Caracterização mecânica de Poliamida6 reforçada com fibra de vidro

Abstract

The automotive industry is passing through a new era by electric vehicles, which come from a strong environmental appeal, but these vehicles carry large amounts of battery due to the necessity of delivering a range close to current combustion vehicles therefore the appeal for reduction mass in vehicles has never been so strong. A material with a high strength potential aligned with a very low density is composite materials, especially fiber reinforced polymers. Aligning first and foremost to cost-effectiveness and ease of procurement is fiberglass reinforced polyamide 6, this material was even one of the first materials developed in its category. A polyamide 6 bar sample was provided for the study, manufactured by extrusion with 30% fiberglass. Fostering the study of this material for structural applications in the automotive industry, it was sought to characterize the material thus questions about the composite materials were answered, for this purpose differentiated tests were defined to treat several properties relevant to the application. The modulus of elasticity and Poisson's coefficient were obtained from impulse excitation. Giving an idea about anisotropy and understanding the matrix and fiber issues, as well as issues such as the fracture mechanisms of the material a test on a fragile fracture region was made via Scanning Electron Microscopy (SEM), for the analysis of tensile strength, the flexural test was used, obtaining the modulus of rupture and elasticity, which were compared with the values found experimentally and those raised by the supplier. Last but not least, a fracture toughness test was performed, this test do not have a large study in this material category, mainly using compact specimens, but these data are very important for structural materials, from this test a discussion about the importance of strength aligned with a fail-safe property conditions was raised, as well as an analysis of the relationship of this property to the change in thickness. Some conclusions were raised, as the difference is low between the properties with respect to its direction, for a randomly extruded 30% fiber composite material, the development for the application of this material can be simplified, treating it as homogeneous, remembering that there will be a minimal error that will be absorbed in the adopted safety factors. The major failure mechanism was from and through the matrix phase, with the presence of fracture layers and pores. Second was the fiber breakage and then its retraction. The rupture modulus values showed high reliability through the Weibull modulus analysis, which reinforces the idea of the possibility of simplifying the development of the material (homogeneous), since the specimens were from different regions of the bar and presented the same property. The geometry should be a key role in the development of composite materials.