Joint nonlinearity in a stiffened aluminium wingbox panel and what it requires of a reduced basis
Abstract
A shell finite-element model of a stiffened aluminium wingbox panel, a laboratory structure shared by several experimental studies, is built with its plate-to-stiffener joints at the $78$ physical fastener positions and calibrated against measured modal data, a six-parameter sensitivity update of the substructure moduli within ±20% reproducing the first five measured modes to $1.1−−4.3\%$ with modal-assurance values of $0.88−−1.00$. Making the fasteners nonlinear, at equal mesh, mass and damping, shows that joint nonlinearity enters the response strongly asymmetrically. Hardening is almost invisible, at most +1% in frequency, whereas softening or slipping the joints moves the first three resonances by −2.1, −4.9 and −9.2%, and friction removes up to 80% of the resonant peak before it recovers. Newmark integration of all 18,804 degrees of freedom and a harmonic balance condensed exactly onto the joints and continued in arclength agree to 5.5×10−4. A projection-based nonlinear model order reduction then locates the criterion that a jointed structure imposes on a reduced basis. The binding quantity is not the linear response, which eleven vectors reproduce to better than 0.01%, but the receptance of the structure between the joints, of which $126$ global eigenvectors carry about 2%, and without which the reduced model overpredicts the hardening shift of the fundamental by a factor of thirty and returns a value beyond the rigid-joint limit of the panel.
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BibTeX
@misc{tantaroudas2026joint,
title = {{Joint nonlinearity in a stiffened aluminium wingbox panel and what it requires of a reduced basis}},
author = {Nikolaos D. Tantaroudas and Evangelos Papatheou},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.10088},
eprint = {2609.10088},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10088},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Joint nonlinearity in a stiffened aluminium wingbox panel and what it requires of a reduced basis
AU - Nikolaos D. Tantaroudas
AU - Evangelos Papatheou
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2609.10088
UR - https://arxiv.org/abs/2609.10088
AB - A shell finite-element model of a stiffened aluminium wingbox panel, a laboratory structure shared by several experimental studies, is built with its plate-to-stiffener joints at the $78$ physical fastener positions and calibrated against measured modal data, a six-parameter sensitivity update of the substructure moduli within ±20% reproducing the first five measured modes to $1.1−−4.3\%$ with modal-assurance values of $0.88−−1.00$. Making the fasteners nonlinear, at equal mesh, mass and damping, shows that joint nonlinearity enters the response strongly asymmetrically. Hardening is almost invisible, at most +1% in frequency, whereas softening or slipping the joints moves the first three resonances by −2.1, −4.9 and −9.2%, and friction removes up to 80% of the resonant peak before it recovers. Newmark integration of all 18,804 degrees of freedom and a harmonic balance condensed exactly onto the joints and continued in arclength agree to 5.5×10^−4. A projection-based nonlinear model order reduction then locates the criterion that a jointed structure imposes on a reduced basis. The binding quantity is not the linear response, which eleven vectors reproduce to better than 0.01%, but the receptance of the structure between the joints, of which $126$ global eigenvectors carry about 2%, and without which the reduced model overpredicts the hardening shift of the fundamental by a factor of thirty and returns a value beyond the rigid-joint limit of the panel.
ER -