Comportamento de compósitos poliméricos de fibra de vidro sob ensaios de impacto balístico, quase-estático Punch Shear e compressão após impacto.

Abstract

In the last decades there was an increasing gain of the use of composite materials, for being lighter e stronger than monolithic materials, for using in ballistic armors, aeronautic and aerospace structures, automotive and naval industries. Thus, techniques have been developed to predict its mechanical properties, damage mechanisms and strength associated to the impact and penetration in this structures. The present work studies three different methods to obtain the behavior of a E-fiberglass/polyester composite, in the woven fabric and blanket form. In the ballistic experiments were performed tests on composite of 1, 5, 10, 15 and 20 layers of woven fabric and blanket fiberglass to find what the best configuration and ballistic efficiency of this composites. In quasi-static Punch Shear test, were possible to manufacture a test fixture to this kind of experiment, based in the literature, and it was possible to obtain the damage forms and penetration resistance of composites 5, 8, 10,12, 14, 15 and 20 layers of woven fabric and blanket. In Compression After Impact test, it was possible to manufacture a fixture based in the literature, where it was followed a design methodology and finally, it was tested a blanket 5 layers composite, with and without damage, for being evaluated compression strength this material. We can to conclude that composite with best performance in the Ballistic tests was the woven fabric 10 layers, being thinner, lower areal density and higher specific absorbed energy. In quasi-static Punch Shear test it was possible to analyze the internal fracture of composites, to describe the damage patterns presented, were obtained the hole diameters caused by puncture, the damage isotropy was analyzed by the Feret Parameters, the Energy Absorbed and Maximum load peak were evaluated, load x displacement behavior was observed and the definition of a thin and thick composite was presented. It was realized the correlation of absorbed energy, delaminated area and transversal fracture between quasi-static Punch Shear and Ballistic tests, where can be realize some differences among the tests. In Compression After Impact test can be seen the composite without damage had been a resistance higher than composite with damage and this difference it was 42,59%.