Viscoelastic-viscoplastic homogenization of short glass-fiber reinforced polyamide composites (PA66/GF) with progressive interphase and matrix damage: New developments and experimental validation

In this paper, an original probabilistic micromechanics damage framework involving multi-deformation mechanisms, based on the modified Mori-Tanaka and Transformation Field Analysis (MT-TFA) techniques, is developed to predict monotonic oligocyclic stress-strain responses in short fiber-reinforced polyamide composites. The proposed model allows simulating actual injection-induced fiber arrangement, which characterized by arbitrary fractions of randomly oriented fibers distributed laminate plane. Furthermore, MT-TFA approach employs a phenomenological consisting 4 Kelvin-Voigt branches viscoplastic branch, formulated under thermodynamics framework, describe rate-dependent viscoelastic-viscoplastic deformation ductile polymer matrix phase. addition, Weibull density function utilized simulate initiation coalescence void-type discrete vicinity fiber/matrix interphase, induced debonding as observed experimentally. parameters are calibrated against experimental response glass/polyamide (PA66/GF35) composites via uniaxial loading/unloading tests, taking into account orientation (ODF). reliability efficiency TFA schemes assessed vis-à-vis separate hold-out data subjected loading at various rates. Progressive interphase compared support technique's capabilities capture experimentally mechanisms. To accurately response, progressive degradation load transfer between phases introduced through reduction active length. latter considering effect void-damage content. new mean-field formulation provides accurate predictions overall complex paths. It can be combined with other techniques our future work, such cycle-jump, towards high-cycle fatigue short-fiber composite structures. • A proposed, method Analysis. first time that involves mechanisms integrates material microstructure for glass-fiber reinforced considers several simultaneously. Namely, described coupled damage. void creation accumulation. effective extensively validated