Title: EFFECT OF FLOW-INDUCED CRYSTALLIZATION AND MORPHOLOGICAL CHANGES ON THE MECHANICAL BEHAVIOR OF LONG DISCONTINUOUS GLASS FIBER POLYAMIDE COMPOSITE
Authors: Siavash Sattar, Diego Pedrazzoli, Mingfu Zhang, Sergey G. Kravchenko, Oleksandr G. Kravchenko
Abstract: This study describes the effect of the flow-induced orientation distributions on the tenasile properties of the long discontinuous glass fiber polyamide 6 composite (organosheet). The reorientation of bundles results from the anisotropic flow of the molding compound, affecting the mechanical properties. Furthermore, the orientation development that occurred in Nylon 6 phase due to the flow effect during molding affected the properties of the organosheet. In this study, the effect of molding-induced flow on the mechanical behavior of organosheet was studied. The full mold coverage and partial center charge of 80%, 60%, 50%, and 40% were compression molded. Tensile specimens were cut in the flow direction and tested to compare the effective tensile properties (modulus and strength). The changes in the glass fiber bundle microstructure, degree of crystallinity and crystalline phases developed due to the flow were characterized using microscopy and X-ray diffraction methods. The changes in the crystalline phases of PA6 were attributed to flow phenomena. These morphological changes within the material contributed to the significant change in the tensile strength and modulus in the flow direction. The average tensile modulus gradually increased from 9.6GPa to 14.9GPa for the specimens produced by full mold coverage and 50% coverage mold, respectively, followed by a decrease to 13.9GPa for the 40% mold coverage. The average tensile strength shows an increasing trend from 162MPa to 254MPa for the full and 60% mold coverage, followed by a moderate decrease to 210 MPa for 50% mold coverage and a sharp drop to 70MPa for 40% mold coverage. The previously developed finite element computational model was used to simulate tensile property distributions of tested organosheets, and progressive damage mechanisms were used to understand the effect of morphological changes on the mechanical behavior and failure mechanisms of organosheet.
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Publication Date: 2023/04/17
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