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倒梁壳单元


获得加筋板结构的位移场对于飞机或航空航天器等的在线监测非常重要。本研究提出了新的倒梁-壳单元，通过壳部分和肋部分同时测量的应变对加劲板进行全场位移重建。加劲板中的壳和肋部分由分别由 Mindlin 板理论和 Timoshenko 梁理论构建的逆壳和梁单元建模。为避免剪切锁定，引入了一个具有虚拟中间节点的新逆梁单元。给出了倒壳和梁单元之间的约束，以保证变形的一致性，并提出了两种典型的倒梁壳单元。引入了一种子区域划分方案，该方案使所提出的逆元能够重建由多个加筋板组成的 3D 结构的位移场。给出了悬臂加筋板和双边夹紧 3D 加筋板两个数值示例，以验证新提出的倒梁壳单元和子区域划分方案的有效性。还提出了一种应变片布置的元素选择方案，以减少使用的测量数据。结果表明，新的倒梁壳单元可以准确地重建位移场，并且引入的子面积划分方案保证了三维面板重建位移场的准确性，即使在使用相对较少的应变片时也是如此。