Joint nonlinearity in a stiffened aluminium wingbox panel and what it requires of a reduced basis

2026-09-09

AI Summary

研究通过构建非线性有限元模型解决铝制翼盒面板的连接非线性问题，使用Newmark积分和基于投影的非线性降阶方法分析其影响。

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 $\pm20\%$ 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 $5.5\times10^{-4}$. 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.

Problem

• joint nonlinearity
• stiffened aluminium wingbox panel
• reduced basis
• modal response
• nonlinear model order reduction

Innovation

• joint nonlinearity
• model order reduction
• receptance