Restricted accessResearch articleFirst published online 2026
Experimental and dual statistical validation of additively manufactured thermoset CFRP composites: Using a Weibull–SPC framework for reliability assessment
Additive manufacturing (AM) of thermoset continuous carbon fiber-reinforced polymer (CFRP) composites offers significant potential for aerospace and defense applications; however, their statistical reliability characteristics remain insufficiently explored. In this study, ten unidirectional laminates were fabricated using an in-house-developed automatic fiber placement-based additive manufacturing (AFP-AM) system under controlled processing parameters. Rheological analysis was conducted to optimize tow-infusion temperature, while scanning electron microscopy confirmed strong fiber–matrix interfacial bonding. Non-destructive ultrasonic C-scan inspection revealed minimal defects, with void content consistently below 1%. Tensile testing of 40 specimens yielded an average strength of 1985.8 MPa. A dual statistical validation framework integrating Weibull analysis and statistical process control (SPC) was developed to assess reliability and repeatability. Weibull analysis produced a characteristic strength of 2022 MPa and an R2 = 0.93, indicating low strength scatter and strong statistical adequacy. SPC charts and Cp/Cpk indices confirmed that subgroup averages remained within control limits, demonstrating process stability. Strength variability was primarily attributed to tow-width fluctuations during processing, which led to overlaps, gaps, and localized matrix-rich regions that served as stress-concentration sites. The proposed dual statistical framework provides a robust methodology for quantifying reliability, repeatability, and process capability in additively manufactured thermoset CFRP composites for high-performance structural applications.
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