Damage evolution and repair analysis of PRSEUS curved panel under pressurization-compression loading

There are few studies on the pressurization-compression mechanical behavior of the pultruded rod stitched efficient unit structure (PRSEUS) in blended wing body (BWB) aircraft. Thus, finite-element models of PRSEUS curved panels with varying curvatures, prefabricated cracks, and repair strategies were developed in this study to fill this gap. The damage mechanisms under pressurization–compression cases were systematically analyzed through an improved Hashin failure criterion coupled with a damage-evolution scheme. The results demonstrate that curvature changes significantly affected panel stiffness and ultimate load capacity. Specifically, under biaxial compression, the frame-direction load capacity decreased by 23%–27% compared to uniaxial compression; prefabricated cracks reduced ultimate loads by up to 65% and 62% in the frame direction and the stringer direction, respectively; composite repairs effectively restored structural performance, and titanium-alloy repairs elevated frame-direction ultimate loads by 8.3%–15.2% over unrepaired panels. These findings support the design and damage-repair strategies for PRSEUS structures.