To obtain the displacement field of stiffened panel structures is very important for the online monitoring of aircraft or aerospace vehicles, etc. New inverse beam-shell elements are proposed in this study for the full-field displacement reconstruction of stiffened panels via strain measured by shell parts and rib parts simultaneously. The shell and rib parts in the stiffened panel are modeled by inverse shell and beam elements respectively constructed by Mindlin's plate theory and Timoshenko beam theory. To avoid the shear locking, a new inverse beam element with a virtual middle node is introduced. Constraints between the inverse shell and beam elements are given to guarantee the consistency of deformation and two typical inverse beam-shell elements are proposed. A sub-area division scheme is introduced which enables the proposed inverse elements for reconstructing the displacement field of 3D structures composed of multiple stiffened panels. Two numerical examples including a cantilever stiffened panel and a two-edge clamped 3D stiffened panel are given to demonstrate the effectiveness of the newly proposed inverse beam-shell element and the sub-area division scheme. An element-selection scheme for the arrangement of strain gauges is also proposed to reduce the measurement data used. Results show the new inverse beam-shell elements can reconstruct displacement fields accurately and the sub-area division scheme introduced guarantees the accuracy of the reconstructed displacement fields of 3D panels even when a relatively small number of strain gauges are used.

中文翻译：

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用于加劲板结构全场位移重建的逆梁壳单元


获取加筋板结构的位移场对于飞机或航天飞行器等的在线监测非常重要。本文提出了一种新的逆梁壳单元，通过壳测应变对加筋板结构进行全场位移重建零件和肋骨零件同时进行。加筋板中的壳和肋部分分别采用Mindlin板理论和Timoshenko梁理论构建的逆壳和梁单元进行建模。为了避免剪切锁定，引入了带有虚拟中间节点的新反梁单元。为了保证变形的一致性，给出了逆壳单元和梁单元之间的约束，并提出了两种典型的逆梁壳单元。引入了子区域划分方案，该方案使得所提出的逆单元能够重建由多个加筋板组成的 3D 结构的位移场。给出了两个数值算例，包括悬臂加筋板和两侧夹紧的3D加筋板，证明了新提出的逆梁壳单元和分区方案的有效性。还提出了应变片布置的元件选择方案以减少所使用的测量数据。结果表明，新的逆梁壳单元可以准确地重建位移场，并且即使在使用相对少量的应变片时，引入的分区划分方案也保证了3D面板重建位移场的准确性。