Bond strength uncertainty quantification via confidence intervals for nondestructive evaluation of bonded composites
In ultrasonic non-destructive evaluation of aerospace composite bond strength, large uncertainties and unreliable confidence intervals hinder safety-critical assessments. To address this under limited-sample conditions, we propose an optimized confidence interval construction method. Our approach integrates a nonlinear forward model with unknown-variance estimation to establish a novel stiffness-to-strength uncertainty propagation paradigm; incorporates coverage calibration to guarantee nominal coverage probability; and combines swept-frequency ultrasonic phase analysis with statistical inverse modeling for robust interval regression. In multi-noise simulation experiments, our method significantly improves confidence interval coverage—particularly under high-noise and parameter-boundary conditions—while simultaneously reducing interval width. The resulting intervals provide interpretable, verifiable, and quantitatively rigorous evidence for bond strength safety validation.