The effect of filler particle size and orientation on the impact fracture toughness of a highly filled plasticized polymeric material
- 63 Downloads
The effect of particle size and orientation on the inherent fracture toughness of a filled plasticized polymeric material has been determined by application of linear elastic fracture mechanics. Testing was caried out in a three-point bend mode under impact conditions. The material was a triple base gun propellant consisting of a matrix of nitrocellulose plasticized with nitroglycerine and filled with particles of nitroguanidine (NQ). The crystalline NQ was used in the “as-received” form of needles and in a “ground” state. The material containing as-received NQ consistently had a higher fracture toughness than the material with ground NQ, and the toughness was a maximum when the fillers were aligned perpendicularly to the fracture surface. The impact fracture toughness was found to be virtually independent of strain rate over the range from 3 to 90 sec−1.
Seven-perforated cylindrical grains of the material containing as-received and ground NQ crystals, and the grains were tested in a pneumatic gas gun and a Hopkinson bar apparatus. The grains containing the ground NQ have been shown to be generally less resistant to fracture than the grains containing as-received NQ.
KeywordsFracture Toughness Extrusion Direction Test Span Specimen Axis Nitroguanidine
Unable to display preview. Download preview PDF.
- 1.R. Lantz and A. J. Beardell, International Jahrestagung (ICT, Karlsruhe, Germany, 1982) p. 639.Google Scholar
- 2.C. W. Fong and B. K. Moy, J. Ballistics 6 (1982) 1410.Google Scholar
- 3.L. E. Nielsen, “Mechanical Properties of Polymers and Composites” (Marcel Dekker, New York, 1974) Ch. 7.Google Scholar
- 4.S. Venzi, A. H. Priest and M. J. May, ASTM Special Technical Publication 563 (American Society for Testing and Materials, Philadelphia, 1974) p. 170.Google Scholar
- 5.J. E. Srawley, “Fracture”, Vol. 4, edited by H. Leibowitz (Academic Press, New York, 1969), Ch. 2.Google Scholar
- 8.W. R. Hoover, ASTM Special Technical Publication 563 (American Society for Testing and Materials, Philadelphia, 1974) p. 203.Google Scholar