Manufacturing defects in composite structures have long been a limiting factor in performance-critical components. These defects, including porosity and voids, can significantly alter mechanical performance, potentially leading to premature failure under fatigue loads. Rapid fatigue characterization methods are desirable due to the multiplicity of process defects in composites. This work presents an accelerated testing procedure for fatigue life characterization in the presence of process defects using surface temperatures generated due to self-heating via ‘passive’ infrared thermography (IRT). Initial estimation of process-induced defects has been done using ultrasonic inspection followed by a detailed characterization via micro-computed tomography (m-CT). The growth of process defects with increasing load levels in a typical staircase loading has been observed for additively manufactured compression molded 20 wt%. C/ABS system manufactured by Oakridge National Laboratory (ORNL). Additionally, a coupled thermomechanical viscoelastic continuum damage mechanics (CDM) model for fatigue damage accumulation and remaining life prediction for short fiber reinforced thermoplastic composite (SFTC) with process defects has been developed using a three-dimensional repeating unit cell (3D-RUC) with periodic boundary conditions (PBCs) considering SFTC microstructure with varying spatial location/orientation, shape, and volume fractions of defects obtained using m-CT studies. A user material model (UMAT) for matrix constitutively under cyclic loading within the commercially available finite element package Abaqus will be developed based on experimentally obtained matrix damage degradation rates. This combined numerical-experimental approach is expected to be instrumental in predicting the onset and progression of fatigue damage within these composites, offering insights into their long-term structural integrity.