Multi-phase error-chain modeling with cross-phase covariance handoff for mean–dispersion optimization of thin-walled panel assembly

Large thin-walled aircraft panels exhibit phase-coupled deviation propagation across positioning, clamping, drilling–riveting, and release. Existing approaches are largely single-phase, limiting cross-phase uncertainty propagation and leaving reduction-induced interface bias unaudited. We develop a four-phase FE–MC–EKF framework in which a circular-buffer cascade implements cross-phase covariance handoff, and we control reduction-induced interface bias through a VPT frequency-band audit with ≥95% strain-energy retention. We further establish a path–energy–statistics mediation model that links feasible sequencing to modal-energy redistribution, enabling joint control of terminal mean deviation (μ) and terminal dispersion (σ) . In an industrial panel case, the global RMS deviation increases from 28.0±1.6 to 52.1±2.6 μm and relaxes to 46.8±2.4 μm ( μ =46.9 μm, σ =7.6 μm; r =0.43). Center-first sequencing reduces μ by 11.8%, while mirrored clamping tightens σ by 21.3%. Coupling a dual-response surrogate with reference-vector NSGA-III improves Pareto quality (HV=0.687, IGD=0.120) using 8,700 high-fidelity evaluations (≈18.9% fewer).