Fatigue performance of injection‐molded short e‐glass fiber reinforced polyamide‐6,6. II. Effects of melt temperature and hold pressure

Abstract

Tensile and fatigue properties of an injection molded short E-glass fiber reinforced polyamide-6,6 have been studied as a function of two key injection molding parameters, namely melt temperature and hold pressure. It was observed that tensile and fatigue strengths of specimens normal to the flow direction were lower than that in the flow direction, indicating inherent anisotropy caused by injection molding. Tensile and fatigue strengths of specimens with weld line were significantly lower than that without weld lines. For specimens in the flow direction, normal to the flow direction and with weld line, tensile strength and fatigue strength increased with increasing melt temperature as well as increasing hold pressure. The effect of specimen orientation on the tensile and fatigue strengths is explained in terms of the difference in fiber orientation and skin-core morphology of the specimens. POLYM. COMPOS., 32:268-276, 2011. ª

Frontal weld lines in injection‐molded short fiber‐reinforced PBT: Extensive microstructure characterization for mechanical performance evaluation

“…In addition, the flow during packing would also deform the WL plane leading to a smoothing of the FO gradient at core. The previous results agree with the findings in Reference , where the authors explain that during the postfilling stage, the viscosity in the core region is lower than the one in the shell layers leading to a higher orientation in flow direction.…”

“…A study suggests that during the packing phase, the FO at the core tends to orient more in the transverse direction . Using SEM images, an increase of thickness of the core layer has been noticed with higher packing pressure . On the other hand, using a theoretical model for long glass fibers, Tseng et al found that the core thickness is reduced and the fibers become more oriented in flow direction during the packing phase.…”

A Three-Phase Model Characterizing the Low-Velocity Impact Response of SMA-Reinforced Composites under a Vibrating Boundary Condition

“…Other factors that affect the mechanical properties, such as the fiber location, length, diameter, and orientation, have been studied by Thomason [5,6,7]. The effect of the mould flow direction (MFD) on the interfacial shear strength and the tensile strength of composites has been investigated [8,9]. The results indicate that the tensile strength (and elastic modulus) of samples machined perpendicular to the MFD are nearly 40% lower than that of samples machined parallel to the MFD.…”

Coupled effect of loading frequency and amplitude on the fatigue behavior of advanced sheet molding compound (A-SMC)

“…To study the cyclic loading frequency (f) effect, Handa et al 12 performed a study of fatigue behavior on glass fiber-reinforced polyamide at different frequencies ranging from 5 to 50 Hz and showed that increasing the frequency decreases the fatigue life and strength. Different authors [13][14] studied the effect of frequency during the fatigue test of nylon 66 reinforced with 30% short glass fibers and concluded that, for the frequency higher than 2 Hz, the rate of crack initiation and growth increase, leading to the decrease of life time. The self-heating is related directly to the viscoelastic nature of matrix and to the dissipated energy during fatigue tests.…”

“…This aspect has been noticed notably for short fiber-reinforced thermoplastic composites. [13][14][15] For instance, for polyamide 66 reinforced with short glass fiber, several works have shown that for low frequencies, there was only an effect of the mechanical loading, whereas for high frequencies a coupling between mechanical and thermal effects were observed and evidenced. 15 SEM micrographs showed that the matrix remained ductile locally around fibers before debonding.…”