142. 

Figure 8.15 Schematic illustration of Charpy impact test. Reprinted, by permission, from P. K. Mallick, Fiber-Reinforced Composites, p. 249. Copyright 1988 by Marcel Dekker, Inc.

In order to safely use Cyclonite for loading projectiles, the expl has to be desensitized to such an extent that its impact test value would be comparable to that of either PA or TNT. One of the ways to achieve desensitization of RDX is to coat the particles with wax or a less sensitive expl such as TNT. A major development during WWII was the development of binary, ternary and other expl mixts using the sensitive very powerful explosive RDX. Some of the compositions developed for military and industrial applications include ... 

New possibilities appeared with the use of nonbreaking impact tests. The question is how a high-speed striker with a low energy can induce damages and what the residual energy is. These tests are very often performed on composites with thermosetting matrices. 

Noninstrumented Izod Testing. The impact strength, reported in joules per meter of notch, was measured at temperatures between 25° and — 30°C. The samples were cooled to the test temperature using a Lauda Kryostat and equilibrated in the Kryostat for at least one and one half hours prior to testing. Five to seven seconds were required to remove a sample from the Kryostat, mount, and perform the Izod impact test. Ten samples of each composition were tested at each temperature. 

Many applications of ceramic composites will expose the material to impact damage. Here again, the amount of work which has been done in this arena is limited, and needs to be increased. Impact tests can be performed using drop towers or Charpy impact testing apparatus. Such measurements have been done at room temperature30 and the apparatus can be adapted for use at elevated temperatures. 

Impact and Tensile Testing. A number of mechanical tests were carried out on test bars cut from the molded sheets. For the impact tests six sample bars were cut for each mixing and composition condition while for the tensile tests four test specimens were prepared. The reported results are average values as determined from that number of test bars. The tensile tests were run at a crosshead speed of 0.2 inch/min. Table I lists the results for the impact and tensile tests of the dry blended mate-... 

Tough-Brittle Transition of Glass Fiber Composites by Impact Testing... 

Cain, P.J. (1987) In Instrumented Impact Testing of Plastics and Composite Materials. pp. 81-102, S.L. Kessler, G.C. Adams, S.B. Driscoll, and D.R. Ireland (Eds). American Society for Testing and Materials, Philadelphia. 

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