| Autor: |
Faudree MC; Faculty of Liberal Arts and Science, Tokyo City University, Yokohama-shi 224-8551, Japan., Nishi Y; Graduate School of Engineering, Tokai University, Hiratsuka-shi 259-1292, Japan.; Kanagawa Institute of Industrial Science and Technology (KISTEC), Ebina-shi 243-0435, Japan., Salvia M; Ecole Centrale de Lyon, Ecully, CEDEX, 69134 Lyon, France. |
| Abstrakt: |
Bird strike, volcanic rock, hailstones, micrometeoroids, or space debris can cause damage to aircraft and space vehicles, therefore their composite materials must have high impact resistance to maximize safety. In a 55% wt. CaCO 3 compression molded short glass fiber polyester GFRP-BMC (bulk molded compound), shortening the nominal 6.4 mm fiber length formulation, by 30 min extended mixing, to 0.44 mm was found to increase Charpy impact values, a uc , without a change in the compression molding equipment. Specimens were cut from square panels in a spiral configuration in conformity with ASTM D 6110-02 for orthotropic panels, the flow direction approximately radially outward from the charge. At a median-fracture probability of P f = 0.50, extended mixing improved a uc by 29%, from 7.43 to 9.59 kJm -2 , and for each solidification texture angle, namely, 0 to 90 (random), 71, 45 and 18 deg, the a uc increased by 25% (6.26 to 7.86 kJm -2 ), 18% (9.36 to 11.07 kJm -2 ), 35% (7.68 to 10.37 kJm -2 ), and 20% (6.96 to 8.36 kJm -2 ), respectively. This strengthening can be explained by an increased number of thermal compressive stress sites between the glass fiber and matrix due to a difference in the coefficient of thermal expansion (CTE) during cool-down, and shrinkage, with an increased number of spaces between fibers, | S f | from 217 to approximately 2950 per mm 3 , enhancing impact energy. |
